central heating expansion vessel

[keithblackwood]

i have had my new boiler, worcester, for 4 years, and in this time have had to replace the expansion vessel twice in the past and again now.

Has anyone any idea why they only last a short time as i am having to change it more or less every winter. The vessel is 8ltr. on a WORCESTER 28i JUNIOR

 

[kevplumb]

change it and up the pressure in it a bit depends on your system volume it could be undersized or at its limit

 

[doitall]

That would do about 6 average radiators.

Probably undersized, although I doubt they are busted, but just need re-pressurising.

 

[keithblackwood]

7 radiators, have checked pressure and reding one bar

 

[doitall]

We mean the pre-charge pressure, with the system on zero pressure.

 

[keithblackwood]

sorry do not understand your reply

 

[doitall]

sorry do not understand your reply

The vessel has a pre-charge but is not related to the pressure gauge on the boiler.

 

[Agile]

Look in this site's FAQ for instructions on how to pressurise the AIR side !

Before we can usefully suggest whats wrong, you will have to explain exactly hoe they fail !

Tony

 

[keithblackwood]

when i turn on the heating after 5 minutes when the rads are hot the pressure goes over the top and the relief valve dumps the excess pressure therefore shutting down the system with low pressure.

i have checked the vessel pressure and set it to manufacturers 1/2 a bar

 

[kevplumb]

try upping it to say .75

i assume you checked the pre charge as outlined in the FAQ

other option is to fit an external vessel as well

 

[keithblackwood]

try upping it to say .75

i assume you checked the pre charge as outlined in the FAQ

other option is to fit an external vessel as well

i am going to use an external vessel this time, and i have tried various pressures from 1/2 bar to 1.5 bar
Thanks

 

[kevplumb]

fit a larger one than is on the boiler

 

[doitall]

Yes at least 12Ltr and pre-charge it at 1bar.

An 18-20 Ltr would be even better if you have somewhere to hide it (cupboard perhaps)

 

[Agile]

i am going to use an external vessel this time, and i have tried various pressures from 1/2 bar to 1.5 bar

Thanks

I really do not think that you have followed the advice in the FAQ for repressurising your EV.

Its no good saying you have when the results clearly imply that you have not !

Please give us one aspect of the FAQ procedure to indicate that you have followed it.

If you actually do it then it will solve your problem! You seem hell bent on buying and fitting another one just because you dont want to follow our advice to repair your problem.

Tony

 

[keithblackwood]

i am going to use an external vessel this time, and i have tried various pressures from 1/2 bar to 1.5 bar

Thanks

I really do not think that you have followed the advice in the FAQ for repressurising your EV.

Its no good saying you have when the results clearly imply that you have not !

Please give us one aspect of the FAQ procedure to indicate that you have followed it.

If you actually do it then it will solve your problem! You seem hell bent on buying and fitting another one just because you dont want to follow our advice to repair your problem.

Tony

have followed the proceedure given by worcester, ie dump the water pressure the charge the ev.

quite frankly do not like your attitude