boiler pressure dropping after new rad added

[diyplumber1980]

Fit a new rad on a sealed system. The boiler is a combi and has an external pressure vessel, the size of a football. After the new rad was fitted, the pressure keeps dropping to zero. Checked for leaks, none found, rads are watertight. However water is dripping out of the boilers overflow pipe outside. I cant figure out why. All i did was drain system, fit new rad, refilled and now have this problem. Could there be no pressure in the external vessel? Could this need repressurising? Or has the pressure relief valve in boiler gone? Even though i didnt touch the prv?

 

[Agile]

You probably disturbed dirt which got into the PRV.

You can check the air pressure charge for the EXV.

I hope you did not use the PRV for draining the system!

Tony

 

[diyplumber1980]

Thanks for reply Tony.

Silly question but how can i check to see the charge on the external vessel? And if this is not charged, would it cause water to come out the overflow pipe?

No i definately did not use prv to drain system! Used drain point on lowest rad! If it is the prv does this have to be changed and do u have to be gas safe to do it?

 

[Agile]

The EXV can usually be recharged but see FAQ for how.

We don't know your boiler model. Or if the EXV is failed.

The FAQ has a lot of information on this.

Tony

 

[diyplumber1980]

Also just to add the hot water also stops working, and you have to keep resetting the boiler to get it to fire up for hot water. This problem also started at the same time.

 

[diyplumber1980]

fthe boiler is called Ethose 54c, never seen one before