Oil fired UFH system. Worked faultlessly for 5 years until now.
The rooms are individually controlled by room thermostats. One of our rooms is not heating up and noticed
The 2 thermo actuators for the room are not opening when the stats are calling for heat.
Any ideas??

Are the actuators on the manifold?

Have they seized after a summer of inactivity? Why two actuators – do you mean two circuits in one room? Or one actuator and one manual lockshield on the manifold for the room?

Can you open the actuators manually?

Are the thermostats wireless? Are they still paired with the receiver correctly? If they are wired can you use a multimeter to check that they close the circuit at the wiring centre?

Yes the actuators are on the manifold. It’s a fairly large room so two circuits in the one room.
Not sure how to open them manually.
The thermostats are wired.

Check the obvious first – batteries in the stat?

I dont have manifold actuators nyself, but Im going to guess that they have a screw down collar that holds them down on to a valve pin. If you remove them then the valve should be wholly open. Does that sound familiar? You should be able to then check that the pin lifts properly (is not seized) and of course check that hot water flows too.

If that isnt the problem then you need to check the thermostat closes a contact at the wiring relay with a multimeter. But only if you are competent with mains electrics.

boring bear 😉

Yes stoner I have screwed the gold collar off and took the actuator off. The horizontal pin sticking out is not moving, should this pin be able to lift out?

horizontal?

The valve pin should be poking out of the middle of the valve body mounted in the manifold. You should be able to push it in, and then it should be able to spring back out again.

Lol stoner sorry I meant vertical!
The pin seems to be stuck, is it safe to try and move it with pliers, bit scared to force it!

I reckon it’s safe if youre not hamfisted.

First try and push it in, maybe with the help of a hard object – dont over do it.

If it doesnt go in, then try and lift it with a pair of pliers.

Again, I cant vouch for your mechanical sympathy, so dont be a gorilla 🙂

Took both actuators apart freed off the sticking pin and gave them both a good clean.
Dialed in some heat on the room stat and bingo both actuators opened.
I don’t think the UFH in this room has been used much as we have a log burner in it so possibly caused by lack of use.
Thanks for your help stoner

P.s. do these systems need any maintenance? It’s never been touched in 5 years

Good news.

I dont know about maintenance, bear has much more experience so may be able to offer some advice based on years of knowledge.

I guess keeping on top of the inhibitor concentration in the system and maybe considering one with a biocide too?
Maybe override the thermostats a couple of times a season to make sure the valves are used.

And of course change the batteries in the thermostats 🙂