Vaillant Turbomax strange pressure loss pattern, HELP!

[robw]

Hi all

Any advice welcomed

I have a Turbomax VUW282 that is loosing pressure fast when my ground floor loop is on but only very slowly when just my 1st floor loop is on (boiler on 1st floor), I set pressure to 1bar cold and it can drop to 0 cold in less than a day. Pressure when in use is quite high 2.6-2.7, at what pressure does the release valve trip? Although nothing is coming out of the overflow, it has in the past but not for a long time. I have checked the CH system twice, been under the floor and there are NO leaks anywhere at all.

The differential pressure switch is well coroded could this be my problem?

The air release valve also looks pretty suspect

I do know my way round the boiler to an extent but would not call myself an expert, in the past I have replaced parts myself without any problems including the DHW heat exchanger and the diverter valve.

Cheers
Rob

 

[ChrisR]

CHange the AAV, and the stop the diff valve leak - however you do it.

Do the procedure wot I rote in the FAQ section on the pressure vessel see "Boiler Pressure Problems".
Relief valve should open at 3 bar. They can leak unnoticed when hot - the water evaporates.
Check all rad valve stems for signs too - again the leaks evaporate.

Run at 1 - 1.5 bar, and come back if problems persist having done all the above.