My relative has a system boiler which operates fine.(Vokera) When the boiler is cold the pressure on the gauge drops to zero so naturally you would think there is a leak so top it up to 1bar pressure however if you put more than a cup full in when the boiler fires and it begins to heat up the pressure builds up and the safety valve opens and expels the water to the outside and returns the pressure to max 1.2 bar.
On cooling the gauge shows zero pressure.
The system is fully filled and vented no air .
If the boiler fires at zero pressure (on the gauge) the pressure rises to max 1.2 bar on heat and hot water hot water or heating only and works fine.
The safety valve operates perfectly,the pump runs fine and is vented but this gauge shows zero on cold. Any ideas what this could be.
On cooling the gauge shows zero pressure.
The system is fully filled and vented no air .
If the boiler fires at zero pressure (on the gauge) the pressure rises to max 1.2 bar on heat and hot water hot water or heating only and works fine.
The safety valve operates perfectly,the pump runs fine and is vented but this gauge shows zero on cold. Any ideas what this could be.
