Boiler Losing Pressure- Vaillant Turbo Compact

[Mac72]

Hi,

Can someone please advise?

My Vaillant Turbo Compact has been losing pressure (0.1 bar per week) for the last 10 years! I top it up very 2 to 3 months. I have had 2 plumbers in to inspect and they cannot tell me if it is due to the boiler or a leak in the pipes under the floor.

I estimate that I am losing 200mm of water per weak. The plumber said it could be due to a leaking auto air vent or a leaking pressure relief valve or a leak under the floor. I have put a balloon over the presure relief valve and it does not collect water.

I would like to know if I could isolate the boiler from the circuit and monitor the pressure to ascertain if it's a problem with the boiler or the heating pipes under the floor. I have checked all radiator valves and they are dry.

Any help would be much appreciated.

Thanks,

Mac

 

[PhoenixServices]

Hi Max.
Welcome. Should be an easy test just to isolate the boiler from the heating circuit to work on which it is on.

Although will leave you with no heating while on test so may be better to do it during the spring.

 

[Mac72]

Thanks,

Do I need to insert any valves into the flow and return of the boiler to isolate it or is there an easier way to isolate it?

I am not a plumber but I can do DIY plumbing....thanks

 

[joni os]

Leakage is so slow that unless you disconnect and cap pipes you could not be sure isolation valves were not passing. If you have lived with this for ten years, hopefully, you keep topped up with inhibitor and all will be well until boiler replaced

 

[Mac72]

Thanks Joni,

Sounds like I will need to cap the pipes to isolate the boiler then.
I tried topping up with inhibitor but the boiler started to screach (pump I think) so I had to drain the system.

Thanks again
Mac