problem with hot water zone

[smudger12]

Hi

I have a vokera boiler and it has been fine for 5 years. I have 4 zones: downstairs CH, Upstairs CH, underfloor heating and Hot Water. The Hot water runs through the immersion tank. The system in sealed and it is topped up from mains water. Recently the boiler has started making groaning (shuddering) noises coming from the heater when on hot water zone is on alone. Its fine when any other zone is on. To me this suggests that the boiler is ok (because no noise when other zones are on) and that there is something wrong with the hot water zone.

To add to the history, the boiler broke about 2 months ago - would not ignite and zero water pressure. This was fixed by replacing electrodes. Noise started straight after this. I have since added cleaner, flushed out and added inhibitor. No difference.

I have had 3 plumbers look at the boiler and system and none have been able to find anything. Last one suggested I replace the boiler

So two questions:

1) What can be wrong?
2) If I have to replace the boiler, what one should I go for - I want efficiency and no hassle?

Thanks

Smudger

 

[Sharp Point]

Whats the model of the boiler?

here's a few things for you to mull over,

1)is the boiler still modulating( burner getting bigger and smaller....in a nutshell) could be a faulty gas valve i.e full flame.
2)is there a restriction on hot water circuit, partly open zone valve or blockage, half shut regulating valve.
3)a stuck open auto bypass in boiler
4)a fouled up cylinder coil .......see number 2
5)Pump struggling due restriction.......see number 2
6)Pump just tired....
7)Fan tired ??? pure coincidence
8) partially blocked spirovent dirt separator........and yes they do get blocked peeps, contrary to there sales reps!!! or magnaleak's.

And may i add, being flushed out doesn't necessarily mean the system is going to be clean, hard baked sludge is a tw@t to remove with even the most aggressive of chemicals.

hope that helps..

 

[smudger12]

Hi bogrodder.
No 2 appears to have been the problem. I've opened up the valve ino the cylinder a bit more and noise has gone ( possibly temporarily?)
Thanks a million
smudger

 

[Sharp Point]

Hi bogrodder.
No 2 appears to have been the problem. I've opened up the valve ino the cylinder a bit more and noise has gone ( possibly temporarily?)
Thanks a million
smudger

superb!