I Have a Baxi combo 105 boiler with a mind of its own!!. The boiler gauge is very irratic. It can drop over 1 bar then after topping it up and hour later reads 1 bar more that previous. Do I ignore the gauge or keep topping the system up. I have looked for obvious leaks etc. but all seems ok. The system is working fine only the guage problem.

Have just checked the outside pipe and there are signs of a slight drip. The boiler is located in the garage, do you think the current low temperature could be anything to go by?. I have checked the gauge fairly regularly but have never noticed a fluctuation like this.

If you top the boiler pressure up to 1.2 bar when cold, how high does it goes when you turn the boiler on.