UFH added to exisiting Y Plan system - advice needed

[Madrab]

If the flow right up to the UFH Tee is => 60Deg then the blending valve isn't doing it job, if you can't get the mix temp up to 50deg'ish. How do you know the blended temp, is there a gauge on the manifold? Was it just left like this or has this just happened since the commissioning and hand over?

A pic of the manifold/setup would be good What are the flow valves set to?

 

[Madrab]

If the UFH has its own pump then don't worry too much about placement in relation to the system pump, it's just needs to be set up properly and the pumps accurately balanced.

 

[AMR1]

If the flow right up to the UFH Tee is => 60Deg then the blending valve isn't doing it job, if you can't get the mix temp up to 50deg'ish. How do you know the blended temp, is there a gauge on the manifold? Was it just left like this or has this just happened since the commissioning and hand over?

A pic of the manifold/setup would be good What are the flow valves set to?

This is the manifold, out of shot is the 2 port valve which is on the flow pipe just before the thermostatic mixing valve (sorry, IMG tags don't appear to be working!) -

ManifoldPumpMixer

• AMR1
• 23 Dec 2020

There is a temperature gauge on the manifold after the blending valve (top left) and pump, this never gets above 30c and typically sits at mid-20s regardless of the mixer valve setting. I've tried different mixer valve settings (1-6) and this has little to no impact on the temp reading. This has all happened since comissioning and hand over. Flow valves normally read around 2 l/min, but fluctuate between 1.5 and 2.5 when the system is running.

If the UFH has its own pump then don't worry too much about placement in relation to the system pump, it's just needs to be set up properly and the pumps accurately balanced.

AFAIK the pumps haven't been balanced, our main pump is a Grundfos UPS2 which has 3 constant speeds (currently set to 2) and the pump on the UFH is a Wilo Para which has constant speed, variable differential pressure, and constant differential pressure; along with three speed settings. This is currently set to constant speed setting on the 2nd speed.

 

[Madrab]

OK, I guess all you can do is measure the inlet temp - pipe into the bottom of the mixing valve and then confirm the output temp to the pump. I would use an IR thermometer.
I wouldn't necessarily worry about the pump interaction just now if you are getting sufficient flow across the meters, the temp is the important part here. If it is confirmed that the temp isn't getting about 20 odd degrees then there is an issue at the blending valve and that needs looked at. Who is the kit manufacturer?

Ultimately we can only remote check this, it really should be the installer that should be back sorting it out.

 

[AMR1]

OK, I guess all you can do is measure the inlet temp - pipe into the bottom of the mixing valve and then confirm the output temp to the pump. I would use an IR thermometer.
I wouldn't necessarily worry about the pump interaction just now if you are getting sufficient flow across the meters, the temp is the important part here. If it is confirmed that the temp isn't getting about 20 odd degrees then there is an issue at the blending valve and that needs looked at. Who is the kit manufacturer?

Ultimately we can only remote check this, it really should be the installer that should be back sorting it out.

Agree, and I am telling him he needs to come back and sort this out, I was looking for opinions on what the issue is so I don’t get fobbed off with excuses.

The kit is made by Essco using ESBE mixer and Wilo pump

 

[picasso]

Take the white caps off the manifold and can you post a pic of the pump running and the flow meters ?

 

[AMR1]

Take the white caps off the manifold and can you post a pic of the pump running and the flow meters ?

Sure

FlowMetres

• AMR1
• 23 Dec 2020

Pump

• AMR1
• 23 Dec 2020

I did try to get a temperature reading from the flow pipe coming in but was struggling with my IR thermometer due to emissivity of copper pipes! At one point it was close to 60c, but this varied over a 5 minute period between 25c and 60c (no changes were being made to the UFH system at this time)

 

[picasso]

Any idea how long the loops are under the floor ?

 

[AMR1]

Any idea how long the loops are under the floor ?

Roughly 50-60m each if I remember correctly

 

[picasso]

Then your flow rates are about right.

 

[AMR1]

Then your flow rates are about right.

At least 1 thing is! Flow rates should be around 2l/min from what I have read and been told?

Just the mixing valve and flow temperature problem to resolve now!

 

[AMR1]

Some further progress with diagnostics.

Flow pipe to the mixer reads within 1-2c of the flow pipe from the boiler, normally in the 62-64c range.
Pump is circulating in the UFH system, flow rates generally 1.5-2 L/min on the gauges

The mixer is numbered 1-6, according to the manual 1 = 20c, 6 = 55c.

If the mixer is set to between 1-4, temperatures for the UFH sit around 25-27c, if I set it between 4-6, temperatures sit around 33-35c. What's strange is the time it takes to adjust, if I set it to 2 and let temperatures stablise around 25c, then adjust it to 6, it takes 30-40 minutes for the temperatures to rise in the system.

Am I right in assuming the issue here is with the mixer not mixing correctly as all other variables seem to be correct?