Very informative. I encountered this very air lock yesterday. Drain the system down to change leaking radiator valve. Customer also complained that some radiators are not coming on at all. Before I change the leaking valve. I did a basic check on the radiators that are not coming on. I checked if Trv are stuck but they are fine. flow pipe to these radiators are very cold. Immediately I suspected sludge in the system. I confirmed this to customer by taking one small radiator off the wall. The system was badly sludged up, very blad tick water. I told him he needs a complete power flushing of the whole system. I proceeded in changing the leaking radiator valve. I had to drain the whole system and F&E valve off to do this. When i finished I fill system again by turning F&E stopcock on. I got massive airlock that even took more time than changing leaking valve. Some radiators eventually came on hot but down stair radiators are dead cold and boiler was on and off. Customer call me again when I left but I told him, he need power flushing. That system completely drained me out
Great videos mate bit of a good one here for you why have I got hot water backing up threw the expansion pipe and filling the tank on central heating side 👍
Air can be just as much of a problem in sealed systems. Even with inhibitor in the water, there is always a reaction between copper pipework and the hydrogen in the water, and hydrogen gas is released. I had this with more than one sealed system. On my present one I had a flow and return run into the loft, with an auto vent installed. This wastes some heat, but there is never any gas in the rads. Modern boilers almost always have an auto vent, but unless the boiler is at the highest point of the system, this vent will not prevent all “air”. Well, that’s been my experience....
Happened to me just this week. Air in system. Tried to bleed - no air coming out! Obviously got blockage in F/E feed ! Bugger! Rigged up a Rothenberger pump on to the expansion pipe thinking it would blow it through. Wrong! It pressurises the system a little and I can bleed a bit out but numerous trips up to the loft and back knackered me out! Feel a power flush coming on! TBH I really need to change the boiler (40+ years old) but it just keeps going!
What a great video. I recognise a lot of the problems here like air and sludge. I have/had an F&E system with an overflow tank in the loft. When I had some issues a while back which I think was cause by low pressure (possibly) the guys that came to check couldn't find the overflow tank in the loft cause it was at the other end of the loft to the main tank when I think it's more common for them to be closer together. The second guy, cause he couldn't find the overflow tank, turned the system into a pressurised system with a filling loop, etc. Only after setting this up did we find the overflow tank which is still there in the loft. Is this set-up/system likely to cause problems? The main issue I have is that all the rads are not getting hot. Upstairs rads and kitchen area seem fine but very little heat going into the lounge and dining room. The thermostat is in the dining room and since there is less heat in that area the boiler is having to work a lot harder than otherwise. The system was fine until a couple of winters ago when downstairs suddenly went cold. Since then the system has not worked well. I have an Intergas boiler which is about 7 years old and is located in the utility, next to the kitchen. Any help/advice would be welcome.
You F and E tank would have been cut out of service once the pressurised system was fitted. To sort out the rads not getting hot, try balancing the system.
Just wondering, my system has a combined feed and vent pipe, a single pipe running to the bottom of the expansion tank, as that’s underwater I’m assuming it couldn’t drag air into the system? - with this type of system what could possible be the culprit for air buildup? - can sludge build up itself be creating air through boiler Kettling?
I have mitsubishi ecodan and radiators. They set me curve with settings - max55C water at -12C and max 30C water at 30C. I have problem with temps, when is cold outside,below +3C to -5C everythink works fine. When temps are +7C outside, heatpump set water at 36 because of curve settings and after that it stop changing temps, no metter if temps outside drop to -1C. Its just stay at 36C.. i dont understand
Great video, I have the first drawing you showed, 3 way valve changed but I've noticed my vent pipe that you mentioned could suck air down is completely blocked at the T where it goes to the header tank, should I unblock this vent pipe or just leave it alone. First time in 20 years it's had any work done in this area so guessing it's been blocked along time. Many thanks and great videos.
Hello, l have followed your brilliant advice, as one of my radiators was cold at bottom. (Largest one downstairs) Removed the radiator flushed thru, (not to dirty) replaced it added inhibitor and bled it. On testing now ALL my rads are cold at the bottom. Pls help with any recommendations? Massive fan. Veronica
Hi Veronica, check the central heating pump is working ok if it has a speed setting turn it up to full speed. If you use a combi try turning the heating stat up 10 %.
a friend has a glowworm combi boiler and the water temp is fine, around 50c but the radiator temp goes up to 77c and 2.3bar (from 1.4 bar!) and cant change it on the boiler front. any advice?
@@dereton33 there are controls for tap water and rad water. tap water can be adjusted with + and - but the radiator one says "no" when you press anything. turning the room stat up or down does nothing, the radiators are scalding to the touch
I have just had my boiler serviced....before the service there were no problems. Since the service the boiler is kettling and the f&e tank water is getting very hot. Any ideas why a routine service should cause this?? And how to fix??
How would you know if the coil cylinder is blocked ? System has been cleaned using a magna cleasne Open vent and cold feed cut out and replaced Boiler is potterton 80 e F and e tank is pumping over out the open vent when hot water is on
i have the airlock problem - except the other way around in the hot water side and wondering if you could help me understand why - i recently installed a new shower (to replace the old bath) and with own pump, which has all been done correctly - however i continue to get airlocks each morning (yet i can not find any leaks occurring certainly not big enough to cause the size of airlock i experience each day. Not ethe system is around 40 years old and the traditional gravity fed system (rad I think on two pipe system) - possible the hot water and cold feed from header tank I think are the same pipe - Basically over night I get a build up air on the cold water feed side, and until I can clear this via the kitchen tap - no hot water will run - purely cold water out hot tap until the air is pushed out. Just for your knowledge there is also some form of cylinder problem that the hot water bleeds over into the radiator system (and presumable vice versa) yet even with this bleed over I am sure to if can cause the airlock problem I have - I rent and land lord isn’t doing much to resolve this issue and it driving me up the wall as it sort have me make a cup of coffee and breakfast (whilst running the hot water tape each morning) before there is any change of taking a shower in the morning. The only other thing I ve noticed is kitchen cold water runs fine a lot of pressure - which I thing is on it own split water supply from the main stop cock - yet when you hold the cold water pipe from the main stop cock that running vertically to the loft - it feel like its not a full bore of water (this when I am running the hot water tap to clear the air) feels like it maybe dragging air up the pipe - however once the hot water eventually get rid of the air and runs hot water, this pipe then feels like it more the full bore / full flow - so not sure if a faulty stop cock could be causing all of the above ? Again I don’t recall the airlock problem being an issue in the summer seems to be a big problem now th heating is now on for winter - so I am not sure this cross over of hot water / rads is somehow causing the issue - this sort in my head explains why in the morning once the air lock is clear all is fine and then by late evening and over night - each morning the airlock is back with vengeance. I was hoping you may have some ideas why the above is occurring - could be a leak pre main stop cock in the ground leaking and air getting in - hence why I can not find a leak occurring indoors any where PS the head rad does also trap air which I do constantly bleed out - note also the whole system as been drained down / clear water with the fluids you put in, etc so it not sludge causing an issue - under there sludge in the cylinder ? Please help as it driving me nuts!!!!
The pump could be emptying your roof tank faster than it can fill up. Go check the main ballcock in the tank is flowing properly and not blocked, also that the water is at the correct level. As everything was ok before you fitted the shower and pump, your problem has to be because of it.
Thank you - the problem was there prior to the shower - hot tap sort of spurted air when running (both to kitchen sink and bath) but as it was a bath that wasnt so much an issue at the time just took longer to fill the bath. My new shower pump isnt using water quicker than it drawing out so that not an issue and in fact the pump has improved things (eg hot water as well be flow pressure) - other than this airlock issue (i thinking i ve perhaps got a nasty bend on either or both the cold main feed coming from the mains and on the hot water drop to the kitchen, sort can air in the system on those two pipes. The airlock does seem to be cold water side around the hot water cyclinder area (i am not a plumber by the way so found your video extremely helpful - so i am very guessing at its cause)- i ve been told its a head of tank issue and raising the tank may cure the problem - however i am not too convinced i think the system is drawing air in from the overflow pipe - when i put my thumb overflow ( when i had the bath) it would stop the spurting (i guessing i that i have a combined overflow and water feed - eg one pipe instead of two separate ones - you mention a valve being place in the overflow - which i was aware you do as clearly the overflow is intended to be an overflow, so is this some sort of pressure valve would open if water pressure built up ?? as maybe this solution to try first as an easy fix, again ruling out the air drawing in if doesnt cure the problem PS the overflow pipe was very close to where the hotwater dropped down into bathroom - which i though maybe the problem at the time eg that this drop of pipe when live running hot water sucked air in - this drop as now been capped off and feed now a lot further away. sorry as obviously very difficult for you to visualise without seeing pictures - however by watching your video a value in the overflow pipe may be the solution ????
I have a Megaflo system which periodically cuts out & I have to press the reset on the boiler, could this be caused by a pressure drop? Also is there a remote reset option as the boiler is in the loft, ideally I could reset via the hive system, one day maybe...
When I try to top up my boiler the pressure doesn’t go up and water is gushing outside of the house, I think that’s the overflow pipe??? If anyone can give some advice that would be great :)
I've had a long and pricey day with plummer looking at my system. We established a shorting pump, causing the mains to trip so that's been replaced along with the 3 port valve (and controller). Of course he's gone now but I've noticed the boiler fires up, the pump and valve activate, and I can feel real heat in the pipes around the tank... but the rads stay cold. Then the boiler turns itself off after 5 mins or so. I'm at a loss... and I'm cold! Air trapped?
I have another suggestion. Extend the expansion pipe so that it dips below the surface of the water in the fill tank. Then no air can get in. (Oops! or out ) My central heating system has a huge amount of air in it. The problem is I can't find a pump or any radiators or any pipes or any water.
As I always tell my ladies, "there's no accounting for experience." Thank you for sharing all those years of plumbing experience. Peace be unto you.
Thanks 😀
Very informative. I encountered this very air lock yesterday. Drain the system down to change leaking radiator valve. Customer also complained that some radiators are not coming on at all. Before I change the leaking valve. I did a basic check on the radiators that are not coming on. I checked if Trv are stuck but they are fine. flow pipe to these radiators are very cold. Immediately I suspected sludge in the system. I confirmed this to customer by taking one small radiator off the wall. The system was badly sludged up, very blad tick water. I told him he needs a complete power flushing of the whole system. I proceeded in changing the leaking radiator valve. I had to drain the whole system and F&E valve off to do this. When i finished I fill system again by turning F&E stopcock on. I got massive airlock that even took more time than changing leaking valve. Some radiators eventually came on hot but down stair radiators are dead cold and boiler was on and off. Customer call me again when I left but I told him, he need power flushing. That system completely drained me out
That`s plumbing for you.
Great videos mate bit of a good one here for you why have I got hot water backing up threw the expansion pipe and filling the tank on central heating side 👍
Blocked cold feed system needs cleaning out. Black sludge is the problem.
If that works tomoz then Fridays a good day lol will post if it works OK 😀
Air can be just as much of a problem in sealed systems. Even with inhibitor in the water, there is always a reaction between copper pipework and the hydrogen in the water, and hydrogen gas is released. I had this with more than one sealed system. On my present one I had a flow and return run into the loft, with an auto vent installed. This wastes some heat, but there is never any gas in the rads. Modern boilers almost always have an auto vent, but unless the boiler is at the highest point of the system, this vent will not prevent all “air”. Well, that’s been my experience....
Thanks John for your very informative comment.
mate great video ive just solved three problems from your video i thank you sir awesome work
Thanks 😀
I've been to a few this winter with the ball valve stuck shut on f&e tank, low on system water
Yes that is another usual problem
Happened to me just this week. Air in system. Tried to bleed - no air coming out! Obviously got blockage in F/E feed ! Bugger! Rigged up a Rothenberger pump on to the expansion pipe thinking it would blow it through. Wrong! It pressurises the system a little and I can bleed a bit out but numerous trips up to the loft and back knackered me out! Feel a power flush coming on! TBH I really need to change the boiler (40+ years old) but it just keeps going!
Keep the boiler you have one of the good ones.
I have put a new hotwater tank in and header tank cold tank same system used on heating side that's all and yes may need a good flush out cheers
What a great video. I recognise a lot of the problems here like air and sludge. I have/had an F&E system with an overflow tank in the loft. When I had some issues a while back which I think was cause by low pressure (possibly) the guys that came to check couldn't find the overflow tank in the loft cause it was at the other end of the loft to the main tank when I think it's more common for them to be closer together. The second guy, cause he couldn't find the overflow tank, turned the system into a pressurised system with a filling loop, etc. Only after setting this up did we find the overflow tank which is still there in the loft. Is this set-up/system likely to cause problems?
The main issue I have is that all the rads are not getting hot. Upstairs rads and kitchen area seem fine but very little heat going into the lounge and dining room. The thermostat is in the dining room and since there is less heat in that area the boiler is having to work a lot harder than otherwise. The system was fine until a couple of winters ago when downstairs suddenly went cold. Since then the system has not worked well. I have an Intergas boiler which is about 7 years old and is located in the utility, next to the kitchen.
Any help/advice would be welcome.
You F and E tank would have been cut out of service once the pressurised system was fitted. To sort out the rads not getting hot, try balancing the system.
Could also leave the system feeding form the f&e tank with a check valve on then cut expansion pipe and fit a expansion vessel and prv
Thanks for your input.
Thank you so much for these videos, I’m learning so much. 😊😊👍👍😊😊
Thanks for watching Lily.
Just wondering, my system has a combined feed and vent pipe, a single pipe running to the bottom of the expansion tank, as that’s underwater I’m assuming it couldn’t drag air into the system? - with this type of system what could possible be the culprit for air buildup? - can sludge build up itself be creating air through boiler Kettling?
Yes it does, just the normal operation of the boiler working produces air.
I have mitsubishi ecodan and radiators. They set me curve with settings - max55C water at -12C and max 30C water at 30C. I have problem with temps, when is cold outside,below +3C to -5C everythink works fine. When temps are +7C outside, heatpump set water at 36 because of curve settings and after that it stop changing temps, no metter if temps outside drop to -1C. Its just stay at 36C.. i dont understand
Great video, I have the first drawing you showed, 3 way valve changed but I've noticed my vent pipe that you mentioned could suck air down is completely blocked at the T where it goes to the header tank, should I unblock this vent pipe or just leave it alone. First time in 20 years it's had any work done in this area so guessing it's been blocked along time. Many thanks and great videos.
Get it clear as soon as you can James.
@@dereton33 oh, is it not good to have it blocked? What could happen. Thanks for your reply to
thanks al for sharing this information with us enjoyed the video.
Thanks Ratch. All the best
Hello, l have followed your brilliant advice, as one of my radiators was cold at bottom. (Largest one downstairs) Removed the radiator flushed thru, (not to dirty) replaced it added inhibitor and bled it. On testing now ALL my rads are cold at the bottom. Pls help with any recommendations? Massive fan. Veronica
Hi Veronica, check the central heating pump is working ok if it has a speed setting turn it up to full speed. If you use a combi try turning the heating stat up 10 %.
a friend has a glowworm combi boiler and the water temp is fine, around 50c but the radiator temp goes up to 77c and 2.3bar (from 1.4 bar!) and cant change it on the boiler front. any advice?
There should be a separate control for the heating temperature If not just turn the room stat down..
@@dereton33 there are controls for tap water and rad water. tap water can be adjusted with + and - but the radiator one says "no" when you press anything. turning the room stat up or down does nothing, the radiators are scalding to the touch
Best have someone come and look over your boiler and controls as something is wrong.
I have just had my boiler serviced....before the service there were no problems. Since the service the boiler is kettling and the f&e tank water is getting very hot. Any ideas why a routine service should cause this?? And how to fix??
No you had best get back the guy who serviced it.
How would you know if the coil cylinder is blocked ?
System has been cleaned using a magna cleasne
Open vent and cold feed cut out and replaced
Boiler is potterton 80 e
F and e tank is pumping over out the open vent when hot water is on
System is still blocked you made need a power flush.
@@dereton33 cylinder return is on 15 mm pipe
Boiler keeps starting and stopping could this be a circulation issue as pump is operating fine
Sludge or air in the system.
@@dereton33 the boiler fires up and cuts out after 5/10 seconds and repeats the process over and over
The pump is operating fine
Derek. Where did u get your jumper Derek. Love it
it was a present so I dont no. Sorry Helen.
i have the airlock problem - except the other way around in the hot water side and wondering if you could help me understand why - i recently installed a new shower (to replace the old bath) and with own pump, which has all been done correctly - however i continue to get airlocks each morning (yet i can not find any leaks occurring certainly not big enough to cause the size of airlock i experience each day. Not ethe system is around 40 years old and the traditional gravity fed system (rad I think on two pipe system) - possible the hot water and cold feed from header tank I think are the same pipe - Basically over night I get a build up air on the cold water feed side, and until I can clear this via the kitchen tap - no hot water will run - purely cold water out hot tap until the air is pushed out.
Just for your knowledge there is also some form of cylinder problem that the hot water bleeds over into the radiator system (and presumable vice versa) yet even with this bleed over I am sure to if can cause the airlock problem I have - I rent and land lord isn’t doing much to resolve this issue and it driving me up the wall as it sort have me make a cup of coffee and breakfast (whilst running the hot water tape each morning) before there is any change of taking a shower in the morning. The only other thing I ve noticed is kitchen cold water runs fine a lot of pressure - which I thing is on it own split water supply from the main stop cock - yet when you hold the cold water pipe from the main stop cock that running vertically to the loft - it feel like its not a full bore of water (this when I am running the hot water tap to clear the air) feels like it maybe dragging air up the pipe - however once the hot water eventually get rid of the air and runs hot water, this pipe then feels like it more the full bore / full flow - so not sure if a faulty stop cock could be causing all of the above ?
Again I don’t recall the airlock problem being an issue in the summer seems to be a big problem now th heating is now on for winter - so I am not sure this cross over of hot water / rads is somehow causing the issue - this sort in my head explains why in the morning once the air lock is clear all is fine and then by late evening and over night - each morning the airlock is back with vengeance.
I was hoping you may have some ideas why the above is occurring - could be a leak pre main stop cock in the ground leaking and air getting in - hence why I can not find a leak occurring indoors any where PS the head rad does also trap air which I do constantly bleed out - note also the whole system as been drained down / clear water with the fluids you put in, etc so it not sludge causing an issue - under there sludge in the cylinder ? Please help as it driving me nuts!!!!
The pump could be emptying your roof tank faster than it can fill up. Go check the main ballcock in the tank is flowing properly and not blocked, also that the water is at the correct level. As everything was ok before you fitted the shower and pump, your problem has to be because of it.
Thank you - the problem was there prior to the shower - hot tap sort of spurted air when running (both to kitchen sink and bath) but as it was a bath that wasnt so much an issue at the time just took longer to fill the bath. My new shower pump isnt using water quicker than it drawing out so that not an issue and in fact the pump has improved things (eg hot water as well be flow pressure) - other than this airlock issue (i thinking i ve perhaps got a nasty bend on either or both the cold main feed coming from the mains and on the hot water drop to the kitchen, sort can air in the system on those two pipes. The airlock does seem to be cold water side around the hot water cyclinder area (i am not a plumber by the way so found your video extremely helpful - so i am very guessing at its cause)- i ve been told its a head of tank issue and raising the tank may cure the problem - however i am not too convinced i think the system is drawing air in from the overflow pipe - when i put my thumb overflow ( when i had the bath) it would stop the spurting (i guessing i that i have a combined overflow and water feed - eg one pipe instead of two separate ones - you mention a valve being place in the overflow - which i was aware you do as clearly the overflow is intended to be an overflow, so is this some sort of pressure valve would open if water pressure built up ?? as maybe this solution to try first as an easy fix, again ruling out the air drawing in if doesnt cure the problem PS the overflow pipe was very close to where the hotwater dropped down into bathroom - which i though maybe the problem at the time eg that this drop of pipe when live running hot water sucked air in - this drop as now been capped off and feed now a lot further away. sorry as obviously very difficult for you to visualise without seeing pictures - however by watching your video a value in the overflow pipe may be the solution ????
I have a Megaflo system which periodically cuts out & I have to press the reset on the boiler, could this be caused by a pressure drop?
Also is there a remote reset option as the boiler is in the loft, ideally I could reset via the hive system, one day maybe...
Could be a sign of air in the system or the start of sludge build up.
You wouldn't happen to be in the North London area would you please dereton33?
Real sorry no. Devon .
Devon is lucky to have you@@dereton33. 👍🏼 I learn a lot from your videos but scared to action any of them in case something goes wrong.
Al how often should I drain my system and refill
Is a cleaner worth putting in
I’ve run mine for 25 years without a change!!
Wow you have been lucky. Should be done every 5 years.
dereton33 if I put a cleaner in do I have to drain it completely to start with
Yes you will.
Is it normal for the radiators to gurgle when they first fire up.
Yes.
How would convert air separator to h section?
Use an air separator.
@ I don’t want to as they block. Why should I not use h section?
Rad in kitchen used to heat up but won’t anymore,gas heating system
Check for air first followed by the thermostatic rad valve is not jammed, then some system balancing.
When I try to top up my boiler the pressure doesn’t go up and water is gushing outside of the house, I think that’s the overflow pipe??? If anyone can give some advice that would be great :)
It is the PRV stuck open.
I've had a long and pricey day with plummer looking at my system.
We established a shorting pump, causing the mains to trip so that's been replaced along with the 3 port valve (and controller).
Of course he's gone now but I've noticed the boiler fires up, the pump and valve activate, and I can feel real heat in the pipes around the tank... but the rads stay cold. Then the boiler turns itself off after 5 mins or so.
I'm at a loss... and I'm cold!
Air trapped?
Air in the system, try bleeding the pump.
I have another suggestion. Extend the expansion pipe so that it dips below the surface of the water in the fill tank. Then no air can get in. (Oops! or out )
My central heating system has a huge amount of air in it. The problem is I can't find a pump or any radiators or any pipes or any water.
Now that is a problem.
have you fallen out with your boiler? you seemed inseperable lately, now it is just you and no boiler in sight!
We did have something going but it`s all over now.
@@dereton33 I bet it was hot action as well!