Heating stays on

[aquadyte]

HI new to this forum and looking for some assistance.
I have a oil fired heating system with 2 underfloor heating zones, one of which was re routed a few years back.

One of the zones has developed a fault recently with the heating staying running on all the time even when I turn the control unit off.

The control unit is a Danfoss TP5000 battery operated room thermostat. Batteries are fine and have been replaced to make sure.

The only way I can turn the heating off in this zone is to either turn the mains supply of (which controls everything) or remove the Danfoss unit from the wall.

I suspect the Danfoss is faulty rather than the pump but could be wrong, is there an easy way to find out.

 

[gaspro1981]

It's likely that you have a zone valve that has failed it would be beneficial to those trying to offer advice if you could post some pics of your present set up

 

[aquadyte]

Thanks Gaspro. I have added 3 photos, 2 of the valve and one of the timer/thermostat.
when I disconnect the timer the valve closes, I can also operate the valve using the lever at the bottom with no restrictions (not sure if this help)

Is there another way to test the valve?

View media item 49803 View media item 49804 View media item 49805

 

[gaspro1981]

There should be resistance on the lever of the actuator when the thermostat or power supply is off is this the case ??

 

[aquadyte]

Yes and when I release it springs back.

 

[gaspro1981]

The syncron motor in the actuator only drives open when there is a power supply to it if with the power supply on and the thermostat set to off and the lever on the actuator is still stiff to operate I would argue that is a thermostat problem
Do you have any experience with using a mains tester or multimeter in a safe manor ??
Can you identify where the cable flex from the zone valve goes to ?

 

[aquadyte]

No afraid not, however a luck has it I have an electrician due in a couple of days to fix some lighting, I'll ask him to test for me and will post what he advises.

Many thanks

 

[gaspro1981]

The syncron motor in the actuator only drives open when there is a power supply to it if with the power supply on and the thermostat set to off and the lever on the actuator is still stiff to operate I would argue that is NOT a thermostat problem
Do you have any experience with using a mains tester or multimeter in a safe manor ??
Can you identify where the cable flex from the zone valve goes to ?

Sorry

 

[gaspro1981]

Shouldn't take to long for the sparks to identify the problem

Good luck