Danfoss thermostatic radiator system issue

cangk

I oversee an apartment community that has the Danfoss thermostatic radiator system.  We have a wall mount thermostat 013G8562, which controls the temp.  There is a wire that connects from the wall mount to the sensor in the radiator, there is no power to the wire, but we seam to have to replace the thermostat and the sensor, why???? if there is no power from or to these two items, why are they not working?

Paul48

Controls

The boiler must operate on a reset control. It must shut off and the boiler pressure must go to zero. If the boiler just cycles on pressure, they will not work.That is not a wire. It is a capillary tube, and care must be taken to not kink it.

Rod

Danfoss 013G8562 TRV Remote

Hi-  These units don't operate on electricity. I haven't done one of these in a while but I believe the "wire" you are referring to is a capillary tube which would mean it is important not to bend or kink it. I've attached the instruction sheet that comes with the Danfoss 013G8562 remote and if you notice the diagram in the bottom left hand corner of page 1, it mentions a minimum radius of 10 inches on bends so in leading the capillary tube from the valve on the radiator to adjustable control box any bends made should be wide so the tube isn't kinked. The Danfoss 13G8562 comes as a complete unit and is available from Pex Supply http://www.pexsupply.com/ on the internet or your local heating supply.

Do you have other units of this type in the building and are they working properly?

- Rod

Paul48

......chicken or the egg

This sounds stupid, but, even if none work, only the apartments that overheat have a problem, and that may have nothing to do with the TRV. Really need to know how the boiler is controlled.

cangk

Danfoss 013G8562 TRV Remote

We have several communities that have this same set up.  Our thermostat is attached to the wall,  The capillary tube is connected to  the termostat and then goes behind the wall to the register, which is then connected to the sensor.  I am told that the thermostat and sensor are the items that go bad.  Could it be that it is the capillary tube that has gone bad?  Maybe someone how it has been pinched? 

Paul48

Anything's possible

If the failure rate seems excessive, contact the manufacturer. They would be able to disect their product, and tell you what caused the failure.

Rod

Danfoss 013G8562

LOL!  Paul is about two questions /answers ahead of me! If this is a one pipe system, to allow a 1 pipe TRV to operate properly, as he mentioned, there has to be a means to shut off the boiler periodically so that the pressure can go to zero and allow air to reenter the radiators. 

Kinking and/or pinching the capillary tube is a "no-no"! Otherwise these units are reasonably long lasting.

- Rod

Paul48

I'd

still bet the boiler is set-point control, and they are not failing.The problem will rear its ugly head, as outdoor temperatures get more moderate.