ufh actuator stuck closed?

[nedoakley]

Hope someone can help me with a problem one wwith one of the 2 zones on my ufh system.one(downstairs)works fine,the other(upstairs bedroom)fails to heat up.
I've had room thermostat checked and its fine.thought it could be actuator stuck closed.i took top off but pin appears to be up-does that mean it should be open?
I also thought it might be a fault with pump but if i feel the pipes i think i can feel water flowing? Any thoughts would be appreciated
p.s. I'm not a plumber (joiner)

 

[joe plumber]

if you remove the actuator and let the system run does it heat up then? are both zones on the same manifold? if not have you checked the valve to the upstairs manifold, is it opening?

 

[nedoakley]

Hi joe
thanks for taking time to help.i took off actuator head but loop does'nt seem to be warming up.the pin is not fully out compared to ones on loop thats ok.both are on same manifold

 

[joe plumber]

sounds like the pin could be stuck. ive never done it on a ufh manifold but i know with trv's if the pin sticks you can some pliers on it and gently move it. maybe try that just be gentle with it

 

[mountainman]

sounds like the pin could be stuck. ive never done it on a ufh manifold but i know with trv's if the pin sticks you can some pliers on it and gently move it. maybe try that just be gentle with it

If the UF valve works on the same principle as a trv then the pin isn't attached to the valve.
Give it a wallop or two from a hammer and that should sort it out.

 

[nedoakley]

Now theres 2 different approaches! i gently lifted pin with pliers but it then returns to its half raised position

 

[stevetheplumber]

if its the same as trv's which i would imagine it is i would tap down on the pinor tap the manifold roughly where the valve seat would be

 

[nedoakley]

Is it possible limescale is causing a blockage as i live in a hard water area.how difficult would it be for a plumber to check this?pin seems to move freely but always returns to halfway position.
Could i swop actuator head with one on other loop thats ok to check if theres a wiring fault?

 

[SimonJohns]

Ufh valves usually work the opposite to trv's.

If your pump is running and heating is on, press the pin down. Hold it there for a few mins and see if everything warms up

The actuator will usually have a tell tale window to tell you if it is open or closed

There may also be a flow meter that will let you know if there is any flow

Got a photo of your manifold?

 

[nedoakley]

Heres a couple of pics.pin doesnt want to push down.other ones on working loop are fully out.