Vaillant Turbomax increasing pressure...

[David937]

Hi there,

9 year old Vaillant Turbomax Plus..pressure keeps on increasing to just over 3 bar till the PRV is opened, this happens quite slowly over a few hours even if the heating is off, PRV opens and pressure goes back to 1.5-1.8. Expansion vessel has been checked and is at the correct pressure. I have a feeling the valve on the filling loop is at fault because if you turn it completely clockwise you can still hear a little bit of water entering the system and the pressure still rises, if you turn it completely anticlockwise the same happens but if you leave it in the middle i.e not completely clockwise nor completely anticlockwise you cant hear any water going in, however seeing as the pressure increase happens quite slowly I still think the filling loop may well be letting by.

Does this sound plausible enough?

Could I check it by shutting off the isolating valve on the cold water inlet and seeing if the pressure goes up? This wouldn't be ideal though as heating is needed!

Thanks.

 

[Egga]

Youre on the right track. It sounds like filling loop is passing. Could also be plate heat exchanger pinholed.

 

[doitall]

As above, except the filler loop should be disconnected.

 

[David937]

As above, except the filler loop should be disconnected.

Hiya, I'm not quite sure what you mean; the filling loop is built in, you just need the key or a flat screwdriver to open or close it.

 

[Adrian13]

a number of filling loops hang below the boiler allowing you to disconnect the pipe from feeding the boiler, if the case this will stop water flow into boiler and allow you to confirm the water inlet constantly flows.

If filling loop is located internally, sounds like front of boiler needs removing to support similar process, but let the pros on here provide the right info for that step.