Vaillant 828e pressure drop if heating switched off/on

[GibsonGoldTrim]

We have a Vaillant 828e which from new gradually reduces pressure if I set the heating to go off at night and on in the morning, a plumber has said that this is to be expected, but as the boiler is in the attic it's not the easiest thing to keep an eye on. if I leave the heating on all the time the pressure stays ok!

Any ideas greatly appreciated.

Pete.

 

[Mozza00]

Pressure variations are normal with hot-cold cycling and for your boiler the range should be between 1-1.5 bar.

 

[GibsonGoldTrim]

Mozza00 - Thanks for the response, unfortunately the pressure continues to drop until I have to re-pressurise the system. If I leave the heating on there is no pressure drop.

 

[bobw1956]

Your pressure drop is not to be expected,you have a leak somewhere,check the pressure relief pipe which exits outside,then the rest of thye system.