How do I lower the pressure on a combi boiler?

Hi Sarah, Had same problem with Baxi Combi Instant 105e yesterday. I had closed the valve on the Filler loop (which on mine was a red plastic knob on a braided flexible pipe) but the valve was obviously not closed properly. I could hear a faint buzzing noise when I put my ear to the braided loop even with the system switched off. I had to open and close the valve several times quickly before the noise stopped. The pressure relief valve then automatically cut in and dropped the pressure from 31/2 to 21/2. Hope this helps.
Frank

Frank Heron
March 2008

Take the pressure out of the boiler when it cold, take it down to just over 1bar. Then find the stop cock for the house and turn it off, now run the boiler on CH and see what happens to the pressure? The pressure should rise to no more than 2 bar when hot, and will drop back to 1 bar when cold. If this is the case and the pressure stays at these levels with the water to the house switched off, then mains water must have been leaking through the filling loop or the plate heat exchanger.

Justin
March 2008

Hello Sarah, it sounds like you have left the fill loop valve open, the first thing you need to do is close this.
What boiler do you have

gary.wright53@googlemail.com
March 2008