Air release valve leaking at UFH manifold - why?

[deepblue]

Does anyone know why does an air release valve fail (ie leak) on a UFH manifold? This results in pressure drop on the boiler - so no hot water.

It happened about 18 months ago - and was replaced - and now it has happened again.

Is it just bad luck? Faulty part? Not correctly installed?

Is this kind of set up out of date?

Any ideas/comments much appreciated.

Thanks, D.

 

[ShaunCorbs]

Is it an auto air vent if so there fault is dirt in the system binds the internals up and doesn't seal and lets water out

Switch it to a manual air vent if you can

 

[townfanjon]

Yep , they are a pain pal , especially in boilers. Systems have to have crystal clear water and no debris to have any chance .

 

[deepblue]

Thanks for your replies guys. How would a manual air release valve work? Does it mean I have to periodically (weekly/monthly?) release 'air' by turning some valve? How will the manual valve not get clogged by dirt in the same way the auto air release valve does?

We do have that things fitted which is supposed to capture all the dirt and which gets emptied each year by the BG engineer on his annual visit - but I guess that does not mean the water is clean enough to avoid the damage to the valve.

Thanks, D.

 

[ShaunCorbs]

If your having to air the system once a week there's a problem, tbh you should only air the system when you've drained down

And the manual air vent they don't block up due to the air outle being slightly bigger and less to go wrong

 

[deepblue]

Hi thanks for your reply. Sorry for not understanding - but I'm not sure what "air the system" or "drained down" means. Can you explain?

Thanks, D

 

[ShaunCorbs]

only time you should air a system is when you drain down for maintenance or changing a boiler etc (removing the water from the system)

if your having to air the system once a week theres a problem

hope this helps, if not just say

 

[deepblue]

Hi - thanks for your reply 🙂 sorry I don't understand. I have never "aired" my system weekly or any other time. The original problem is that an air release valve has a very small leak and my question was about that. Then someone suggested a "manual" air release and I asked what that meant: ie - would I have to *manually* release air - or what? Maybe if you could take it step by step for me that would help, as I am not a plumber! Thanks for your patience and for replying when I am not understanding it.

 

[ShaunCorbs]

Hi - thanks for your reply 🙂 sorry I don't understand. I have never "aired" my system weekly or any other time. The original problem is that an air release valve has a very small leak and my question was about that. Then someone suggested a "manual" air release and I asked what that meant: ie - would I have to *manually* release air - or what? Maybe if you could take it step by step for me that would help, as I am not a plumber! Thanks for your patience and for replying when I am not understanding it.

you would only need to air it when you drain the system down

 

[Stigster]

Hi - thanks for your reply 🙂 sorry I don't understand. I have never "aired" my system weekly or any other time. The original problem is that an air release valve has a very small leak and my question was about that. Then someone suggested a "manual" air release and I asked what that meant: ie - would I have to *manually* release air - or what? Maybe if you could take it step by step for me that would help, as I am not a plumber! Thanks for your patience and for replying when I am not understanding it.

The automatic air vents will be installed at the highest point on that part of the system (your underfloor heating in this instance) to allow air out of the system/pipes as you fill it and subsequently vent any more air trapped in the pipework that should make it's way to the high point and then be bled out to atmosphere automatically.

An automatic air vent is not a necessity but some kind of air vent must be fitted. In your case the good people of the forum are suggesting replacing the automatic vent with a manual one. Once the system is filled and all the air bled out manually via the vent, the vent is then closed. Provided all the air was removed during filling and the system is working correctly you should rarely if ever have to bleed it again.

If the system is ever drained down (all the water taken out of the pipework) for maintenance or alterations/repairs, a plumber would use this manual vent to expel all air whilst they fill back up.

The reason a manual air vent is often preferable is because it is a much simpler device than an automatic one. A manual valve is basically just a small tap with a relatively large outlet compared to an automatic valve. An automatic valve has a float and a type of needle valve which opens to let air out but not water. The float can get stuck in place with gunk or scale or small debris, or the needle valve can easily become blocked causing it to either leak water or not do its job bleeding air out (needle valves in this case are tiny little things, easily blocked).

This is rather long winded I realise but I hope it makes things a bit more understandable.

 

[deepblue]

Many thanks for that reply, much appreciated!

Can a manual air release valve be easily retrofitted to a system which has the automatic type of valve?

 

[Stigster]

Generally yes. Most brands of manifold I've seen have either a male or female tapping of a standard size that will allow installation of a manual vent in place of the automatic. It's not a big job by any means. Someone who knows what they are doing and provided they have the part in hand it'd a 1 hour labour job, it won't even likely take an hour but it's normal to charge the hour for a job like that otherwise plumber would be doing the job for a tenner's profit, if that.

Do you know the make/type of manifold you have? If we can identify it, it may be possible to find out what sized manual air vent would fit.

 

[deepblue]

Hi there - regarding the manifold and possibly fitting a manual air vent.

The manifold looks like this (see attached) - and the air release valve which had some water (a few drops) was at the top right.

The make on the pump is Grundfos.

The other thing as you can see on the photo is that the 7 flow regulators (if I have named correctly) are quite dirty - I do recall them being a while back.

Many thanks, D.

 

[Stigster]

Your manifold is made by Maincor. The automatic air vents are made by Emmeti. Manual & Automatic Air Vents - Emmeti

The air vents come in regular sizes (male thread) from 3/8" to 3/4" - yours is likely to be either 3/8ths or 1/2". The automatic air vent unscrews anti-clockwise to remove.

I cannot tell without one being removed and have read the Maincor documents but I can't see a size for the air vent listed. The good news is which ever size it is a manual vent can be found to fit that. The manual one will look something like this and uses a radiator bleed key to open and close. https://images-eu.ssl-images-amazon.com/images/I/51K9v2XGAqL._SY355_.jpg

 

[deepblue]

Thanks very much Stigster!! Great research.

So should I say to my plumber something like: "Can you fit a manual air release valve this time please, because it is less likely to get blocked and cause problems in the future"?

 

[Dilalio]

Or... "I'm sick of the aav leaking on the UFH manifold! Can you get a manual one and fit it please" 🙂

 

[Stigster]

Thanks very much Stigster!! Great research.

So should I say to my plumber something like: "Can you fit a manual air release valve this time please, because it is less likely to get blocked and cause problems in the future"?

That's it!