I have a Vokera Mynute 28e system boiler. The boiler does heating only. The boiler is 2 years old.
The boiler has been working fine until recently.
The gauge on the boiler shows, when cold, a system water pressure of just over 1 bar.
Lately the system has been losing water pressure. What is happening is this. The heating comes on and the gauge on the boiler slowly creeps up to 3 bar when the pressure relief valve opens and water is discharged to outside. The thermostat on the boiler seems to be working ok and shuts off the gas at 55c.
Any idea why this is happening?