Cost of replacing expansion vessel on HRM wallstar system

[flameport]

1. Pressure going slowly down to 0. Have to keep topping up.

Pressure of what - The air in the vessel?
or far more likely - the pressure of the heating system?

Topping up what - The air in the vessel?
or
The water in the heating system?

 

[colinfifi]

1. Pressure going slowly down to 0. Have to keep topping up.

Pressure of what - The air in the vessel?
or far more likely - the pressure of the heating system?

Topping up what - The air in the vessel?
or
The water in the heating system?

Connected to the expansion vessel is the gauge which i guess reads system pressure - and should run around 1 bar.

Slowly over a few weeks drops to 0.

Get it back up by adding water via fill pipe.

Thanks

 

[oilhead]

Air may have come out, but how much is left in? The only correct way to check is to remove the vessel, recharge it to the prescribed pressure and refit. If you are still losing pressure, then look at the rest of the system.
(Faulty prv, air vent, or rad valve, blocked feed from system to expansion vessel) It is for specialist knowledge that you should expect to pay for a job done properly.

 

[colinfifi]

Air may have come out, but how much is left in? The only correct way to check is to remove the vessel, recharge it to the prescribed pressure and refit. If you are still losing pressure, then look at the rest of the system.
(Faulty prv, air vent, or rad valve, blocked feed from system to expansion vessel) It is for specialist knowledge that you should expect to pay for a job done properly.

I agree and will do . however engineer doing yearly service , when asked said it was the expansion vessel - needs replacing and would cost about £170 pounds and didn't know costof vessel.
So was just getting figures for comparison.

thanks