Worcester Bosch 230 needs expansion vessel ?

[greencoat]

Hi all,

got a problem where the pressure kept dropping on dial. Topping-up, the needle rose very quickly. Had a guy drain the expansion vessel and recharge it to 1bar, but a few days later, it's back down to almost zero. There are no drips from the release pipe outside.

I measured the vessel and it says 4 PSI. Do I need a new one? Is it easy for a DIY-er to do? Any advice appreciated as I can't get in touch with the guy over the holiday.

Cheers,

Pete

 

[kevplumb]

put an external one on the return no valves or owt though it has to have a clear path at ALL times

 

[Agile]

Very unfortunately and its embarassing, but few gas engineers actually know how to repressurise an EXV.

See the FAQ on this site and do it yourself. All you need is a foot pump!

Then set the pressure in the water to 1.5 Bar and put a bottle or condom over the PRV vent and see if any water is discharged over a 24 hour period.

Be aware your boiler is getting a bit long in the tooth!

Tony

 

[greencoat]

Thanks for prompt replies,

I don't know about the idea of an external tank, there seems to be decent access to it inside if it just needs replacing.

Forgive me, but I thought that if it's filled with water only a few days after being drained, it meant the diaphragm's gone inside? It seems a bit mad to just drain and recharge it again, or am I missing the point? Is it that it wouldn't matter if I change the tank because if the PRV is leaking, it'll just fill up the new one?

Thanks for advice,

Pete

 

[Agile]

The point that you are missing is that there is no guarantee that the engineer correctly repressurised the EXV.

There could be other faults which might become apparent when you follow my request!

Tony

 

[bengasman]

If it is not holding the charge, it could also be a faulty schrader valve, (same as car tyre) 5 minute job to replace.

 

[BingoBongo]

check faq

 

[Martin44]

Thank you for the above good advice.

I had the same problen with my parent's boiler.

I repressurised the expansion tank according to the FAQ, It took me a few goes for it to remain stable, as each time I let water in again it altered the pressure in the bar gauge.

I found the the gas engineer did not repressurise the expansion tank when we asked him to fix it.