Top up expansion vessel

[micpwelsh]

Hi I've got a baxi 105e , it seems to be working great but I've just realised when the heating is on the pressure is going up by more than 1 bar (previously I only ever noticed it going up by half a bar ) . Does this sound like the expansion vessel needs topping up with air ?

 

[ollski]

Yes but it'll wait until the next service

 

[micpwelsh]

Just had it serviced a month ago . Hopefully it will survive until the spring . It doesn't go into the red on the pressure Gage

 

[muggles]

It wasn't serviced properly then - checking and topping up the expansion vessel is a standard part of a boiler service

 

[micpwelsh]

I'll give the guy a ring , he's always been good . But maybe not if he isn't checking things he should

 

[oilhead]

It wasn't serviced properly then - checking and topping up the expansion vessel is a standard part of a boiler service

Who is to say that it was not alright when serviced? An expansion vessel can fail in an instant; just like a light bulb.

 

[muggles]

Who is to say that it was not alright when serviced? An expansion vessel can fail in an instant; just like a light bulb.

A properly charged expansion vessel is under least stress and so it less likely to fail than once which is correctly maintained. Yes it could have failed in the month since the last service, but if it was recharged correctly at the service it's quite unlikely

 

[micpwelsh]

I'm going to call my gas guy on Monday , is it likely I will need a new expansion vessel ?

 

[muggles]

Possibly but it might just need the air side topping up. If the vessel does need replacing, the whole boiler usually needs to be removed from the wall to do the job. Alternatively an external vessel can be fitted elsewhere on the system, if a suitable location can be found

 

[micpwelsh]

Just out of intrest what would be an average price for an external expansion vessel to be fitted ? (In assuming this is the most cost effective and easiest option )

 

[muggles]

Around £100-150

 

[micpwelsh]

That's not bad at all . I'm guessing it must be a quick job for that price

 

[micpwelsh]

Just had a call with my gas engineer (he's coming tomorrow ) . He asked me to turn off the power to the boiler and press the tyre type valve at the top of the boiler and see if air or water comes out . Is this dangerous and what's the point of it ?

 

[Gasguru]

He wants to ascertain whether the vessel diaphragm has perished and allowing system water to pass across into the air side.
How large is the property? Installed in a larger house it's quite feasible for the pressure to rise a bar when up to temperature....the vessel is limited in size (to fit behind the boiler and with minimal cost) and generally copes fine with a typical small property installation.
Then again did he actually check the air pressure in the vessel at service time...most don't.
If the vessel has failed the flue would most probably have to be removed to access the vessel...it's sometimes necessary to plumb in an external vessel (to the boiler).

 

[micpwelsh]

The house is a 3 bedroom semi