Boiler Losing Pressure when central Heating switched off Help and information on all topics relating to your central heating, air conditioning and ventilation issues.

[apm0407]

I recently had a new pressure release valve fitted and but now when the boiler is switched off the pressure keeps dropping to Zero

[DEEARR2]

When you recharge the system to around 1.25 Bar cold, does the pressure hold. If it does then monitor the operating pressure as the system starts to heat. It should rise by approx 0.5-0.75 Bar during operation. If the pressure rises to around 3.0 Bar then water will be discharged via the PR valve and will result in low pressure when the boiler switches off and cools.