Honeywell Evohome - 1 radiator not heating up

Plascebo

I have the Honeywell Evohome system installed and one radiator is not heating up (the rest of the system is working fine). The radiator thermostat seems to be working fine on the rad, i.e., it turns on when activated via the app and the boiler kicks in, but the radiator in question does not heat up. I'm "thinking" it may be an issue with the valve itself not opening and am wondering if anyone would know what the issue could be/experienced something similar?

Thanks in advance.

NewClareman

It sounds like a problem with the TRV. If you take off the Evohome head, with the boiler on, the radiator should heat.

If the radiator does heat, the TRV is ok. The first thing I would then try is changing the battery on the Evohome head. That should cause the head to recalibrate to the TRV.

Plascebo

https://www.boards.ie/discussion/comment/121313898#Comment_121313898

Thanks so much, sounds like a TRV problem all right. I recalibrated the Evohome head and tightened/loosened the valve manually and the rad did not come one (all other radiators in the house working fine). I tried pushing the pin up/down also, to no avail.

Would you know is it just a standard TRV needed or one specific to the Evohome?

NewClareman

It is a standard TRV - M30 x 1.5mm.

Wearb

Is the pin on the valve moving up and down when pressed with the blade of a screwdriver or similar? Note that the pin moves only a couple of mm.

If its stuck, you might be able to free it, BUT you could also break it and have water come out if you damage the diaphragm.