Ravenheat 820/20T - CH Not working.

[GodKnows]

Hi all,

Got pilot on set controls to CH, boiler fires up for about 25 secs, then cuts out, pilot remains lit. Checked pump running on low speed then high speed ok. Overheat stat not cutting in, as pilot remains lit, checked high limit stat that has continuity ok. Boiler making a kettlying noise! when fired up, checked AAV to see that it was open one full turn, OK.

Must be some stat or something, as 2/3 mins later boiler fires up again for around 20-25 secs, then shuts down again, when CH in demand mode.
Could it be that the heat exchanger is blocked. Had the diverter valve changed around a month ago, as no DHW was forthcoming, but, had CH
Works fine in DHW Mode.


Any takers

 

[Agile]

It sounds as if the flow is restricted on the CH.

That may be a blocked or weak pump or perhaps the heating circuit is blocked or restricted.

Just possibly the diverter manifold section is not following the hydraulic unit.

Easy for a boiler engineer to identify on site but rather difficult over the internet.

Tony

 

[Timmyturtle]

Just looked at one of these boilers and found it to be seriously clogged in the heat exchanger.
going to powerflush and probably then a new boiler as doubtful it will clear