I have a underfloor heating system installed in my apartment.
Each room has a Uponor T-37 thermostat, hooked up to C-35 controller.
The system is about four years old and recently I have noticed a regular clicking sound from the relay in the controller unit.
At thermostat side, when I turn the dial so I can heat into the room, the LED comes on, then after 5 seconds or so it turns off. The light then comes back on again after a half-second or so. This cycle repeats, and seems to happen simultaneously at each thermostat in every room/zone.
I assume this is bad for my boiler/heating system because it's receiving a command to supply heat on/off every few seconds.
Any ideas on what could be wrong?
I've tried to turn-off power to heating system and boiler for a few hours, thinking it might reset any fault.
I was worried about taking off the cover off the control unit incase there maybe a danger of a shock. I removed the cover of the thermostat and noticed that as the LED switches off, it flashes rapidly.
I'm in the process of calling in a plumber/heating technician, but just thought I try and do my own research on the matter to see if there is an easy fix. Hoping it won't be an expensive repair.
Best Answer
I called a number of Central Heating contractors and also Uponor, the company that makes the controller.
I was told that the clicking noise comes from the soft-fuses inside the controller trying to reset. They said box has failed and needs to be replaced by an electrician. Since the controller is the simplest model in their range, there are no diagnostic LEDs or other features that indicate a fault status, except the clicking noise of the soft-fuse.
The repair should only be about an hours labour plus cost of a new controller box.