Problem recharging pressure vessel on Worcester 28CDI

[resetsony]

Hi All,

Seen a few topics here about this but can't seem to find one for my particular issue.

I have a problem with the boiler in that it is losing pressure and there is a drip on the release pipe on the outside. I check the pressure vessell and there is no air in it. So I drain the system down using the drain cock and use a electrical pump with a digital pressure gauge to pump it up after pumping for a bit I drain the extra water out of the boiler until nothing comes out and keep pumping. I set the pump to stop at 1PSI but the pump goes for about 4 minutes and can't see the pressure gauge going up on it so I stopped since this pump can inflate a car tire in 3 minutes, when I press the valve on the boiler air comes out. I know the pressure gauge is working since when I put it on a car tire it works fine. I think the pressure vessel is fine since no water comes out. Any other ideas as to what could be wrong? Thanks

 

[andytw]

You mean 1PSI or 1 Bar ?

andytw

 

[45yearsagasman]

The pressure gauge does not measure the charge pressure in the exp vessel, but measures the water pressure in the system once you refill it. If you've refilled the system and the gauge shows zero then either the gauge is faulty or there is a blockage behind the gauge. This is quite common and easy to fix.

 

[resetsony]

You mean 1PSI or 1 Bar ?

andytw

Sorry means 1BAR

 

[resetsony]

The pressure gauge does not measure the charge pressure in the exp vessel, but measures the water pressure in the system once you refill it. If you've refilled the system and the gauge shows zero then either the gauge is faulty or there is a blockage behind the gauge. This is quite common and easy to fix.

Ok will measure again once it is full, but how would I know how much air to put in once it is drained down and I am pressurising it?

 

[45yearsagasman]

De pressurise the boiler and pump the vessel to approx 1bar using your pumps gauge to measure. Remove the pump and then refill the boiler with water using the fill loop key until the gauge reads approx 1bar. Do this when the system is cold.

 

[resetsony]

De pressurise the boiler and pump the vessel to approx 1bar using your pumps gauge to measure. Remove the pump and then refill the boiler with water using the fill loop key until the gauge reads approx 1bar. Do this when the system is cold.

Thanks Pete. That's exactly what I did. The pumps gauge keeps reading 0 when I pump it up. I am thinking of giving it another try before I call the boiler guy in to have a look.

 

[Agile]

If the pump never creates a presssure then its because the EXV is leaking!

Its like pumping up a tyre with a big puncture!

New EXV time! At least on many Worcester boilers you can do that from the front. Many need an RGI if the gas valve needs removing.

Tony

 

[resetsony]

If the pump never creates a presssure then its because the EXV is leaking!

Its like pumping up a tyre with a big puncture!

New EXV time! At least on many Worcester boilers you can do that from the front. Many need an RGI if the gas valve needs removing.

Tony

That's what I thought must be some leak but can't hear any air or water escaping so not sure. EXV is not that easy on these.

 

[MJN]

No need to replace the internal vessel; far easier to fit an external one instead. DIYable if you're competent with some simple plumbing.

Mathew