Balancing UFH

[snb]

Just check the following, some you may have already done but might be worth revisiting.
Flow and return valves fully open
All flow valves fully open
Pump set on max speed
Blending temp set at

You should see/get Flow return differentials of 7 degrees once the system
Has been running for about 6 hours if you have the thermostats demanding for heat.

If this doesn’t happen then it would suggest that either the floor sensor is positioned too close to flow pipe or faulty floor stat ( if this is causing that particular zone to be turned off or the floor is above 27)

Biggest problem we get with a mix of floor coverings is the heat output. Having too high an output on some floor coverings can cause those rooms to be much warmer and the air mixing through to other rooms creates a warm enough temp at 1.3m high ( but switches that zone off) creating the room to be too cold at seating height.

 

[chriselevate]

Just check the following, some you may have already done but might be worth revisiting.
Flow and return valves fully open
All flow valves fully open
Pump set on max speed
Blending temp set at

You should see/get Flow return differentials of 7 degrees once the system
Has been running for about 6 hours if you have the thermostats demanding for heat.

If this doesn’t happen then it would suggest that either the floor sensor is positioned too close to flow pipe or faulty floor stat ( if this is causing that particular zone to be turned off or the floor is above 27)

Biggest problem we get with a mix of floor coverings is the heat output. Having too high an output on some floor coverings can cause those rooms to be much warmer and the air mixing through to other rooms creates a warm enough temp at 1.3m high ( but switches that zone off) creating the room to be too cold at seating height.

Flow and return ball valves fully open
Flow and returns on the manifold not fully open - would you open them fully and let the acutuators control the rest?
Pump on max speed
Boiler flow set to 65
Blending temp set to 40
Return coming back at 30

Sometimes the flow/return differential narrows to 7c but it’s not very often. It’s mainly 10c different.

Would you strongly advise not setting the floor probe to cut off any higher or will 3c or similar be ok? It is the bottom surface that they are referring to as 27c as opposed to the top surface etc?

Thanks for all the help on this. It’s frustrating that it’s cost all this money and it’s winter and we’re cold in the house. Any help and suggestions are really appreciated.

 

[snb]

Because the differential is above 7 at times it is not giving the maximum output.

Open all flow valves to max and only reduce the ones if the flow rate is greater than 3. This will help the system self balance much quicker and put more flow into the loops that need it.
No don’t increase floor limit temperature.
If you are certain the floor limit probe is switching the system off then reduce the flow temp by 2 degrees to see if it allows it to stay on. Personally 40 flow temp could be too high as I normally install with 30 to 35 flow and then increase upwards of the output isn’t enough

 

[chriselevate]

Cool, thanks. So the mixer valve is closed as tight as possible and gives me 40c. Would you suggest taking the boiler down in temperature as it’s current set to 65c?

When the flow is mixed to 40c the floor probe didn’t hit 27c. If I turn the mix up slightly the probe limit does kick in. So I think it’s around that temperature that it cuts out.

 

[snb]

Hopefully then getting the flow rates increased through some loops so the differential is closer to 7 may give you the extra you need.

The blending valve can be altered lower. You have to undo the plastic head using the Allen key and move it around. But only bother if you need to.

Increasing the floor limit by a degree or 2 shouldn’t cause any problems with the floor but you do it at your own risk.

Just checking but you are making sure that all doors upstairs are kept closed. This will increase ground floor temps

 

[chriselevate]

You agree that the 65c is a good output temperature from the boiler? You’d also leave it at 40c for the mixed temperature seeing as it’s not activating the floor probe at 27c?

I have a horrible feeling that when I only run it with the one stat calling for heat it still doesn’t have a difference of 7c but I’ll try it again with the flow guages fully out.

Doors being shut upstairs is something we always do. Interesting point.

 

[chriselevate]

Ok, one interesting thing that I’ve noticed. I’ve opened up all the flow valves and when just one thermostat (two loops/valves) is calling for heat, it only achieves a 2 flow rate and not the 3 like you mentioned. This is with the wilo pump on full (6). Photo attached.

I’ve increased the mixed flow to 52c and the return temperature is coming back at 42c after several hours of running. Your suggestions and ideas are really appreciated.

 

[Madrab]

You are ultimately throttled by the wooden flooring, as it has a max limit. If you are reliably attaining a floor temp of 27Deg and the room isn't warm enough then the Kw/m2 needs to increase. Only a rise in the floor temp can supply that.

So you need to decide if the wooden floor can take the extra heat req or it's lift the wood and get something with a low R-(tog)value installed and up the floor temp.

 

[chriselevate]

Thanks, yes I agree. Lifting the expensive floor isn’t going to happen due to budget. It’s only just been fitted and it’s the flooring we want. I’ve raised the floor probe cut off and it’s better tonight but I’m still interested why the flow doesn’t go higher than 2 (even just running two loops with the pump on full) and the differential temperature consistently being 10c and never much lower.

I’m hoping this can be solved somehow.

 

[Jay88]

Firstly make sure you have definitely got all the air out of the loops, this makes a massive difference on flow, do this by shutting main flow and return valves, shut all flow gauges and loosen actuators off so all zones are effectively open. Attach mains pressure hose to the drain cock on the flow bar (top) and another hose to the return drain on the return bar (bottom) to a grid or drain,turn water on and one zone at a time open flow gauge fully until a good constant flow of water is achieved! Then shut and repeat on all zones.

Then with the wilo pump you have two different settings, not sure which way around but on the control knob one way is recommend for a rad circuit and the other way for an underfloor circuit, see instruction booklet.

Also make sure that you restrict your short zones slightly using the flow gauge and your longer zones try to achieve 2/3 lpm

I had similar problems with a wunda manifold with the wilo pump! Personally i dont think the pump is up to the job, i only fitted as on a new build site and that was what was provided! I usually stick to john guest because i think there a much better set up, but anyway every other wunda manifold I commissioned had a grundfos 25-40/60 and all worked perfectly so wether they know the pump not up to the job and now supply grundfos im not sure but thats what i would be looking at.

 

[snb]

Open the auto air vent on the upper underfloor manifold and then in one loop at a time remove the actuator head on each loop and run for 15mins. You should get least 4lt/min but even on a max 120m loop you should still get over 3lt/min with one just loop open. Hopefully it’s just a bit of air causing the poor flow rate. Otherwise it has partially crushed pipe.

 

[Jay88]

Pretty sure no AAV on these manifolds manual bleed only, as i said thats the quickest way to get rid of air on any manifold, they are dog ****

 

[chriselevate]

Firstly make sure you have definitely got all the air out of the loops, this makes a massive difference on flow, do this by shutting main flow and return valves, shut all flow gauges and loosen actuators off so all zones are effectively open. Attach mains pressure hose to the drain cock on the flow bar (top) and another hose to the return drain on the return bar (bottom) to a grid or drain,turn water on and one zone at a time open flow gauge fully until a good constant flow of water is achieved! Then shut and repeat on all zones.

Then with the wilo pump you have two different settings, not sure which way around but on the control knob one way is recommend for a rad circuit and the other way for an underfloor circuit, see instruction booklet.

Also make sure that you restrict your short zones slightly using the flow gauge and your longer zones try to achieve 2/3 lpm

I had similar problems with a wunda manifold with the wilo pump! Personally i dont think the pump is up to the job, i only fitted as on a new build site and that was what was provided! I usually stick to john guest because i think there a much better set up, but anyway every other wunda manifold I commissioned had a grundfos 25-40/60 and all worked perfectly so wether they know the pump not up to the job and now supply grundfos im not sure but thats what i would be looking at.

Thanks, really helpful and good advice. I’m pretty sure all air is out because the system is running lonely a quiet now and I can’t hear any air noise. When I first setup the system there was a fair amount of air noise so I stopped and started from scratch by purging the air out of every loop. It worked well and I got lovely water running into my bucket for each loop.

I am a big fan of gundfoss and my original purchase was for a grundfoss but the manifold cabinet I added to the order (waterproof cabinet) they said isn’t big enough to fit one so then changed it to a wilo pump and said they are just as good.

The pump has “variable” and “constant” settings (like you said). Wunda told me to set to constant 3 (it goes 1, 3 and 6). I have increased to 6 to get flow rates better and this helped to achieve 2 lpm but never any higher.

I’ll try purging again but I’m sure it’s not got any air in but it’s worth a try.

 

[chriselevate]

Open the auto air vent on the upper underfloor manifold and then in one loop at a time remove the actuator head on each loop and run for 15mins. You should get least 4lt/min but even on a max 120m loop you should still get over 3lt/min with one just loop open. Hopefully it’s just a bit of air causing the poor flow rate. Otherwise it has partially crushed pipe.

As Jay said, there’s no auto air vent that I can see or know of I’m afraid.

I don’t get anywhere near 4lpm on any of the loops even when just one loop is open and calling for heat.

 

[Jay88]

Firstly make sure you have definitely got all the air out of the loops, this makes a massive difference on flow, do this by shutting main flow and return valves, shut all flow gauges and loosen actuators off so all zones are effectively open. Attach mains pressure hose to the drain cock on the flow bar (top) and another hose to the return drain on the return bar (bottom) to a grid or drain,turn water on and one zone at a time open flow gauge fully until a good constant flow of water is achieved! Then shut and repeat on all zones.

Then with the wilo pump you have two different settings, not sure which way around but on the control knob one way is recommend for a rad circuit and the other way for an underfloor circuit, see instruction booklet.

Also make sure that you restrict your short zones slightly using the flow gauge and your longer zones try to achieve 2/3 lpm

I had similar problems with a wunda manifold with the wilo pump! Personally i dont think the pump is up to the job, i only fitted as on a new build site and that was what was provided! I usually stick to john guest because i think there a much better set up, but anyway every other wunda manifold I commissioned had a grundfos 25-40/60 and all worked perfectly so wether they know the pump not up to the job and now supply grundfos im not sure but thats what i would be looking at.

Thanks, really helpful and good advice. I’m pretty sure all air is out because the system is running lonely a quiet now and I can’t hear any air noise. When I first setup the system there was a fair amount of air noise so I stopped and started from scratch by purging the air out of every loop. It worked well and I got lovely water running into my bucket for each loop.

I am a big fan of gundfoss and my original purchase was for a grundfoss but the manifold cabinet I added to the order (waterproof cabinet) they said isn’t big enough to fit one so then changed it to a wilo pump and said they are just as good.

The pump has “variable” and “constant” settings (like you said). Wunda told me to set to constant 3 (it goes 1, 3 and 6). I have increased to 6 to get flow rates better and this helped to achieve 2 lpm but never any higher.

I’ll try purging again but I’m sure it’s not got any air in but it’s worth a try.

Is that the cabinet in the picture? If so then i would of thort a grundfos would fit there! As i say never had any problems with the grundys and it is a bigger bore pump which i would of thort should sort your problem, ive used them on 5-6 bedroom houses with about 12 zones and once air is out the system away they go, as you say though if its running quiet then chances are you wont have air in the system! Never been a big fan of wilo pumps, may not be the problem but thats what my money is on