Can anyone tell me if it's normal for this system to have a variation in pressure of as much as 1.3bar during normal operation. Starting from cold at 1.1bar and after a demand cycle the pressure registers at 2.4bar and even triggers the pressure release valve (although it's suppose to do that at 3bar). The pressure then gradually decreases over a period of time (roughly 30mins to 1hr, provided there's no demand) until it settles at 1.1bar again.

Frank, November 2008

Sorry Frank
No answer, just another pressure question relating to the 30SXI........
My central heating system doesn't retain pressure, no visible leaks on radiators or visible pipework etc
BUT
the overflow pipe from the boiler releases water slowly!

Code F21 within the Glow-worm booklet states...
PROBLEM....Lack of water fault (pressure is less than 0.5 bar)
POSSIBLE CAUSE....system leak or faulty pressure sensor

SO........my boiler works but I have to add water every day, is the problem a faulty pressure sensor which allows/forces water out of the system via the boiler overflow pipe or something else

Henry, March 2009