Flickering pressure gauge

[Rob W]

Hello, a tenant's Ideal combi 30 boiler lost pressure and shut down. An engineer re-pressurised the system, however now the pressure gauge is flickering around 1.5 bar and the tenants say the pipework occasionally becomes very noisy before quieting again. I have bled the radiators, only 1 radiator had a tiny bit of air, no change. Any suggestions gratefully received, thankyou.

[Alan Ambrose]

Double check the actual water pressure & flow at the location with something like this  

 

https://www.screwfix.com/p/monument-tools-water-flow-cup-weir-gauge/5784k

 

https://www.screwfix.com/p/monument-tools-mains-water-pressure-test-gauge-11bar/82412

 

If that's OK, there's probably a tiny leak somewhere. Check all the bleed valves for a start and all the radiator entry / exit points for signs of water. A paper tissue will give a good indication of a tiny leak. You can re-pressure yourself if you're careful, but it'll happen again if the leak isn't found. Anything changed / happen about the time the problem started? 

[ProDave]

No 1 question is where is the leak and was it fixed?

 

No 2 question is the expansion vessel okay and was it checked.

 

The 2 are very probably related.

[Rob W]

Thanks Alan & Prodave,

the tenants messaged me midday on a saturday to say the boiler wasn't working, not the best time to find someone. I contacted the agents whom found an engineer whom visited sunday am.

His report & bill to agents merely says boiler re-pressurised and radiators bled. I will see if my gas check engineer whom wasn't available on the weekend can bring the gas check forward from march.

Thankyou.

[ProDave]

So it is losing pressure but nobody has bothered to try finding the leak?