expansion vessel

[pauls]

went out to an alpha boiler leak the other day sorted that condensate pipe had corroded off the trap. anyway it had an extra expansion vessel fitted asked the custard about it and he said it was fitted when boiler was installed cant see, why fit the extra expansion vessel

 

[Blake]

was the vessel on the CH side or cold supply?

 

[pauls]

didnt look to be honest but im off back there sometime this week to fit spares and will have a look. its a system boiler so asuming heating side

 

[mfgs]

On a big system sometimes the internal expansion vessels arent adequately sized for the system so another is fitted. Also I have seen it where people fit one externally to the boiler if the one in the boiler is knackered and a pain to change although doing so is a bit naughty.

 

[desrob]

if fittted on incoming cold water,as per m i quite normal

 

[mikeygas]

Why's it a bit naughty to fit an external expansion vessel? Some MI's say it's perfectly acceptable to do i.e ideal response, baxi 105 for example, as sometimes to replace an EV the boiler has to come off the wall.

The Alpha could also have been bought as a heat only boiler, and converted into a sealed "system boiler" by fitting an external expansion vessel and associated pressure relief controls.

 

[hydrotherm]

Done a new install last year and fitted heatline column rads to the ground floor of this rather large house. The water content of these rads was much more than you would have thought, done the calcs and the ground floor needed its own expansion vessel which was sited next to the boiler.

 

[Alpha man]

went out to an alpha boiler leak the other day sorted that condensate pipe had corroded off the trap. anyway it had an extra expansion vessel fitted asked the custard about it and he said it was fitted when boiler was installed cant see, why fit the extra expansion vessel

What Alpha model is it and is it a Heating only boiler? Most Alpha expansion vessels are only 8 litre models so in a larger system house a additional external vessel may be needed.

 

[McGoo]

Worcester greenstar recommend the fitting of an external expansion vessel if there is insufficient clearances on the top or sides to change the integral one if it has failed. I have done this myself as the alternative is dropping the boiler off the wall etc.