The non return valve, where to fit them and why you might need one.
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- เผยแพร่เมื่อ 9 ก.ย. 2024
- This little plumbing beauty saves many headaches and worries. So where does it go and why would you need one? Al explains some of the many uses for this valve. If you know of any more let me know.
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Brilliant! They should be fitted everywhere! Cheers Al
great video, very easy to understand
i am agree with you.
Very useful, thanks, love the use of the drawings 👍
Thanks Philip.
thank you for this video, perfect explanation and great advice.
No problem.
Thanks once again for this very useful info its great you take the time to explain these things...............Cheers
Great information, my kitchen mixer does this, i am now going to fit one... cheers
Glad it was helpful!
Thanks Al.
Thanks for this video. Very helpful indeed. A plumber recently removed one to 'improve' the flow of hot water in his words. It has had the opposite effect and now I need to fix that. He hooked it out of the pipe that connected to our shower controller. Is there such a thing as just purchasing the but that sits inside the pipe?
No you have to get the complete thing.
Apart from the obvious whats the difference between a single and double check valve where would you use one instead of the other please ..Im fitying an outsude tap ..thanks goid videis
You will not need one for an outside tap, there are fitted into the tap already. A single check valve can be used for fluid cat 2. A double check for fluid cat 3.
2:15 - I don’t think it is possible for the hot line to fill with cold water and also deliver warm mixed water to the user.
If any amount of hot water is flowing for the user, then no cold water can possibly be entering the hot supply pipe pushing it backward.
If warm water is coming out the faucet then both supplies must be delivering some amount of forward flow and no backward flow.
Depends on the system used Combi or F and E.
@@dereton33 As I understand the diagram, the check valve is trying to prevent the sink mixer from forcing higher pressure cold water into a lower pressure hot line. No amount of malfunction in that mixer valve can allow that to happen if even a tiny bit of hot water makes its way out the faucet for the user.
Regardless of the heating system, the only possible way to get warm water at the tap is for some amount of the heated water to be flowing forward - which is impossible if any amount of cold water is entering the hot supply line at the mixer.
The user can cause the cold water to backflow into the hot line by shoving cork into the faucet and setting the mixer to warm, but if the water dripping past the cork is not 100% cold, they have failed to force one drop of cold water into the hot line.
Thanks sir!
No problem.
Hi lookig for advice getting new bathroom fitted i have 22mm system plumbers connected 15mm flexi and non return on hot tap on the bath the pressure is much lower on hot tap and kind off makes a noise when turning tap on .some plumbers have spoke to say never needed to fit non return
No need for them they do restrict the flow rate.
@dereton33 thanks I have no idea about plumbing what do you mean about flow rate restricted thanks Callum
Hey man, very helpful! I'm trying to make my own handheld shower head that's mounted bathside, I have hot an cold stops to regulate the temperature coming from each main line, then they join to one pipe for shower head fitting ....should I use a check valve for the this application too?
No not on a shower. It could reduce the shower pressure.
Hi. Great video explaining the uses of a non return valve! I have a question. I have a shower waste pump connected to the the shower tray and hot /cold pipes through a pressure sensor. The pump switches on when the shower is switched on, as it should. But, it sometimes switches on when the basin tap is opened. Would a non return valve help in this situation? Thanks buddy
Yes it should.
@@dereton33 you sir are a God send! I’ve just fitted one and it’s worked perfectly. Thank you very much!!
So I have a question. I live in a 7 bedroom house which was built 30 years ago to a very high spec. We don't have drinking water in our taps as this is the third world. I was tiny when it was built so most of the plumbing is hard for me to even understand. We have a pressure-pump installed and 3 separate gas geysers servicing 3 sides of the house for hot water. Recently, I added an electric geyser on top of one of the gas geysers. Do I need to add a no-return valve on the hot water line exiting the geyser? I've noticed that even with the pressure pump on, there's some time before hot water actually flows from the tap in the bathroom this geyser services.
I would certainly fit one.
❤you saved my day😂 I'll pay you with my thumb up and subscribe 😅
That`s all I will need ha ha thanks.
Would you or do you need one for filling your toilet cistern up?
No .
Hi do they help water pressure to prevent airlock?
Yes
Is it possible to put a non return valves before the incoming hot and cold feeds into a shower pump?
Yes so long as there is enough pressure.
@@dereton33 thank for the reply. Big time time saver and life saver!
Hi bud .. wondered if you can help bud.. My mixer tap keeps spurting hot water when turned on initially .. it has a non return valve on both hot and cold
Take off the non return valves. Or renew the taps.
I’ll give it try.. thanks Al . Much appreciated. Have a great Xmas
What about on a hydronic heating system with multiple zones - are they needed there? If so, should they be placed before or after the circulators, or doesn't it matter?
I would not use them on those systems.
Thank u sir
Is the return pressure can distroy the exchancer in combi boilers
No never enough pressure if there was the PRV would release.
Thank you for your excellent videos. Would this work for a shower, i have had a problem with the large hot water tank overflowing in loft. Changed ball valve adjusted float but it still overflowed. Have worked out somehow shower is causing it even when turned off if the mixer is left on a certain position! Assume cold (mains fed in Whole House) is going back up hot and filling tank through the outflow pipe?
Yes it should work fine Lizzie.
Thank you, keep safe and hope you're recovering well. Kind regards Lizzie
Solved my quandry, bought a new mixer tap for the kitchen and it came with a single non-return valve and I'm thinking which side, hot or cold? Now I know, thanks.
Excellent!
From what he said, hot water side.
I have a 1 pipe central heating system, and two of the radiators won't warm up, I've bled them an can get no more out of them, would it be worth me putting a non return valve on the flow of the radiators?
No, they need a lot of pressure to open. Try balancing the system, if that fails then remove the rads from the wall take them out side and flush them out.
Good video, thanks. Can you advise me before I 'LOSE IT?'
Moved my Auto mixer tape from my Appartment to my house, never had a problem until I did that, water started to exit the over flow, advised by a plumber to fix these, just done so now only hot water coming out & that is at a reduced rate! The arrows are facing the take on both pipes.
Seems like I can't win, this is winding me up so much,.
Thanks
Hot water may be to low a pressure to close valve.
@@dereton33Thanks, So why won't the cold come out?
@@dereton33 Could it be my crap boiler? I've had someone around as I've not long been here to look at instilling an En-suite, he said I'd need a new boiler for the pressure.
I'm struggling to get a constant heat on a bath tap shower mixer. Would a non return valve fix it?
No.
I found one of these on a 15mm pipe to one of my upstairs radiators where I noticed the floor had been cut open to fit/replace it in the past... No other radiators have one... Any ideas why it might be there?
Stop reverse circulation.
Hi
I have a health faucet with a non return valve. Does this need any adjustment? The water pressure is very low.
No . They are fixed.
What's the small bolt on the valve body used for ?
Hi are you in leeds. I need to fix 1 on washing machine
No sorry.
Do you not need these on the cistern feed? Also can you get isolation valves with built in NRV?
You cant get isolation valves with NVR built in. Not needed on the cistern feed.
@@dereton33ok thx
Where would you put a single or a double check valve?
Mixer tap feed on the hot, Cistern feed, roof tank feed and outside tap if it is one of the old ones without the valve fitted.
Ahh, so if one failed on a bath mixer it could cause vibration on a combi system. Cheers.
Hi, Can you use a NRV to prevent reverse flow on vented system?
Vented systems do not usually have enough pressure for them to operate properly.
@@dereton33 But at 2:45 don't you seem to be showing a vented hot water cylinder feeding the mixer tap?
So many older one or two bedroom flats in UK use only night-time (cheaper Economy 7) electrically heated hot water tanks, which on the top floor (at least) are vented to a loft "header-tank" (I don't know how they do it on the lower floors). The bathrooms are usually set up with only a bath filled with low pressure hot and mains pressure cold water. However if you want a proper shower, you either have to try and install an expensive instant hot water electric shower (which in flats with concrete ceilings and floors is difficult to install the necessary dedicated thick mains electric cable) or use a mixer tap with shower hose attachment and mix the vented hot with the mains cold water. The danger here is if the hot tap is accidentally turned on while the cold tap is already full on (such as when filling the bath with cold water only for rinsing washed clothes say) a large proprotion of cold water will low back up the hot pipe to the hot water tank and potentially over-fill the header tank!! Hence a very weak NRV check valve (before the hot water tank) would be very helpful.
its called back siphonage lads
I have a question? I want to install a garden spigot,tap. But I want to install it before the main water enters the house. That would save me the hassle to drill through the wall etc.. Cut the pipe, install a T junction and a vertical pipe with a tap on it and a non return valve. Is this ok?
Yes that`s fine.
@@dereton33 Thanks.👍
Hi I have a question, Our townhouse complex of 50 units did this.. Water Meters had to be removed to protect the geysers.
The existing installation has one pressure Reducing Valve per two residential units.
This has to be changed to place a Pressure Reducing Valve in every individual feed to each unit, then place the Water Meters upstream of each Pressure Reducing Valve. Do we need to add the additional Pressure reducing Valves?
+Saloshni Reddy No you only need one
Just so I understand this, each unit will have just 1 pressure valve each..right?