I would appreciate some help with a Ravenheat csi85, 2yrs old. The HW works fine but the CH is malfunctioning.
On selecting CH the pump and fan run, the burner lights then the fan stops after 5secs and the burner goes out 4secs afterwards. This cycle repeats indefinitely with the burner switching on for 7-9secs then going out for 10-15secs.
The timer/room thermostat/valves are all calling for heat (linked out), the pump runs fine, fan runs normally, no obstruction in the flue, both CH and DHW sensors register about 20k ohm cold, the overheat thermostat has continuity across it (0 ohms). The APS tubes and venturi are clear, APS switch clicks on blowing tubes. No air in the system. Condensate drain clear (and no sensor anyhow).
Whilst running the fan is getting 240v and the APS has an input of 15vDC and an output of 0.8vDC with the fan off and 1.4vDC with the fan on.
I don't understand how the HW works fine on demand (burner and fan on coninuously) but something is obviously switching the fan and burner off when the CH is activated. I've tried rotating the venturi collar 90degrees (previous post) but no change.
I tried ringing Ravenheat on friday - engaged all afternoon. Any ideas much appreciated. Thanks
On selecting CH the pump and fan run, the burner lights then the fan stops after 5secs and the burner goes out 4secs afterwards. This cycle repeats indefinitely with the burner switching on for 7-9secs then going out for 10-15secs.
The timer/room thermostat/valves are all calling for heat (linked out), the pump runs fine, fan runs normally, no obstruction in the flue, both CH and DHW sensors register about 20k ohm cold, the overheat thermostat has continuity across it (0 ohms). The APS tubes and venturi are clear, APS switch clicks on blowing tubes. No air in the system. Condensate drain clear (and no sensor anyhow).
Whilst running the fan is getting 240v and the APS has an input of 15vDC and an output of 0.8vDC with the fan off and 1.4vDC with the fan on.
I don't understand how the HW works fine on demand (burner and fan on coninuously) but something is obviously switching the fan and burner off when the CH is activated. I've tried rotating the venturi collar 90degrees (previous post) but no change.
I tried ringing Ravenheat on friday - engaged all afternoon. Any ideas much appreciated. Thanks