UFH problem solving

[Bozza]

Ok so my UFH is not working in my study.  Works elsewhere fine.  Actuator is open & working (gets hot) but flow gauge is low and pipes are cold.  study circuit is circled yellow in picture.  Please note in this pic I’m only trying to get the UFH in the study working.  Plumber thought it was an electrical problem but electrician has confirmed no electrical problem, this is consistent with the actuator opening in line with turning heating on/thermostat settings.  So I think we’re back to it being a water/plumbing/flow/pressure type  issue.

 

I know there will someone here have a good idea what the problem is.....

 

 

 

 

 

 

 

[ProDave]

Have you tried opening the flow meter to increase the flow?

 

Have you unscrewed that actuator (which will have the effect of turning that circuit on) to be sure it is releasing properly.  The exposed pin on the manifold should spring up, sometimes they can stick.

 

Are you sure the manifold pump is running?

[Bozza]

Cheers ProDave,  not being a plumber I’m a bit reluctant to fiddle too much, especially as the plumber has already attended so I presume he covered the basics.

 

in response to your suggestions I’ve turned the flow gauge anti clockwise a bit, but the liquid gauge remains low.  The actuator black pin on top rises and falls when I turn the heating on / adjust thermostats accordingly and gets warm when “on”.  But I haven’t fiddled with that any further.  I’m pretty sure the manifold is working fine as the UFH works in all the other rooms.

 

 

 

 

 

 

 

 

[Nickfromwales]

Does the return pipe get warm as well as the flow? If not, it’s air-locked. 

[Bozza]

3 hours ago, Nickfromwales said:

Does the return pipe get warm as well as the flow? If not, it’s air-locked. 

No both pipes are cold.  If it’s air locked I take it that means bleeding that circuit, like you would with air in a normal rad?

[Nickfromwales]

3 hours ago, Bozza said:

No both pipes are cold.  If it’s air locked I take it that means bleeding that circuit, like you would with air in a normal rad?

Not quite. 
Shut the system down and turn the power off. Then, take the actuator head off the loop in question.
Then use the filling loop to pressurise the system to 2.5bar. Open the drain off so water is free to leave via the return of the air-locked loop, and, before the pressure bottoms out at zero, you open the filling loop so you keep blasting cold mains water through the loop and out to drain.
That should have enough velocity to blow the air out and have the loop completely occupied by water only.

Shut the drain off and close the filling loop simultaneously so the system pressure stays above 0.5-1 bar, Power back up and check for flow ( heat ) and let us know the results. 

[Nickfromwales]

Forgot to say you need to depress the pin to allow flow when the system pressure is up. 
D’oh. 
You’ll hear the water rush through and that needs to flow for about 3-5 mins. Air should be visible coming out of the hose with water, which will then eventually run quiet. 

[Bozza]

Nice one Nick.   Had been checking YouTube and came across a video which basically is same as what you’ve advised.  At no cost to me the plumber is back on Monday, so I’ll get him to do it as you suggest if he doesn’t suggest this himself.