Central heating at home: one of the heaters wouldn't emit heat

[Mazonas]

Hi,
first of all I would like to explain the situation in order to possibly help you determine what could cause the problem.
The central heating and the heaters are fairly new, everything has been fitted 5 years ago. Heating is turned on very rarely.. just a few times a year (mainly during winter months).
So for remaining 9 month it would be off. The last time heating was on - all the heaters were working fine. However I turned it on yesterday (after 9 month gap) and one of the heaters wouldn't emit heat at all (nor at the bottom nor anywhere). Thermostatic valve is turned on to the fullest, lockshield also. Water supply reaches the heater (as after barely pulling the hose, that is connected to the lockshield, out you can see that water starts dripping).

I don't understand why would it stop working out of nowhere. Since no adjustments or any work have been done to it since the last time its been used. And last time it worked fine.

Also, I never knew till now, that you need to bleed heaters on a regular basis? I have never bled them in 5 years. Could that be the cause?
Thanks for any info

[dewaltdisney]

It is more than likely the thermostatic valve, what happens if the valve is turned off in summer the pin can get locked into position. This video explains how to try to free it https://www.youtube.com/watch?v=dULHUbLsRGY

DWD

[ericmark]

With my eQ-3 TRV heads, midday every Saturday I hear them exercising, and the instructions come up with fault code F3 if the valve is not moving, I would say cheaper models don't do this, but the bluetooth version cost me £15 each in 2019.

My Energenie Mihome TRV head you can program when it exercises. It does not show over or under travel, Kasa TRV head shows E1 if not resistance found, and E2 if not travel.

Batteries (2 x AA) last the year, can last 2 years, I change every year to be sure.

[Mazonas]

It is more than likely the thermostatic valve, what happens if the valve is turned off in summer the pin can get locked into position. This video explains how to try to free it <span class="skimlinks-unlinked">https://www.youtube.com/watch?v=dULHUbLsRGY</span>

DWD

Indeed it was. It took 5min to fix. Very helpful. Many thanks.

[Mazonas]

During non heating period (in my case I dont heat house once the winter ends till the next winter starts), whats the best position to leave thermostatic valve and lockshield valve at in order to avoid any issues?

[dewaltdisney]

Leave them on 5, which is fully open. I would leave the lockshields alone.

DWD

[Mazonas]

Thank you. I will follow your advice and this is what Im going to do.