Ferroli UV cylinder passing

[FarmerJon79]

Hi, I have a Ferroli 200l unvented cylinder, the temperature/pressure valve is passing hot water out through the tundish. This only happens when the boiler is on. I have tried turning the valve into a new position, but this doesn't help.

The expansion vessel doesn't appear to have any gas in it. When you press the "tyre" valve there is no hiss.

Do I need a new expansion vessel? How much do they cost?

Thanks

 

[muggles]

It sounds like a problem with the pressure relief valve rather than the TPRV, but that's a minor point...

Your expansion vessel is the problem, however if you don't get wet pressing the tyre valve and you're sure you've pressed it fully then your expansion vessel simply needs re-pressurising. This can be done with a standard bicycle pump, check the instruction manual for the correct charge pressure.

 

[FarmerJon79]

I'm guessing that I will need to isolate the incoming supply, release the pressure in the cylinder and then pump up? Vessel says something like "initial pressure 3bar"...?

 

[muggles]

You don't need to isolate the supply, just pump it up to the required pressure, which sounds like it's 3 bar, however check the manual to be sure