Boiler pressure 3 bar.

[ssb1973]

Hi all,

I have a Vaillant thermocompact 628E, the pressure was around 0.6 bar (It should be around 1.0) so I filled it from the filling loop to around the number 1. Afterwards, I've noticed when the rads come on, the pressure on the boiler goes over the red line after the number 3, causing the water to come out of the overflow. The filling loop is fine, it is tightly closed.

In the past, I used the pressure relief valve to reduce the pressure, however, I found that I had to get the PRV replaced as a result (this happened on two previous occasions). So, I'm reluctant to manually reduce the pressure from the PRV. Are there any other ways to reduce the pressure without turning the PRV?

In hindsight, I should've just left it as it was with low pressure.

 

[Echo the husky]

Have you read this page in the Wiki?

 

[slippyr4]

Your expansion vessel has quite likely failed.

 

[Nozzle]

You can reduce pressure using any of the bleed screws on any of the radiators or near the pump or somewhere near the high point of your system. Take heed though, that the expansion vessel membrane may or may not have failed - causing a large increase in pressure going from cold to hot.

Nozzle

 

[ssb1973]

You can reduce pressure using any of the bleed screws on any of the radiators or near the pump or somewhere near the high point of your system. Take heed though, that the expansion vessel membrane may or may not have failed - causing a large increase in pressure going from cold to hot.

Nozzle

Thanks, I've bled some of the upstairs radiators, but air doesn't come out, just water, the pressure has dropped a little. Just a note that the pressure going to 3 isn't a instant jump, but rather a gradual thing. Is there any value in using a footpump to pump up the expansion vessel?

 

[ssb1973]

Have you read this page in the Wiki?

Thanks, that was a useful article.