Expansion vessel

[HawkWhiteFinger]

Does it matter if a heating expansion vessel is fitted with charge pressure valve top way round or charge pressure valve bottom way round?

 

[SimonG]

No. I always fit it easiest way round. It's on the air side so should make no difference.

 

[kimbo]

It doesnt matter which way as long as it is accessable to check and re pressurise it.

 

[HawkWhiteFinger]

Splendid, cheers lads.

Previous plant rooms I've seen them any way round, but I did notice that on unvented cylinders they say it should be mounted a certain way - I can't do those cylinders, was just an observation.

This is for a heating circuit and the label on the vessel shows it a certain way, but the fitting guide makes no reference to orientation.

 

[SimonG]

On unvented I always fit horizontal or with outlet at bottom (schrader on top) depending on space.

 

[heliotrope]

Does not matter if valve is top or bottom of vessel. Just be sure that system pressure is zero when
checking vessel pressure. It would be best for system to be open ended when doing this.
Also not a good idea to depressurize via the safety valve (unless you are looking for grief).

 

[SimonG]

Does not matter if valve is top or bottom of vessel. Just be sure that system pressure is zero when
checking vessel pressure. It would be best for system to be open ended when doing this.
Also not a good idea to depressurize via the safety valve (unless you are looking for grief).

I always depressurise through safety valve (oil boilers) as part of the service is to check operation of it. Yes they can be a pain, but had one last month that when I went to depressurise it was blocked with crap and wouldn't function.

 

[anz]

The life of the diaphragm is increased if fitted with the water side down.

Most people just choose the easier side depending on the installation.

 

[Best]

I always heard air side side down, (on heating systems i should add) but seems the vessels work & last okay either way.
I think important to join to return pipe, on suction side of pump if possible. Also best to avoid hottest system water at vessel anyhow.
If vessel is connected at top with a pipe that isn't going anywhere else, I think better a tee fitted with an auto vent above, like when a vessel is fitted separate to a boiler.
As said, always system to zero pressure before checking vessel pressure. Never over pressure the water on initial fill as vessel can corrode later - believe it or not.
As SimonG said, PRVs need tested anyhow, so why not open them to drop pressure? Just carry new ones with you in case you can't stop them passing.

 

[HawkWhiteFinger]

Was just wondering, why do some sealed system kits come with a T shape fitting where the vessel, PRV and filling loop are all together and some kits have everything seperately (where each item is installed seperately along the return pipe).

 

[AWheating]

Was just wondering, why do some sealed system kits come with a T shape fitting where the vessel, PRV and filling loop are all together and some kits have everything seperately (where each item is installed seperately along the return pipe).

costs?

 

[SimonG]

different manufacturers

different situations / space restrictions

 

[kozak1968]

Was just wondering, why do some sealed system kits come with a T shape fitting where the vessel, PRV and filling loop are all together and some kits have everything seperately (where each item is installed seperately along the return pipe).

I try to fit them with the strader valve pointing down. Sometimes in the morning before any draw off of water the system can make a "farting" noise which can be quite loud and annoying. The noise is caused by the dry diagphram rubbing on the vessel. Turning the vessel with the strader valve downwards, lubricates the diagphram so stopping the noise...

 

[scorps]

I was made to alter one i fitted with the valve at the bottom by an united utilities water inspector,
he told the site manager the reason but he forgot what it was, but insisted i changed it

 

[Dannypipe]

I try to fit them with the strader valve pointing down. Sometimes in the morning before any draw off of water the system can make a "farting" noise which can be quite loud and annoying. The noise is caused by the dry diagphram rubbing on the vessel. Turning the vessel with the strader valve downwards, lubricates the diagphram so stopping the noise...

Very interesting. I know the noise well. Had it with cylinders I've fitted, and infact have it with the one in my house. Last time I solved it when the manufacturer sent me a new expansion vessel they were trialling and it sorted it (22mm comp' connection and not a 3/4 to comp connection).

Anyway, if putting them in with the shrader valve to the bottom sorts this out I will start doing so myself.

I have some across them with a bracket welded to the actuall expansion vessel, with key hole slots in it. The orientation of these slots has always been to have the shrader valve to the top. If that makes sense.