Ravenheat csi85T - CH comes on when set to HW only

[jackowen]

My CH is coming on even though the boiler is set to HW only.

It seems to come on randomly throughout the day and night. The fact that it comes on in the middle of the night makes me think it is not linked to HW i.e it doesn't come on when HW is running. So maybe 3 way valve is ok.

My thoughts are it is maybe the timer.

Does anyone have any thoughts, before I order any parts.

Cheers.

 

[gas4you]

3 way valve faulty and boiler firing up for DHW pre-heat at what appears to be random times.

 

[jackowen]

Thanks for that Dave. I'll check the 3 way valve.

 

[jackowen]

Just one more question. If the heat is coming on during DHW preheat, would it not also come on when HW is running? that isn't happening.

 

[gas4you]

Yes, I would have thought so

 

[mr-crs]

I had this same problem turned out that the divertor leaked slighty from the pin and shorted the micro switch out causing the boiler to fire up, as the divertor was in ch mode it heated the rads. There is no pre heat on the hw on this boiler so I would check the micro switch first.

 

[jackowen]

Thanks for the advice guys.
I think I'll just order the microswitch for now, as they are pretty cheap. Hopefully that will do the trick and i won't need to order the more expensive parts.
i'll let you know how I get on.