thanks roger, great video, a word of caution for any DIY'er thinking of having a go at this, please go on the G3 course for unvented systems they are as cheap as £90 in places, because get things wrong and you can cause major damage to your house with these systems, the qualification gives you all the tools to fit this to building regs and to be safe!
Great Skill set with the Sweated Joints, love the slow pulled Swept Bend you're correct to plan and think out the Job always wondered why folks don't pull more 45 Degree set bends and further down another 45 Degree bend to allow smooth flow, many people go for those pre made up 90 Degree Elbows and fire a lot of them into circuits and then wonder why there a pressure loss ... great Upload...Job was a Credit to You...
Great video and tutorial. You sir are a legend sharing the right information and making it easy to follow no jargon straight to the point. Im a competent diyer and done some plumbing but using your guidance was able to replace an old vented tank system with an unvented one. Only thing i would add is that the tank i used was a different brand which had stainless steel pipe connections rather than threaded connection which recommended to solder. It turned out to be a right pain trying to solder copper to stainless steel due to lead solder etc. In the end i reverted back to brass compression fittings but had to ensure i really tightened the nuts to compress the olive properly with pfte around it as brass is softer than stainless steel. Had no leaks whatsover from the inlet and outlet since as i followed your video step by step. Thanks a bunch and keep up the great work you should be charging for this content 😂
Brilliant video, I'd of put check valves locally by hot taps/showers etc, as when you come to work on or replace appliances you'd have a field day with all that hot water not being drained from the pipework (soldering nightmare)...or stick a drain off after the check valve on the hot water supply off the cylinder so you can drain the pipework off any water. Just a thought. Cheers for all your videos again mate love watching this stuff! And don't think I'm having a go or anything as we're all here to give eachother pointers!
Thought about DIY-ing one of these some years ago as part of a solar hot water system I had an idea for. Didn't realise how complex it all was to manage the risks properly - so glad I never took it on! Roger you are a plumbing Jedi mate, 'Obi Wan KeBisby'!
Excellent and very informative video as usual. Many thanks. I’m asking as a layman, could this system be part of a multifuel system which comprises gas combi boiler supplying CH and HW alongside a multifuel stove I.e. wood and solid fuel, with wrap-around boiler?
Had a couple of Megaflows (only one had a valve/filter leak problem!). Currently we run oil - no gas - and our hot water is miles better than any of our neighbours. Several have resorted to a supply side pump. Unvented cyl's have only one drawback - initial cost and annual servicing - otherwise great. Thanks for the video(s).
Big fan, Roger. Looking at some back catalogue of yours. Two quick slightly related questions. 1. I increasingly work in public and quasihpublic sector projects where specs. almost ban 'hot works - what's your take on that? 2. I love my twin, in series, 300 litre pressurised solar tanks (big!). In winter, I rely on one of the immersion heaters on Economy 7. I worry about limescale in the tank and all its fittings. Do you think I could DIY descale the system, and how? Thanks.
Hi again Roger 👋 I have one of these in my property and that black opening that you can see into is dripping at about one drip every two seconds so from what you said it will likely need servicing. Can you recommend someone in the Witham area? Thanks Roger!
Hi Roger, I need your help please. Our regular boiler has just packed up. We're at a fix because we are planning to remodel the house to 6 bedrooms with 4 bathrooms and and upgrade to a solar compatible system boiler. This will also require upgrading mains pressure from the boundary. The whole house will be gutted and we'll move out. We need a boiler now as we are without heating and hot water. What do we do now? We're thinking of replacing it with in a cheap regular boiler for now. Your thoughts will be more than valuable. Thanks.
This pressure release pipe can be quite a big obstacle, I was looking to replace a vented system in a flat, the tank was in the middle under the stairs so no way to easily route downwards to the outside. In fact I think almost impossible.
What are the implications for the boiler of the motorised valve shutting off the hot supply to the cylinder? The boiler will presumably still be trying to pump into the cylinder...
Maybe it's different in England, but in Scotland the rules don't actually require the installer to have a specific certification, only that the installer be trained and experienced. Of course the best way to prove the training is certification by a recognized course, and for a person installing as a trade that is probably mandatory for insurance if nothing else, but it's not an absolute requirement for someone self trained who wants to install their own system.
Just had an Ideal 200L unvented indirectly heated stainless steel cylinder installed as a replacement for my 20+ year old unvented Tribune 150L steel cylinder with sacrificial anode. Cost was £1300. Works fine, apart from a slight trickle into the tundish when the boiler comes on after a period of inactivity for about 10 mins, which then slows to a drip and stops. He replaced the expansion vessel, T+P valve, and PRV, etc with new parts during the installation. The installer's been back to check the expansion vessel pressure, and other aspects, but can find no fault, so he doesn't seem very concerned. Is he right not to be botherered? What could be causing the temporary leak? The balanced cold water outlet is not being used from the combined PRV valve, so I've asked him if it could be the mixer valve in the kitchen or one of the two thermostatic shower mixers causing the leak, but he says no.
Great vid Roger and team. Can I ask a question, which is, why can't you use PEX pipe (Speedfit or Hep2o) as the pumped hot bypass? My kitchen sink tap is a long way from the current cylinder, and it takes an age, hence why I'd like to change to a pumped secondary return.
Wouldn't you have had a good chance of sussing out the heating coil configuration by removing the immersion heater temporarily and looking through its hole. Or just fit an air vent on the inlet connection, which is what I did.
I think the servicing of these units is a very easy job that most plumbers can do. It is just a question of checking the pressure relief valves and checking the pressure on the expansion vessel.
Very interesting, Roger. If you retro fit a house with this system is there a chance of old compression fittings and radiators leaking due to the increased pressure? Also, how do you flush flux out after soldering?
Hi Roger, Do these cylinders have a sacrificial anode in the top of them to protect the tank from corrosion? The ones here do have them but no one seems to remember to change it, or are aware of them most of the time. When they finally corrode out the tank lets go and starts to leak.
Well Roger a pressure control valve after the stopcock is a good start ! That way the whole system is regulated to 3 bar. As far as the secondary return is concerned you might find it will work on gravity with that building.hight.
Yes we tend to take the cold off after the pressure regulator to give balanced supplies. I like the gravity secondary return, I used to do that quite a lot. It siphons across bar mixers which used to be a problem on gravity systems
Hi David It is often done but it is not permitted. The only D2 pump I have seen that is rated for boiling water is around £750 I think somebody should make a cheaper one, they would clean up.
Roger, can I just be your apprentice please? When I've learnt everything you know, I promise I'll open a plumbing/ builders school - it'll be called "The Bisby Academy" - builders' equivalent of Oxford, producing brilliant all-rounders. That way Roger, your genius is preserved. Let me know what you think, please🥺.
@@SkillBuilder No to Aga… basically it’s a converted Barn only used on school holidays. Electric only supply, night storage heaters and a Vortic hot water cylinder heated by a immersion heater. The hot water pressure is a trickle because of no head ( cylinder at ground level ). Requirements are.. bathroom shower/basin and kitchen sink. It’s only occupied in the school hols so keeping a cylinder hot 24/7 365 is very cost effective. Any ideas what could be installed to give better pressure but does not need constant storage. Fischer stuff any good? Cheers Roger.
Hi skill builder, my partner has cold water running through the black unit you pointed at where you say 3 bar, and is at the 8.15 minute mark in the video, is this cold because the cylinder is pressured?? How do you stop the water from running constantly
Hi If the water is cold then it is coming from the mains going into the cylinder. There is a pressure relief valve red top in the top right of the picture as 8.15 mark and this relieves the excess pressure. Give the knob a couple of clockwise turns, it will open the valve and close it and this might allow it to seat properly. If that doesn't work it is best to replace that valve with another one. It should say 3 bar on the top. You are supposed to get a qualified person in to work on these units to avoid any mishaps but turning the knob around a few times is fine.
Great video with lots of information, just want myself to be clear; before upgrading these types of system should it be authorised through building control/Council? If that's the case, what sorts of form need to be filled in and who should it be sent to? Thank you.
Ha, Roger is not wrong about the state of the tanks we have in the loft. The ones in my place - a bit of insulation chucked on them (cold water and heating header) and are absolutely minging. That's why I am getting an unvented cylinder fitted - I get rid of those tanks. I wonder how many homeowners actually realise the state of those tanks - in my case the cold water tank feeds the upstairs taps......yuk.
4.56 have a look and tell me where you would connect it. There is a cylinder feed and a pressure balanced feed for the cold water. It just needs to tee into one of those. In my case I teed it behind the cylinder to make a neater job of it.
Trying to get my head around the technology here. If the tank is using mains pressure only, surely there is still going to be a considerable pressure drop when using 2 showers at the same time, no?
V T Yea there will be mate. old conventional systems work off a gravity feed from a tank in the loft, so the amount of ‘head’ you have from your roof tank will determine how much pressure you get from your tap. Combi boilers have flow restrictors built in them to reduce flow, so the boiler can still warm the water, because if the water flows to fast through them they can’t warm the water quick enough to the desired temperature The benefit with these cylinders, is that you have max 3 bar flowing into the cylinder, which is a fair amount of pressure (obviously if your incoming main is large enough to allow such a flow rate) But you will still get pressure loss when more than one outlet is drawn off, it’s just your hot water is drawing at a greater flow rate, so you will get better flow when more than one is used Hope that made sense for you
@@SkillBuilder let's hope you didn't dream it lol. Would be great to see it. I'm a Joiner and an old plumber mate will be coming in the new year to my 8 bedroom hotel and changing the old vented cylinder and ridding me of those dreaded storage tanks I've got over my now renovated rooms, can't wait to get a direct fed unvented in. I'm currently looking at the Kingspan you recommend, cost is as always an issue though. I'm hoping to watch information so that I can be more fluent in the process and help him to the best of my plumbing abilities.
hi roger i have a 5 bedroom house 2 bathroom 2 shower when ever i have 2 shower the hot water run out had to wait for 15 to 20 minute you think unvented cylinder will be the answer and do i have to change the boiler as well thanks enjoyed the video.
I think you might solve the problem by getting a better flow from the boiler to the cylinder. Is there a motorised valve on the cylinder? I am wondering if it is pumped or gravity.
Ratch Riat maybe you should look at the size of the cylinder capacity, compared to the size of the house There is a rule of thumb, but if you get a qualified professional to come and quote you, I’m sure they will be able to solve your problem 👍
Been looking to get one of these installed. At some point going to be getting solar and heat pump in near future so was looking to buy a heatpump and solar cylinder with the 2 internal coils. It won’t be hooked up to a high temp heat source such as a boiler. But as the heat pump and solar haven’t been installed yet, is it ok to blank off those coils and run it on the immersion heater that is built in?
The pressure relief doesn't blow off till 7 bar/ 8bar or 90degrees not just above 3 bar. If the cold mains can pressure the cylinder without a non return to those high pressures then the cold should be reduced with its own pressure reducer anyway. Don't want 7+ bar cold mains anyway.
Fantastic detailed video Roger thanks so much. One quick question is the pressure governor adjustable or is it factory set at 3 bar? Many thanks Chris 😊
Anyone know why unvented cylinders hold less water these days, i have a 210 litre slimline santon premier currently, but all the replacement 210 litre slimline units are too tall?
Hi Roger, can you explain why you cant take a balanced cold water feed from the output of the combination valve. i.e put in a tee on the output of the valve with one side being the feed into the cylinder and the other being the cold feed to the thermostatic mixer taps
You can but they give you a dedicated point which is more accurate because it balances them perfectly rather than letting the pressure favour the shorter pipe run.
Hey mate wouldn’t it have been better to have and isolating valve at inlet of cyclinder for servicing and have the limiting valve and cold water expansion at the bottom so that the cold water expansion would work before the tpr valve
Corban That is what I have. The cold water expansion vessel is on the cylinder side of the non return valve. You can see the isolating valve below the assembly.
Skill Builder yeah nah I meant cold water expansion right at the bottom of cyclinder as the tpr will go before the cold water expansion and a isolating valve straight off inlet of cyclinder great video just different seeing how other countries do there plumbing
The expansion vessel should be charged to 3 bar with the cold water inlet valve closed and the hot tap open. This means that when the pressure reducing valve limits the static pressure to 3 bar as the cylinder fills the expansion vessel will then accommodate the expanded water in the cylinder. If the pressure vessel is less than 3 bar it will already have begun to compress and that limits its capacity. In many countries they don't have an expansion vessel and the expansion backs up the mains. The non return valve, there to stop contamination, prevents the water backing up the mains so it needs somewhere else to go. Some cylinders have an air gap inside at the top to take the expanded water.
Nice job Roger , but you forgot to mention that you need to be qualified and certified to work on unvented hot water systems as if you don't know what your doing ( DIY ) you could be putting people's lives at risk.......! 👍
No you don't need to be certified, but you do need to be compotent. Don't let yourself be brainwashed. Wake up. I live in bulgaria and all the houses have these it's no big deal.
Why not have a pressure reducing valve on the mains coming into the building as well as the one in the combination valve? This would eliminate the need for a check valve on the hot water draw off.
17:36 Thank you for not putting a screw into the casing and the insulation of the cylinder. Almost everyone else does and they believe their pipes are “neat”
@@SkillBuilder cheers for your help!! Any recommendations on a pump to buy as ill probably go with the kingspan or megaflow for the cylinder so want to get a good one.
Oh dear, you have a different pressures for the hot water and cold water. Showers are going to be very hot/cold off and on. They should share the same pressure regulator. And I am only a DIYer not a professional, but it is rather obvious.
sorry I don't know what you mean, there is a take off for balanced pressures but in a house where all the cold services are in and the boiler is in the basement it is easier to put the cold on a separate pressure regulated supply. The showers are thermostatic so there is no problem on nominally equal pressures.
@@SkillBuilder Agreed, they'll probably be fine as is, most showers will accommodate an inbalance in pressure and if not, another pressure regulator on the cold will sort things.
Can you do a video on poor central heating pipework design and lack of 22mm flow are return. Issues with multiple drops and use of micro ball pipe. Got an absolute tool of a plumber whos screwed up my sisters central heating
@@SkillBuilder i do the wet fit hang rads n do the flow return on 3 bed terrace house, boiler is baxi 80 he type installed in kitchen back of the terrace. I do the "c" shape in 22mm plastic and "t" off in 15mm vvv close to rad, hence theres a max 22mm flow rate with no drops!!! Dont even need to balance and increase boilers life as no air locks or restrictions, hence boiler having to do less work. If theres a attic room i use 22mm. I never deal with micro ball pipes and use plastic as less restrictions. If theres a concrete floor down stairs i chase the skirting and take pipes around the skirting. I never use drops unless its a loft room. Even then i dont need to balance. I know im talking about small houses and basic system, but ive seen dumb plumbers screw these up aswell
@@SkillBuilder he left the site with a gas leak. People must get the gas safe engineer to watsapp their card and verify the certification. Ask the specifics of the pipe route and the 22mm path
Hello Kev The cylinders are not that expensive now. Say around £500.00 for this one. The pipe and fittings added another £200 and then there is my labour which is another £500.00 All plus vat of course.
I charge £1500 on average, supply a fit. Then its between £300 - £800 for any additional alterations to the system. Boiler would be about £1500-£2000 supply and fit.
The unvented cylinder was invented by an Englishman in the 1800s. Because of the explosive nature they were banned until 1986. Mains pressure DHW using low pressure thermal storage was catching on in the 1980s, however jobbing plumbers never understood them. Then unvented cylinders came in, so they bought them.
@@johnburns4017 OK. The DPRK invented both the vented and unvented cylinder in 1681. Looks like the patent ran out and Thomas Hawksley started to manufacture them. Which is OK to do as there is no patent infringement.
Here's the way to test which is the high side on the primary. Temporarily attach a fitting with an elbow to the end you think is the high one, and then pour in some water from a jug using a funnel. If it's the high end, it will pour out the other end before too long.
Forgive me if I'm being dense here but how can there be a high side if they're both at the same height? If they were not at the same height, wouldn't you just be able to look at it? And if they are at the same height why wouldn't this water level trick work basically the same regardless of which connection you use, give or take a little turbulence? In any case, page 3 of brochure on plumbase site shows cutaway drawing of ultrasteel cylinder with the coil running continuously from the connection left of immersion and then shooting up from the bottom to exit via the right connection. BUT the installation instructions, which describe the left connection as flow and right as return also seem to say it doesn't matter: "Either primary connection may be used as the primary flow. Reheat times are identical" which is just as well really because if the distinction was important you'd have thought they'd have made it impossible to mix them up.
Mentorcase , think 22mm punches through wall to out side. In oz, internal storage hotties must also have drip trays and outlet point, just in case hottie cracks or leaks.
ive got an unvented cylinder like this and every few months the overflow leaks. Never been able to work out why. Have put pressure reducing valve on mains into house at 2 bar but it still occasionally drips. I have to reset the airgap on the cylinder then its ok for 2-3 months. All valves have been replaced but it still does it. Don't know why. :(
Try fitting an expansion vessel to the incoming mains on the cylinder side of the non return valve. The bubble is being displaced, they are like that sometimes.
@@SkillBuilder Thanks so much for your reply. It is a megaflo. I've read they can do this. The last British Gas plumber mentioned that it might need an external expansion tank if the mains pressure reducer didn't fix it. But doesn't an external expansion tank simply increase the time taken for the valve to start to drip? Thank you 😀
suppose depends on size of ya house ! but i mean i lived in a 3/4 bedroom houses and heating and hot water supplies all been sufficient with a combi and electric showers is a better choice anyway IMO over hot storage tank feed
Matthew Trott a high temp pump costs £150 or so, you then run the pipe to your nearest waste pipe. They’re not that expensive and it depends where the waste pipe was to your basement
1. What procedures are involved in the annual service? 2. Is it possible to provide more than mains pressure? i.e. for occasions when two showers in use at the same time, plus the washing machine and dishwasher were cutting in while someone else is using the hose pipe to wash the car?
Twig You can fit devices to boost your cold main after it enters the property. Some can be pressure sensitive, so once it drops below a certain pressure, the pump will activate and bring the pressure back up for you If you contact your local qualified professional, I’m sure they can quote you for the works you require
Twig I think that what you need is more flow, not more pressure. There is a limit to what you can achieve because mains boosting pumps are designed to prevent you sucking the water out of a neighbour's supply. If you want a lot of simultaneous use it starts getting expensive. As for the annual service it involves checking the pressure on the expansion vessel (3 bar) cleaning the debris filter and testing the pressure and temperature relief valves plus the non return valve. It is a good idea to run these a little because spiders can build nests in the pipes and block them.
@@SkillBuilder What's the best way to improve flow? Is it just wider pipes? The incoming supply to my tank is 22mm. My tank requires an anode. I'm not sure if I should use PTFE tape or not; any thoughts on that?
Another great video Roger really informative as usual. I have a question. About 5 years ago we had an unvented system fitted by a plumber who reccomended it to us whilst our house was being renovated. We had the pipework renewed and a 25mm blue pipe installed. However, we are only getting 10 litres a minute and 2.5 bar standing pressure. So you can probably imagine when we open more than one outlet, our flow decreases, but just opening a single tap, the pressure and flow is good. Is there anything that can be done to improve our pressure and flow?? Many thanks
MH 1127 I have had much the same experience at my house. The water company laid a new run of 25mm from the main to their stopcock at the boundary and I continued it in to the house. They were supposed to put a new tapping in the main but they used the old 1/2 inch tapping because they wanted to get home. I have the required 1 bar at the stopcock and they say that is all they are required to do so, despite having an unvented cylinder I have no choice but to pump it with a mains pump. My flow rate is around 12 litres per minute but at the top of the house we have a shower that will dribble out if there are other showers or taps being used.
@@SkillBuilder would a check valve on the hot supply after a tap stop the issue you mentioned with mains cold over whelming the hot too a tap or showwe valve ? Cheers great vid btw
thanks roger, great video, a word of caution for any DIY'er thinking of having a go at this, please go on the G3 course for unvented systems they are as cheap as £90 in places, because get things wrong and you can cause major damage to your house with these systems, the qualification gives you all the tools to fit this to building regs and to be safe!
Good advice. Thanks
Man your one smart plumber and very neat, I have yet to see one plumber in Australia that meets your standards.
He’s as rough as fuck when the cameras not rolling!
Great Skill set with the Sweated Joints, love the slow pulled Swept Bend you're correct to plan and think out the Job always wondered why folks don't pull more 45 Degree set bends and further down another 45 Degree bend to allow smooth flow, many people go for those pre made up 90 Degree Elbows and fire a lot of them into circuits and then wonder why there a pressure loss ... great Upload...Job was a Credit to You...
This is not just a video but a plumbing course.
Your channel is brilliant - thank you for sharing all this interesting knowledge!
Thanks Audiorack, we appreciate your positive feedback.
I know Im kinda randomly asking but does anyone know of a good site to watch newly released tv shows online?
He is learning on the job
This video Sir an absolute gem!!!Many thanks for your time and knowledge that you share with us!!!!
I like the way you present the presentation very very nice and clear explanation
Thumbs up Mr Roger
Great video and tutorial.
You sir are a legend sharing the right information and making it easy to follow no jargon straight to the point. Im a competent diyer and done some plumbing but using your guidance was able to replace an old vented tank system with an unvented one.
Only thing i would add is that the tank i used was a different brand which had stainless steel pipe connections rather than threaded connection which recommended to solder. It turned out to be a right pain trying to solder copper to stainless steel due to lead solder etc. In the end i reverted back to brass compression fittings but had to ensure i really tightened the nuts to compress the olive properly with pfte around it as brass is softer than stainless steel. Had no leaks whatsover from the inlet and outlet since as i followed your video step by step. Thanks a bunch and keep up the great work you should be charging for this content 😂
We converted from conventional system in a town house (tank bottom floor) to unvented. Best thing we ever done, pressure on top floor is fantastic.
Brilliant video, I'd of put check valves locally by hot taps/showers etc, as when you come to work on or replace appliances you'd have a field day with all that hot water not being drained from the pipework (soldering nightmare)...or stick a drain off after the check valve on the hot water supply off the cylinder so you can drain the pipework off any water. Just a thought.
Cheers for all your videos again mate love watching this stuff! And don't think I'm having a go or anything as we're all here to give eachother pointers!
Great video Roger, id be intrested in seeing how you changed the systme over from low to high pressure. Tidy pipework btw.
@@racitup4114 I am also looking for the video regarding changing pipework over in loft? Thanks
me too. cant find the video
Thought about DIY-ing one of these some years ago as part of a solar hot water system I had an idea for. Didn't realise how complex it all was to manage the risks properly - so glad I never took it on! Roger you are a plumbing Jedi mate, 'Obi Wan KeBisby'!
do you have a link to show the pipework changes made in the loft for vented to unvented cylinders?
Excellent and very informative video as usual. Many thanks. I’m asking as a layman, could this system be part of a multifuel system which comprises gas combi boiler supplying CH and HW alongside a multifuel stove I.e. wood and solid fuel, with wrap-around boiler?
Thanks Rojer lots of things learned from this video.
as always roger your reviews are exceptional great stuff
Had a couple of Megaflows (only one had a valve/filter leak problem!). Currently we run oil - no gas - and our hot water is miles better than any of our neighbours. Several have resorted to a supply side pump.
Unvented cyl's have only one drawback - initial cost and annual servicing - otherwise great.
Thanks for the video(s).
Big fan, Roger. Looking at some back catalogue of yours. Two quick slightly related questions.
1. I increasingly work in public and quasihpublic sector projects where specs. almost ban 'hot works - what's your take on that?
2. I love my twin, in series, 300 litre pressurised solar tanks (big!). In winter, I rely on one of the immersion heaters on Economy 7. I worry about limescale in the tank and all its fittings. Do you think I could DIY descale the system, and how? Thanks.
Hi again Roger 👋 I have one of these in my property and that black opening that you can see into is dripping at about one drip every two seconds so from what you said it will likely need servicing.
Can you recommend someone in the Witham area? Thanks Roger!
Hi Roger, I need your help please. Our regular boiler has just packed up. We're at a fix because we are planning to remodel the house to 6 bedrooms with 4 bathrooms and and upgrade to a solar compatible system boiler. This will also require upgrading mains pressure from the boundary. The whole house will be gutted and we'll move out.
We need a boiler now as we are without heating and hot water. What do we do now? We're thinking of replacing it with in a cheap regular boiler for now. Your thoughts will be more than valuable. Thanks.
This pressure release pipe can be quite a big obstacle, I was looking to replace a vented system in a flat, the tank was in the middle under the stairs so no way to easily route downwards to the outside. In fact I think almost impossible.
Thanks for this. Just need the how to install a gas boiler video now and ill be ready to upgrade my system!
What are the implications for the boiler of the motorised valve shutting off the hot supply to the cylinder? The boiler will presumably still be trying to pump into the cylinder...
The motorised valve switches the boiler and pump on and off. It has a relay switch inside
Maybe it's different in England, but in Scotland the rules don't actually require the installer to have a specific certification, only that the installer be trained and experienced.
Of course the best way to prove the training is certification by a recognized course, and for a person installing as a trade that is probably mandatory for insurance if nothing else, but it's not an absolute requirement for someone self trained who wants to install their own system.
Just had an Ideal 200L unvented indirectly heated stainless steel cylinder installed as a replacement for my 20+ year old unvented Tribune 150L steel cylinder with sacrificial anode. Cost was £1300.
Works fine, apart from a slight trickle into the tundish when the boiler comes on after a period of inactivity for about 10 mins, which then slows to a drip and stops.
He replaced the expansion vessel, T+P valve, and PRV, etc with new parts during the installation. The installer's been back to check the expansion vessel pressure, and other aspects, but can find no fault, so he doesn't seem very concerned. Is he right not to be botherered? What could be causing the temporary leak? The balanced cold water outlet is not being used from the combined PRV valve, so I've asked him if it could be the mixer valve in the kitchen or one of the two thermostatic shower mixers causing the leak, but he says no.
Best plumbing modification we ever made. Don't delay - do it
Very helpful video explains things well.
Great video like all of them just the right amount of info no overload !
Great vid Roger and team. Can I ask a question, which is, why can't you use PEX pipe (Speedfit or Hep2o) as the pumped hot bypass? My kitchen sink tap is a long way from the current cylinder, and it takes an age, hence why I'd like to change to a pumped secondary return.
Wouldn't you have had a good chance of sussing out the heating coil configuration by removing the immersion heater temporarily and looking through its hole.
Or just fit an air vent on the inlet connection, which is what I did.
Great job Roj.
Who will be servicing this system. As I have spoken to few people and they are unaware or do not want to do it for some reason.
I think the servicing of these units is a very easy job that most plumbers can do. It is just a question of checking the pressure relief valves and checking the pressure on the expansion vessel.
Ive Just done a 300lt at home same think the coil not marked, odd really for a nice cylinder 🙄 works mint 👍
Very interesting, Roger. If you retro fit a house with this system is there a chance of old compression fittings and radiators leaking due to the increased pressure? Also, how do you flush flux out after soldering?
Yes there is a risk of that
Hi Roger, Do these cylinders have a sacrificial anode in the top of them to protect the tank from corrosion? The ones here do have them but no one seems to remember to change it, or are aware of them most of the time. When they finally corrode out the tank lets go and starts to leak.
Well Roger a pressure control valve after the stopcock is a good start ! That way the whole system is regulated to 3 bar. As far as the secondary return is concerned you might find it will work on gravity with that building.hight.
Yes we tend to take the cold off after the pressure regulator to give balanced supplies. I like the gravity secondary return, I used to do that quite a lot. It siphons across bar mixers which used to be a problem on gravity systems
Very good job" always enjoy the videos , a well earned cuppa there.
Thank you Johnny I am getting so much stick here that it is good to have some likes
Is it permitted to have a condensate pump on the D2 pipe where a fall to the exterior of the building is not possible?
Hi David
It is often done but it is not permitted. The only D2 pump I have seen that is rated for boiling water is around £750 I think somebody should make a cheaper one, they would clean up.
Great video. On which part of the pipework is the expansion vessel connected? Is the pipe running round the back of the cylinder there.
Runs around the back and into the tee at the top of the combination valve where the cold main comes in.
HAPPY NEW YEAR Skill Builder Team Starting the new year as you left the old year with yet another brilliant production
The AudiStud
Thank you for all your great comments and input through 2018. Keep on keeping on
superb stuff as always Roger!!!
Roger, can I just be your apprentice please? When I've learnt everything you know, I promise I'll open a plumbing/ builders school - it'll be called "The Bisby Academy" - builders' equivalent of Oxford, producing brilliant all-rounders. That way Roger, your genius is preserved. Let me know what you think, please🥺.
Roger…. In your opinion, which is the best Electric Combi on the market.
My friend at the London Electric Boiler Company told me that nobody has made a reliable one yet. Do you have gaa?
@@SkillBuilder No to Aga… basically it’s a converted Barn only used on school holidays. Electric only supply, night storage heaters and a Vortic hot water cylinder heated by a immersion heater. The hot water pressure is a trickle because of no head ( cylinder at ground level ). Requirements are.. bathroom shower/basin and kitchen sink. It’s only occupied in the school hols so keeping a cylinder hot 24/7 365 is very cost effective. Any ideas what could be installed to give better pressure but does not need constant storage. Fischer stuff any good? Cheers Roger.
Happy new year roger mate thanks for the video have a great year
Steven
Thank you and the same for 2019
Sorry I got confused, dose it need any any filling loop to top up the system?
Be up by the boiler, no 💪
Would you ever have two tundish's for both pressure reducing valves so you could identify what one is failing?
You could but if the cylinder is letting out how water you will see steam.
This is a very specialist plumbing job! No DIY enthusiast should attempt this installation!
Hi skill builder, my partner has cold water running through the black unit you pointed at where you say 3 bar, and is at the 8.15 minute mark in the video, is this cold because the cylinder is pressured?? How do you stop the water from running constantly
Hi
If the water is cold then it is coming from the mains going into the cylinder. There is a pressure relief valve red top in the top right of the picture as 8.15 mark and this relieves the excess pressure. Give the knob a couple of clockwise turns, it will open the valve and close it and this might allow it to seat properly. If that doesn't work it is best to replace that valve with another one. It should say 3 bar on the top. You are supposed to get a qualified person in to work on these units to avoid any mishaps but turning the knob around a few times is fine.
Great video with lots of information, just want myself to be clear; before upgrading these types of system should it be authorised through building control/Council? If that's the case, what sorts of form need to be filled in and who should it be sent to? Thank you.
It needs to be done through a registered installer. They can register it for you
@@SkillBuilder I am a registered installer but never done it before hence the question and some guidance.
Amazing Roger
Ha, Roger is not wrong about the state of the tanks we have in the loft. The ones in my place - a bit of insulation chucked on them (cold water and heating header) and are absolutely minging. That's why I am getting an unvented cylinder fitted - I get rid of those tanks.
I wonder how many homeowners actually realise the state of those tanks - in my case the cold water tank feeds the upstairs taps......yuk.
Could not see where you connected the expansion vessel normally goes on the pressure reducing block thanks Kevin
4.56 have a look and tell me where you would connect it. There is a cylinder feed and a pressure balanced feed for the cold water. It just needs to tee into one of those. In my case I teed it behind the cylinder to make a neater job of it.
Anywhere after the none return valve and entry to the cylinder is fine.
Very nice idea and neat workmanship.
Buuuuttt, where's the insulation on the pipes?
Is the tank insulated?
Yes the cylinder is insulated. The heat loss from the pipes is something that a lot of customers don't mind in an airing cupboard.
is a very helpfull , maybe more peoples will use modern systems
OK, this did not actually answer my query, but this is a fabulous video and I wanted to say as much :)
excellent very clearly demonstrated
Trying to get my head around the technology here. If the tank is using mains pressure only, surely there is still going to be a considerable pressure drop when using 2 showers at the same time, no?
V T Yea there will be mate. old conventional systems work off a gravity feed from a tank in the loft, so the amount of ‘head’ you have from your roof tank will determine how much pressure you get from your tap.
Combi boilers have flow restrictors built in them to reduce flow, so the boiler can still warm the water, because if the water flows to fast through them they can’t warm the water quick enough to the desired temperature
The benefit with these cylinders, is that you have max 3 bar flowing into the cylinder, which is a fair amount of pressure (obviously if your incoming main is large enough to allow such a flow rate)
But you will still get pressure loss when more than one outlet is drawn off, it’s just your hot water is drawing at a greater flow rate, so you will get better flow when more than one is used
Hope that made sense for you
Towards the end of the video you mention a video/series detailing removal of the tanks and unvented cylinder. There is no link? I can not find it....?
I will find out what happened to it. I remember recording it or I dreamt it
@@SkillBuilder let's hope you didn't dream it lol. Would be great to see it. I'm a Joiner and an old plumber mate will be coming in the new year to my 8 bedroom hotel and changing the old vented cylinder and ridding me of those dreaded storage tanks I've got over my now renovated rooms, can't wait to get a direct fed unvented in. I'm currently looking at the Kingspan you recommend, cost is as always an issue though.
I'm hoping to watch information so that I can be more fluent in the process and help him to the best of my plumbing abilities.
Hey Roger is the other video you mentioned here at all can't seem to find it 👍
great video - one of your best
hi roger i have a 5 bedroom house 2 bathroom 2 shower when ever i have 2 shower the hot water run out had to wait for 15 to 20 minute you think unvented cylinder will be the answer and do i have to change the boiler as well thanks enjoyed the video.
I think you might solve the problem by getting a better flow from the boiler to the cylinder. Is there a motorised valve on the cylinder? I am wondering if it is pumped or gravity.
Ratch Riat maybe you should look at the size of the cylinder capacity, compared to the size of the house
There is a rule of thumb, but if you get a qualified professional to come and quote you, I’m sure they will be able to solve your problem 👍
Wouldn’t you put manual or auto air vents on the flow and returns into the cylinder ?
Maybe if they are coming up from the floor
Roger legend
Been looking to get one of these installed.
At some point going to be getting solar and heat pump in near future so was looking to buy a heatpump and solar cylinder with the 2 internal coils.
It won’t be hooked up to a high temp heat source such as a boiler.
But as the heat pump and solar haven’t been installed yet, is it ok to blank off those coils and run it on the immersion heater that is built in?
You don't need to blank them off. If no water is going in the flow nothing can come out the return of the coil
The pressure relief doesn't blow off till 7 bar/ 8bar or 90degrees not just above 3 bar. If the cold mains can pressure the cylinder without a non return to those high pressures then the cold should be reduced with its own pressure reducer anyway. Don't want 7+ bar cold mains anyway.
Fantastic detailed video Roger thanks so much. One quick question is the pressure governor adjustable or is it factory set at 3 bar?
Many thanks Chris 😊
It is factory set and should never be tampered with
@@SkillBuilder Thank you so much, very helpful 😊
Anyone know why unvented cylinders hold less water these days, i have a 210 litre slimline santon premier currently, but all the replacement 210 litre slimline units are too tall?
Excuse my ignorance. What happens to the central heating header tank in the loft when you fit an unvented cylinder?
You can still use it because the heating is separate but most people have a sealed heating sytems these days which is much cleaner.
Hi Roger, can you explain why you cant take a balanced cold water feed from the output of the combination valve. i.e put in a tee on the output of the valve with one side being the feed into the cylinder and the other being the cold feed to the thermostatic mixer taps
You can but they give you a dedicated point which is more accurate because it balances them perfectly rather than letting the pressure favour the shorter pipe run.
@@SkillBuilder Thanks Roger, keep the good work up.
We’re we can get this in 300 letr
Hi Rodger, did you fit the non return valve on the main hot water out of the cylinder?
No we went for the pressure reducing valve
Is this for pipes on the top of the cylinder?
Hey mate wouldn’t it have been better to have and isolating valve at inlet of cyclinder for servicing and have the limiting valve and cold water expansion at the bottom so that the cold water expansion would work before the tpr valve
Corban
That is what I have. The cold water expansion vessel is on the cylinder side of the non return valve. You can see the isolating valve below the assembly.
Skill Builder yeah nah I meant cold water expansion right at the bottom of cyclinder as the tpr will go before the cold water expansion and a isolating valve straight off inlet of cyclinder great video just different seeing how other countries do there plumbing
how much air pressure does the expansion vessel have for the 3,5bar of watter pressure?
The expansion vessel should be charged to 3 bar with the cold water inlet valve closed and the hot tap open. This means that when the pressure reducing valve limits the static pressure to 3 bar as the cylinder fills the expansion vessel will then accommodate the expanded water in the cylinder. If the pressure vessel is less than 3 bar it will already have begun to compress and that limits its capacity.
In many countries they don't have an expansion vessel and the expansion backs up the mains. The non return valve, there to stop contamination, prevents the water backing up the mains so it needs somewhere else to go. Some cylinders have an air gap inside at the top to take the expanded water.
Nice job Roger , but you forgot to mention that you need to be qualified and certified to work on unvented hot water systems as if you don't know what your doing ( DIY ) you could be putting people's lives at risk.......!
👍
No you don't need to be certified, but you do need to be compotent. Don't let yourself be brainwashed. Wake up. I live in bulgaria and all the houses have these it's no big deal.
Forgot to say that you can also connect them to solar or a wood burning stove.
Trevor Jones This ain’t Bulgaria pal 👍🏻
Trevor. Never do that. The wood burner is a no, no. It is not controlled and can boil very easily. Then you are relying on the safety devices.
Trevor Jones, In Australia Plumbing is a protected trade. That’s why you can drink the tap water here,
Why not have a pressure reducing valve on the mains coming into the building as well as the one in the combination valve? This would eliminate the need for a check valve on the hot water draw off.
You could do that yes. I have done it when people have excessive night time pressure.
17:36
Thank you for not putting a screw into the casing and the insulation of the cylinder. Almost everyone else does and they believe their pipes are “neat”
Surely by installing a check valve on the hot out will cause resistance?
A little but it is mains pressure to there is lots of flow.
check valves should be installed at each application, shower mixer or TMV etc, not at the source
Can you fit any in inline water filters with an unvented system?
when you install drainoffs upside down , they nearly always dribble from the valve, and not all down the hose!
Im looking to get a un vented cylinder fitted in my cellar but I'm unsure if I can as I have no drain for the run off. Is it possible??
Yes it is fine. It is done a lot and you can buy a pump. Chances are it will never happen so the pump needs to be run every so often.
@@SkillBuilder cheers for your help!! Any recommendations on a pump to buy as ill probably go with the kingspan or megaflow for the cylinder so want to get a good one.
Oh dear, you have a different pressures for the hot water and cold water. Showers are going to be very hot/cold off and on. They should share the same pressure regulator. And I am only a DIYer not a professional, but it is rather obvious.
sorry I don't know what you mean, there is a take off for balanced pressures but in a house where all the cold services are in and the boiler is in the basement it is easier to put the cold on a separate pressure regulated supply. The showers are thermostatic so there is no problem on nominally equal pressures.
@@SkillBuilder Agreed, they'll probably be fine as is, most showers will accommodate an inbalance in pressure and if not, another pressure regulator on the cold will sort things.
Do they do one with a log burner stove feed in.
No. I am afraid that solid fuel is not controllable so it needs and open vent. You can buy a vented version.
Fab video you r very watchable all the best.
Brilliant video well explained.
Is that magnetic stainless steel??
The casing is mild steel then there is insulation then stainless
Can you do a video on poor central heating pipework design and lack of 22mm flow are return. Issues with multiple drops and use of micro ball pipe. Got an absolute tool of a plumber whos screwed up my sisters central heating
O.K I can go through the basics.
@@SkillBuilder i do the wet fit hang rads n do the flow return on 3 bed terrace house, boiler is baxi 80 he type installed in kitchen back of the terrace. I do the "c" shape in 22mm plastic and "t" off in 15mm vvv close to rad, hence theres a max 22mm flow rate with no drops!!! Dont even need to balance and increase boilers life as no air locks or restrictions, hence boiler having to do less work. If theres a attic room i use 22mm. I never deal with micro ball pipes and use plastic as less restrictions. If theres a concrete floor down stairs i chase the skirting and take pipes around the skirting. I never use drops unless its a loft room. Even then i dont need to balance. I know im talking about small houses and basic system, but ive seen dumb plumbers screw these up aswell
@@SkillBuilder he left the site with a gas leak. People must get the gas safe engineer to watsapp their card and verify the certification. Ask the specifics of the pipe route and the 22mm path
Just checked my cylinder and there are no pipes connected to the boiler flow / return.
HI Roger its Kev how much would something like that cost? thanks mate
Hello Kev
The cylinders are not that expensive now. Say around £500.00 for this one. The pipe and fittings added another £200 and then there is my labour which is another £500.00 All plus vat of course.
I charge £1500 on average, supply a fit. Then its between £300 - £800 for any additional alterations to the system. Boiler would be about £1500-£2000 supply and fit.
1st. The D.P.R.K invented the unvented cylinder ! Not to be confused with uninventing the vented cylinder. You know it makes sense ！！
The unvented cylinder was invented by an Englishman in the 1800s. Because of the explosive nature they were banned until 1986.
Mains pressure DHW using low pressure thermal storage was catching on in the 1980s, however jobbing plumbers never understood them. Then unvented cylinders came in, so they bought them.
@@johnburns4017 So they uninvented the vented cylinder in 1986?
@@stakkerhmnd
No. Thomas Hawksley invented it in 1861. They _reinvented_ the unvented cylinder in 1986.
@@johnburns4017 OK. The DPRK invented both the vented and unvented cylinder in 1681.
Looks like the patent ran out and Thomas Hawksley started to manufacture them. Which is OK to do as there is no patent infringement.
@@stakkerhmnd
No doubt the DPRK planted them as a Communist plot.
You are so insightful.
Here's the way to test which is the high side on the primary. Temporarily attach a fitting with an elbow to the end you think is the high one, and then pour in some water from a jug using a funnel. If it's the high end, it will pour out the other end before too long.
That is a great idea. I didn't think of that.
Forgive me if I'm being dense here but how can there be a high side if they're both at the same height? If they were not at the same height, wouldn't you just be able to look at it? And if they are at the same height why wouldn't this water level trick work basically the same regardless of which connection you use, give or take a little turbulence?
In any case, page 3 of brochure on plumbase site shows cutaway drawing of ultrasteel cylinder with the coil running continuously from the connection left of immersion and then shooting up from the bottom to exit via the right connection. BUT the installation instructions, which describe the left connection as flow and right as return also seem to say it doesn't matter: "Either primary connection may be used as the primary flow. Reheat times are identical" which is just as well really because if the distinction was important you'd have thought they'd have made it impossible to mix them up.
Great review. Your the best.
Great video
Roger, where can I find the video of redirecting the water from the loft you mentioned?
We are going to try and make it this week. It got a bit delayed
@@SkillBuilder has that been released? Cheers?
@@SkillBuilder did it ever see the light of day ?
Thanks!
Thank you Luke
I am wondering where the outlet from the tundish goes? to a bucket on the floor?
Mentorcase , think 22mm punches through wall to out side. In oz, internal storage hotties must also have drip trays and outlet point, just in case hottie cracks or leaks.
Through the wall. It is a basement but one wall faces a sunken garden area with drainage channel.
But I thought it was a basement, below ground level.
@@SkillBuilder as its a boiling water outlet please show how its terminated outside
@@TheDickPuller
Where does the pipe go? The answer is, through the wall and outside into a drain.
ive got an unvented cylinder like this and every few months the overflow leaks. Never been able to work out why. Have put pressure reducing valve on mains into house at 2 bar but it still occasionally drips. I have to reset the airgap on the cylinder then its ok for 2-3 months. All valves have been replaced but it still does it. Don't know why. :(
Try fitting an expansion vessel to the incoming mains on the cylinder side of the non return valve. The bubble is being displaced, they are like that sometimes.
@@SkillBuilder Thanks so much for your reply. It is a megaflo. I've read they can do this. The last British Gas plumber mentioned that it might need an external expansion tank if the mains pressure reducer didn't fix it. But doesn't an external expansion tank simply increase the time taken for the valve to start to drip? Thank you 😀
The hardest part imo is terminating the prv valve outdoors from a hot press in the center of the house can be a nightmare
What was the price of that cylinder?
300 400
That's only reason I went for a combi was the pressure relief valve as I would have put in a basement the cost to pump it becomes ridiculous.
suppose depends on size of ya house ! but i mean i lived in a 3/4 bedroom houses and heating and hot water supplies all been sufficient with a combi and electric showers is a better choice anyway IMO over hot storage tank feed
Matthew Trott a high temp pump costs £150 or so, you then run the pipe to your nearest waste pipe. They’re not that expensive and it depends where the waste pipe was to your basement
1. What procedures are involved in the annual service?
2. Is it possible to provide more than mains pressure? i.e. for occasions when two showers in use at the same time, plus the washing machine and dishwasher were cutting in while someone else is using the hose pipe to wash the car?
Twig You can fit devices to boost your cold main after it enters the property. Some can be pressure sensitive, so once it drops below a certain pressure, the pump will activate and bring the pressure back up for you
If you contact your local qualified professional, I’m sure they can quote you for the works you require
Twig
I think that what you need is more flow, not more pressure. There is a limit to what you can achieve because mains boosting pumps are designed to prevent you sucking the water out of a neighbour's supply. If you want a lot of simultaneous use it starts getting expensive.
As for the annual service it involves checking the pressure on the expansion vessel (3 bar) cleaning the debris filter and testing the pressure and temperature relief valves plus the non return valve. It is a good idea to run these a little because spiders can build nests in the pipes and block them.
@@SkillBuilder
What's the best way to improve flow? Is it just wider pipes?
The incoming supply to my tank is 22mm.
My tank requires an anode. I'm not sure if I should use PTFE tape or not; any thoughts on that?
Another great video Roger really informative as usual. I have a question. About 5 years ago we had an unvented system fitted by a plumber who reccomended it to us whilst our house was being renovated. We had the pipework renewed and a 25mm blue pipe installed. However, we are only getting 10 litres a minute and 2.5 bar standing pressure. So you can probably imagine when we open more than one outlet, our flow decreases, but just opening a single tap, the pressure and flow is good. Is there anything that can be done to improve our pressure and flow??
Many thanks
MH 1127
I have had much the same experience at my house. The water company laid a new run of 25mm from the main to their stopcock at the boundary and I continued it in to the house.
They were supposed to put a new tapping in the main but they used the old 1/2 inch tapping because they wanted to get home.
I have the required 1 bar at the stopcock and they say that is all they are required to do so, despite having an unvented cylinder I have no choice but to pump it with a mains pump. My flow rate is around 12 litres per minute but at the top of the house we have a shower that will dribble out if there are other showers or taps being used.
The water company are as good as they get as we were pretty much told the same thing. Many thanks for your help.
@@SkillBuilder would a check valve on the hot supply after a tap stop the issue you mentioned with mains cold over whelming the hot too a tap or showwe valve ? Cheers great vid btw