Should annual boiler service include checking the expansion vessel?

[jogu]

if you look at my earlier post, it tells you what BG do during a service, nothing mentioned about expn vssl checks in their literature!

Your literature seems different to mine, not sure why - to quote from the T&C leaflet they sent me:

"annual service: means a visit we undertake in each Period of Agreement to check the elements included in your Agreement are safe and in good working order."

To me, my boiler isn't in good working order if it's not got a good pressure in the expansion tank. It seems opinions vary on this though 🙂 and I don't know how to resolve the differences between the advert you quoted and the T&Cs I have from them.

 

[lame plumber]

get a decent company to service your boiler, and by service I mean service and not check!

 

[dancinplumba]

unfortunately your boiler MIs dont say check expansion vessel at service time, but you could ask to have it done 🙂

 

[Billy Bob Bob]

i would not check or top up a ev on a service unless customer described low water symptoms or a dripping prv what i would do is run it up see how far that needle goes and if its hitting 2.5 bar flag up theres a problem and price in a repair so no in a standard gas safety check or service its not covered if you have a service contract with repairs thrown in its still not part of a service but would be a breakdown so parts and labour are covered

 

[Millsy 82]

i would not check or top up a ev on a service unless customer described low water symptoms or a dripping prv what i would do is run it up see how far that needle goes and if its hitting 2.5 bar flag up theres a problem and price in a repair so no in a standard gas safety check or service its not covered if you have a service contract with repairs thrown in its still not part of a service but would be a breakdown so parts and labour are covered

Exactly what I do its a fairly easy problem to spot.

 

[DaveTidy]

I used to work at BG and they have never included checking the expansion vessel charge at any point, the boiler is meant to be drained to carry this out as there should be equal pressures on both sides of the diaphragms and they don't drain the boiler unless there is a reason.

In the service they should take a note of the system pressure and what it expands to under temperature as this would indicate a problem if it expands too much because of a lack of pressure in the EV so you would expect that to happen.

If you haven't mentioned any problems and the pressure didn't go above an acceptable range then I wouldn't think any on would be checking back pressure in the EV on a service unless the manufacturers specify it and it's not in the BG service epc as I've just looked.

 

[jogu]

I used to work at BG and they have never included checking the expansion vessel charge at any point, the boiler is meant to be drained to carry this out as there should be equal pressures on both sides of the diaphragms and they don't drain the boiler unless there is a reason.

In the service they should take a note of the system pressure and what it expands to under temperature as this would indicate a problem if it expands too much because of a lack of pressure in the EV so you would expect that to happen.

If you haven't mentioned any problems and the pressure didn't go above an acceptable range then I wouldn't think any on would be checking back pressure in the EV on a service unless the manufacturers specify it and it's not in the BG service epc as I've just looked.

Hi Dave, many thanks, that all makes sense and seems like a good explanation, didn't know the boiler had to be drained down to check it.

I'm not convinced the engineers have been checking the system pressure under temperature, I'll remember to ask them about that next time. I guess it's also something I can check myself - at what point is the pressure too high? I guess if it's 1 bar cold, anything over 2ish when upto temperature would be bad?

 

[SimonG]

Boiler doesn't need draining as such, just de-pressurised.

 

[DaveTidy]

SimonG is correct. As long as either side of the EV diaphragm are equal pressure then it should give a true reading but you will find quite a few manufacturers used to ask for th boiler (nomally a combi) to be drained, as long as the pressures are equal.