Combi boiler not holding pressure

[RrogerD]

Hi. I've now visited the property. The mentioning of the hot-water is a red-herring.

Turning the flow inlet, bringing the pressure back up to 2bar or so, the needle literally creeps down. No heating on and no water running.

I fear this could indicate the worst, a leak in the heating pipework and, as nothing visible around the rads and so far, no stains on the ceilings, then presumably the only hidden area, under the suspended ground floor somewhere.

Are there any other possibilities before I start organising having the tenant move out and ripping up floors?

 

[RrogerD]

Hi. I've now visited the property. The mentioning of the hot-water is a red-herring.

Turning the flow inlet, bringing the pressure back up to 2bar or so, the needle literally creeps down. No heating on and no water running.

I fear this could indicate the worst, a leak in the heating pipework and, as nothing visible around the rads and so far, no stains on the ceilings, then presumably the only hidden area, under the suspended ground floor somewhere.

Are there any other possibilities before I start organising having the tenant move out and ripping up floors?

Would there be an internal drain system through the condensate pipe?

 

[ianmcd]

Would there be an internal drain system through the condensate pipe?

It is a possibility that your heatexchanger is pinholed, unusual but does happen, to test turn heating and water both off, set pressure to between 1.5 to 2.0 Bar no higher, disconnect the condensate hose below the boiler and put into a bowl if the heatexchanger has pinholed then water will accumulate in the bowl, do not run the boiler while doing this test

 

[RrogerD]

Since writing the above I have spoken to Baxi tech support who suggested isolating the flow and return and bring to pressure. If it drops then boiler fault, if not, then pipework fault.

I did this. Pressure stable therefore sadly it seems pipework leak. However.....

When I opened the valves again, the pressure still remained stable. I fired the boiler with the HW and all ok and ran the CH, still all ok, for a good ten minutes.

Could it be dirt in the flow/return taps? What would cause this symptom?

Unfortunately, 1hr later I get a message from the tenant, the pressure has dropped off completely again, to zero.

Is this something going on with the boiler valves? If I were to be getting a dribble from the condensate pipe, what would this signify (I thought I was seeing it but may be just wishful thinking. Maybe, maybe not)?

I'm not a plumber or heating engineer, just trying to muddle my way around sorting this before pulling up floorboards, possibly unnecessarily.

Thanks

 

[ianmcd]

An old trick if you have a magnetic filter fitted its easy to do it with that, get some cheap perfume or after shave and put some in the system water and sometimes you will smell it in the room where the leak is doesent always work but if the pressure is dropping that fast it probably would, just narrows it down when trying to locate a leak

 

[RrogerD]

An old trick if you have a magnetic filter fitted its easy to do it with that, get some cheap perfume or after shave and put some in the system water and sometimes you will smell it in the room where the leak is doesent always work but if the pressure is dropping that fast it probably would, just narrows it down when trying to locate a leak

That's a very useful tip. Thank you.