Danfoss FP715 - stay's on

[CliveP]

My Danfoss FP715 programmable heat and water control, is stay on for both heating and water. The option to select Auto (timed on off) all day or off has cease to turn off the unit keep our oil burn in full on mode. Have use reset no impact

 

[stem]

It is unusual for the programmer to cause a problem like this. Usually it is a motorised valve that the programmer and thermostats are controlling that is at fault. But that will depend upon the design of your heating system. Most but not all have motorised valve(s)

If the programmer was faulty and stuck 'on' 24/7 the room thermostat and hot water cylinder thermostat would still be able to control the heating and hot water. Can they?

Usually when a programmer is stuck permanently on, it is because there has been a short circuit somewhere and the internal switch contacts have welded together, but you would know if that was the case.

 

[ianmcd]

if your radiators and HW are still heating and the boiler is not locking out with an over heat fault then it is a motorised valve fault and not the programmer

 

[oilhead]

If the neon goes on and off with the change of programme modes, then agree with the above. If it does not, then it is possible for the unit to fail. The FP715 only has a switching capacity of 3amp which can be a little low for an oil boiler, causing premature failure.