Underfllor heating return not getting up to temperature.

[Tag]

Hi I have a underfloor heating that is has a very Luke warm return temperature coming back from the pipes.

The flow pipe is very hot.

The house is taking over 7 hours to get to temperature.

Any hints or tips pls will be much appreciated.

Thanks

[SteamyTea]

How much insulation is under the floor, could be energy just leaking out to the ground.

But fill us in with more details.

Size of heated floor area, on how many floors, are they zoned separately, what type of heating system is it.

[ProDave]

It sounds like the flow from the boiler (or other heat source) is way too low.

 

Obvious question, is this new? and has it ever worked properly? or has it just "gone wrong"?

 

More details and photo's of the system please?

[Temp]

+1 to more history needed.

 

Are there any flow meters on the manifolds and what do they say?

 

Does the boiler seem happy? Or is it switching on and off very frequently? 

[Tag]

Hi

The 4 zone heating system two radiator circuits and one hotwater.

The boiler is a vaillant 837.The underfloor is 120 Sq.

The ground floor is underfloor heating with 11 zones with 100mm celotax  70 mm screed with tiles.

The boiler tends to cycle on and off does not get up to temperature.

Each zone has a heatmiser actuator and a heatmiser thermostat.

 

Thanks

[ProDave]

The important question:

 

Is this an existing system that has previously worked but has stopped working properly?

 

Or is it new and it has never worked properly?

 

Important because at the moment we don't know if we are looking for a design fault or a part failure.

[Tag]

Hi Prodave

The system is new it's taking a long time to heat up even a single zone.

I have bled the system using main pressure but no luck.

The flow gets very hot but return is very slow.

 

Thank

[PeterW]

Would think the blending valve is at fault. 
 

Can you take some photos of the setup..?

[Tag]

Hi Peter

 

This is the manifold.

Thanks

[PeterW]

Thanks - have you tried altering the white temperature setting on the valve at the far end..??

 

Do the rails get hot..?

Do the actuators rise up on all zones..?
The top rail flow valves - do they move when the actuators start ..?

I’m assuming this was taken during maintenance as the isolators are closed and there is a gap in the pipework ...

 

[ProDave]

Is the pump on the manifold running, if there is no light on it you should be able to hear it humming / whirring.?

[Tag]

The top rail gets hot, the flow meters do rise but some of them do not.The pump is running on speed 3.

[PeterW]

Are all the actuators opening ..?? Sounds like some are not. 

[Temp]

The picture of the manifold appears to have been taken with all actuators closed and no flow in any loops. So when it was taken either the UFH was off or all the stats were  satisfied. Can you take a similar photo with all or several of the stats calling for heat? 

 

Edit: Actually it looks like the photo was taken during installation. One of the flow or return pipes isn't yet connected at the left hand side?

Edited April 13, 2021 by Temp

[Tag]

hi Guys 

thanks for the reply’s here is an update

took air out of the system individually fitted a pump on the return got  the system working after 5 hours from cold.The customer has range back to say not working again.

 

thanks