Hi,
When my boiler has heating on the pressure on the boiler goes up to 2 (this apparently is OK). But when I turn the heating off and leave overnight the pressure rises to 3 1/2. As a result of this I have to bleed the radiators to reset the pressure back to 1.5.
Is there any reason (what can be done) to resove this.

Thanks
Daffydd.

Daffydd, October 2006

Make sure that your filling loop valve is not left open. Disconnect the loop to verify that it is not passing. If the pressure increase is not coming from there then you may have a burst heat exchanger. This allows water from the domestic side (mains pressure) to pass to the central heating sealed system.

kenneth, October 2006