Mystery loss of pressure in Vokera Linea boiler

[JRD99]

Have been experiencing loss of pressure on Vokera Linea boiler. Over course of week pressure drops from just over 1 to near 0. Expansion vessel and PRV has been replaced, engineers haven't found any leaks in boiler itself. Engineers came to try and track leak down in pipework including lifting floorboards. Discovered small leak from one radiator and fixed it but pressure continues to fall. No signs of water damage to any floors/ceilings.

Is it possible there is a leak somewhere in the boiler out of sight?

I'm asking because we're expecting to replace boiler in coming months. Wondering if I should do that before starting a fresh round of tearing house to pieces trying to find the mystery leak?

Thoughts welcome.

 

[PrenticeBoyofDerry]

Is there any evidence of leak coming from boiler? Is the boiler discharging water out side via blow off? There could be other leaks on the central heating system, I would check around all visible valves such as radiator valves, bleed offs and radiator end caps also check any drain off valves are not weeping.

 

[AlanE]

But when does it loose pressure - all the time, just when running?

If you repressurised boiler and left it overnight switched off does pressure drop?

When running what does the pressure rise to?

Tie a polythene bag over the pressure release pipe - does it collect water when the pressure drops?

All relevant, and important, questions when trying to diagnose pressure drops.

 

[algas]

Pressurise your boiler to 2 bar the last thing before going to bed or first thing in the morning but it has to be cold, isolate your boiler with the valves on the flow and return. Without using the boiler for say 6=8 hrs re check the pressure if it is still 2 bar it is likely the instalation, open the iso valves if you get an imediate drop then you know its the instalation.

 

[scatmanjohn]

Has the main heat exchanger been checked? Very common for these to leak.