Morning all
I recently moved into my present house which has a Danfoss 102E programmer. The room 'stat was a Switchmaster. Both these items are dated 1994, when the house was built. The roomstat had two wires connected. One is permanently live (when the programmer is set to heating on) and the other is a switched wire which goes live when the room stat calls for heat.
I replaced this room stat with a programmable Honeywell CM907 ( CMT 907A1041) wiring it as shown in option E of the installation instructions as a straight two wire replacement.
When I switched the mains back on, the stat behaved as expected, firing up the boiler and pump when calling for heat and switching them off when satisfied. Deep joy, or so I thought.
With the new stat in 'Auto' or 'Man' mode, when it is satisfied (room temp above target temp) the boiler and pump fire up at ten minute intervals. After about one minute the boiler shuts down.
Edit. The stat is fairly close to the hall radiator, but the boiler cycling remains even when the target temperature is well below the room temperature. The system is fully pumped with a three port motorised valve.
I have reset the stat to the factory defaults but it made no difference.
I have re-fitted the old stat and the problem has gone.
I emailed Honeywell about this but haven't received a reply.
Any suggestions before I replace the programmer and rewire the lot?
TIA
Dave
I recently moved into my present house which has a Danfoss 102E programmer. The room 'stat was a Switchmaster. Both these items are dated 1994, when the house was built. The roomstat had two wires connected. One is permanently live (when the programmer is set to heating on) and the other is a switched wire which goes live when the room stat calls for heat.
I replaced this room stat with a programmable Honeywell CM907 ( CMT 907A1041) wiring it as shown in option E of the installation instructions as a straight two wire replacement.
When I switched the mains back on, the stat behaved as expected, firing up the boiler and pump when calling for heat and switching them off when satisfied. Deep joy, or so I thought.
With the new stat in 'Auto' or 'Man' mode, when it is satisfied (room temp above target temp) the boiler and pump fire up at ten minute intervals. After about one minute the boiler shuts down.
Edit. The stat is fairly close to the hall radiator, but the boiler cycling remains even when the target temperature is well below the room temperature. The system is fully pumped with a three port motorised valve.
I have reset the stat to the factory defaults but it made no difference.
I have re-fitted the old stat and the problem has gone.
I emailed Honeywell about this but haven't received a reply.
Any suggestions before I replace the programmer and rewire the lot?
TIA
Dave