ASHP heating parameters for UFH

[Happy Valley]

We have a well insulated house ICF walls - 200mm concrete raft with 200mm insulation and 70mm screed. Triple glazed apart from the sliders.

 

The installer is suggesting we run the UFH at 45 degrees with a lower level of 35 degrees. Temp requirement will be 21 degrees

 

What range of temps do you run yours at?

[Stones]

You'll have massive overshoot of internal temperatures at 45C flow temp.

 

We are in an ICF build, and flow temps generally run between 30 and 35C. We also have a Mitsubishi Ecodan 8.5 kW with FTC5 controller, set at 21C target temp through winter.

 

Personally, I'd use the auto function and target temperature on the controller and let it sort itself out.

[Happy Valley]

Thanks - I thought the temps were high having read a few threads on here. Shall ask them to reduce the max and min flow temps.

[JohnMo]

This will tell you your mean flow temp.  Mean flow temp half your delta T between flow and return taken away from the flow temp.

 

House total loss divided by UFH area. To get W/m2. Get your pipe spacing a draw a line, as illustrated.

[JohnMo]

Forgot to mention once set you may have to adjust to compensate for the floor covering.  That should be the flow for the lowest out side air temp

[PhilT]

5 hours ago, Stones said:

You'll have massive overshoot of internal temperatures at 45C flow temp.

We are in an ICF build, and flow temps generally run between 30 and 35C. We also have a Mitsubishi Ecodan 8.5 kW with FTC5 controller, set at 21C target temp through winter.

Personally, I'd use the auto function and target temperature on the controller and let it sort itself out.

I recently looked into this myself for my Ecodan with conventional radiator circuit. Mitsubishi tech help told me:- "Auto adaption can only be used with Mitsubishi thermostats. UFH is generally used with third party thermostats so you will need to select the heating mode to fixed flow or weather compensation."

[Stones]

I run my house as a single zone, using the FTC controller as the thermostat. The bedroom.have there own but they only open and close the individual loops in the UFH, they do not call on the ASHP for heat.