One underfloor heating zone wont heat up

[Temp]

On 02/01/2021 at 19:33, Temp said:

I think its possible to have full flow even with air in the pipe. The air bubble acts like a narrowing of the pipe so water moves faster while going past it.

 

[paud100]

Hopefully it’s air in the system but Joule engineer tells me that they’d see flowmeter indicator bobbing up and down a bit if it was air?? Would that really be the case?? 
 

Thermostat calls, valves open at manifold and supply and return feel warm once valve opens. But thermostat only gets to about 22.3 degC (but floor is still really cold compared to hallway right beside it) and it seems it can’t get room any hotter than that temp. Because it can’t reach set point of about 23deg it keeps calling for heat and it’s only thermostat in house that keeps air to water pump running outside then. That’s driving electricity bill through the roof but rooms still can’t get warm. 
 

im really hoping it’s just air.

 

Rest of house is perfect, floor nice and toasty etc.  

[TonyT]

Isn’t there just one circuit of UFH off the manifold as you only have one pair of pipes as shown in the picture posted in the 3rd January 

[paud100]

There are 2 loops feeding sitting room which is the problem room. These are the 2 loops on right hand side of manifold in attached picture. 

[TonyT]

apologies I was looking at this one!!

[paud100]

That’s from JeffR, not me. Would be really interested to hear if JeffR got sorted in the end and what the problem was…. 

[Temp]

8 hours ago, paud100 said:

Thermostat calls, valves open at manifold and supply and return feel warm once valve opens. But thermostat only gets to about 22.3 degC (but floor is still really cold compared to hallway right beside it) and it seems it can’t get room any hotter than that temp. Because it can’t reach set point of about 23deg it keeps calling for heat and it’s only thermostat in house that keeps air to water pump running outside then. That’s driving electricity bill through the roof but rooms still can’t get warm. 

 

Has this loop ever worked? Eg did this floor get noticeably warmer last winter? 

 

Sorry if obvious but.. Do you have carpet in both sitting room and hall? We have a mix of carpet wood and stone and they feel quite different when working normally.

 

8 hours ago, paud100 said:

Hopefully it’s air in the system but Joule engineer tells me that they’d see flowmeter indicator bobbing up and down a bit if it was air?? Would that really be the case??

 

If the flow meter says there is flow and it worked before I can't think of anything else it can be. 

 

Sometimes an actuator pin gets stuck or the actuator pops up off the valve, but if you see the flow meter changing and the return pipe gets hot it can't be something like that.