UFH Upstairs temperature help

[richo106]

1 hour ago, Nickfromwales said:

Defo needs a FLIR / IR thermometer so you can see the heat pushing through the pipes (or not). 
 

Sorry, that doesn’t answer my question. The loops need to be purged one by one with cold mains. If this didn’t happen then it needs to, if you’re looking to eliminate every possible reason why this isn’t working properly.

 

My immediate gut feeling is that you should defo have had 2x manifolds, each with their own pumps, and each with a TMV; this would allow a higher flow temp to the FF UFH and for the GF to be dialled back accordingly. 
 

You have 2 very different emitters here, BUT, if well insulated/airtight/MVHR then the requisite heat for the FF should be minimal.

 

I’m glad, as the install in the pic is 🐕 💩. 

I apologies for these daft questions but i can borrow an IR gun from work, what areas should be checking with this? Just floor temps? Or the pipes also?

 

I am going to ask the plumber if he did this, how can i do this now just to ensure there is no air lock? Is it possible to do?

 

I have 2 x manifolds but one common pump, would turning GF off prove that another pump may help or not?

 

Can't seem to get it above 20 deg with cold floors though, tiles feel very cold. Once i shut the doors the temp decreases through the night. I am guessing this doesn't help that i turn my heating off 4 - 7 due to high energy costs

 

 

 

 

 

[richo106]

Update (1)

 

My heating come back on at 7pm (is this cost effective do you think switching it off for the 3 hours?)

7.30pm All FF manifolds flow rate approx 2 on all of them, 25 deg in and 24 out

7.30pm I turned down all GF thermostats so no call for heating. ASHP still running and pump running

7.35pm the flow indicators on my GF were still showing flow even though all call for heat was off, i turned off isolation valve on manifold. All flow rate indicators shot up to show no flow

FF manifold flows rates immediately shot up all to around 3 and a couple closer to 4

8pm - flow rates still the higher values - 25 deg in and 24 deg out

 

How long would you leave it like this to see if it actually makes a difference? Would this increased flow make a difference?

 

I have attached a picture of my pump set up, green arrow is to GF manifold approx 4m of pipe and red arrow is FF manifold approx 9m of pipe

[richo106]

Any advice what to try next would be great or what to look out for.

 

If i installed another pump would this improve flow rates on both manifolds? could i even do this? (apologies terrible plumbing knowledge!)

 

Another idea is that i know i turn the heating off between 4 -7 (cosy tariff and expensive period!) could i leave FF running?

 

Sorry all the questions just very determined to hopefully get to the bottom of it one way or another

  

[Nickfromwales]

1 hour ago, richo106 said:

Any advice what to try next would be great or what to look out for.

 

If i installed another pump would this improve flow rates on both manifolds? could i even do this? (apologies terrible plumbing knowledge!)

 

Another idea is that i know i turn the heating off between 4 -7 (cosy tariff and expensive period!) could i leave FF running?

 

Sorry all the questions just very determined to hopefully get to the bottom of it one way or another

  

Now sat in the Doghouse in Manchester, and determined to get to the bottom of a nice cold pint of Wingman, aka “Mother’s milk”. Been a long day so may have another…. 😋 

 

First question, should have asked sooner, but what was the flow and return temps of the FF UFH before any (possible) heat hit it?

 

Exactly the results I expected, so thanks for the feedback. Pump potential, when made divisible, is simply insufficient. GF UFH steals the lions share, ‘path of least resistance’, so the FF gets the scraps; issue here is, the FF UFH needs a lot more attention.

 

This needs some surgery methinks.

 

Firstly, as suggested previously, you can mess about with flow rates, however I think this will get you nowhere (sorry) and a few changes need to happen.

 

Before surgery, the consultant in me needs to be pragmatic. That said, let’s see what we can gather before booking you in for the full, frontal lobotomy .

 

First off, the differential of the FF flow and return are garbage, which suggests there’s a lot of airlocks occurring. 1°C suggests zero flow, tbf.

 

Is there an automatic air vent on the FF UFH manifold? Pic plz if so (and does it work / is the cap open 2 turns?).

[richo106]

16 minutes ago, Nickfromwales said:

Now sat in the Doghouse in Manchester, and determined to get to the bottom of a nice cold pint of Wingman, aka “Mother’s milk”. Been a long day so may have another…. 😋 

 

First question, should have asked sooner, but what was the flow and return temps of the FF UFH before any (possible) heat hit it?

 

Exactly the results I expected, so thanks for the feedback. Pump potential, when made divisible, is simply insufficient. GF UFH steals the lions share, ‘path of least resistance’, so the FF gets the scraps; issue here is, the FF UFH needs a lot more attention.

 

This needs some surgery methinks.

 

Firstly, as suggested previously, you can mess about with flow rates, however I think this will get you nowhere (sorry) and a few changes need to happen.

 

Before surgery, the consultant in me needs to be pragmatic. That said, let’s see what we can gather before booking you in for the full, frontal lobotomy .

 

First off, the differential of the FF flow and return are garbage, which suggests there’s a lot of airlocks occurring. 1°C suggests zero flow, tbf.

 

Is there an automatic air vent on the FF UFH manifold? Pic plz if so (and does it work / is the cap open 2 turns?).

I am not sure regarding the flow/return temps before any heat hit it sorry

 

I have just check the flow temps again and no change just the 1 deg diff

 

Please find attached pic of the air vent, to be honest i have to google to see what you meant by that! I have not touched it so any advice what to try I am all ears  

[Nickfromwales]

2 minutes ago, richo106 said:

I am not sure regarding the flow/return temps before any heat hit it sorry

 

I have just check the flow temps again and no change just the 1 deg diff

 

Please find attached pic of the air vent, to be honest i have to google to see what you meant by that! I have not touched it so any advice what to try I am all ears  

 

Those caps are like the ones on your car tires. They need to be ‘loose’ to work, so give them a ‘twiddle’ and see what the situation is there plz. 
 

Close them finger tight, and then open 2 full turns 720°, if unsure. Then they’ll be able to function properly and let ‘air’ out. 

[richo106]

9 minutes ago, Nickfromwales said:

 

Those caps are like the ones on your car tires. They need to be ‘loose’ to work, so give them a ‘twiddle’ and see what the situation is there plz. 
 

Close them finger tight, and then open 2 full turns 720°, if unsure. Then they’ll be able to function properly and let ‘air’ out. 

They were both quite tight 

 

I have done that, tightened them and then I have backed them off 720 deg

Edited October 27 by richo106

[Nickfromwales]

4 minutes ago, richo106 said:

They were both quite tight 

 

I have done that, tightened them and then I have backed them off 720 deg

If they were tight, then they weren’t doing any venting.

 

 A box has been ticked. ✅ 

[richo106]

4 minutes ago, Nickfromwales said:

If they were tight, then they weren’t doing any venting.

 

 A box has been ticked. ✅ 

Are these ok to leave ‘open’ then I am guessing. Do I need to manually purge each loop or if I have air locks will the auto air vents clear it all over a period of time? 

[Nickfromwales]

1 minute ago, richo106 said:

Are these ok to leave ‘open’ then I am guessing. Do I need to manually purge each loop or if I have air locks will the auto air vents clear it all over a period of time? 

These should have been left open by the installer. They stay ‘open for life’ so they can look after you and let any ‘air’ out. 

[richo106]

Ok that’s great thank you, guessing this isn’t going to fix all my issues though 😂😂

[Nickfromwales]

20 minutes ago, richo106 said:

Ok that’s great thank you, guessing this isn’t going to fix all my issues though 😂😂

Step 1   

[richo106]

I thought i would unscrew all the actuators to see if that would make a difference (not expecting it to)

6.55pm - temp in and out was 21deg (heating been off 3 hours)

7.01pm - temp in was 25 and temp out 21 - also changed over temp gauge to prove working

7.05pm - 23 deg in and out

8pm - 25 deg in and out. For ref the GF manifold temp in 25 deg and and temp out 22 deg

 

Saturday I am going to refill all FF loops just to ensure there is no air in there, once again i am not expecting this to make much difference as there is visible flow on the flow meters (which changes when GF manifold off) but just ticks another thing off 

 

[richo106]

21 hours ago, Nickfromwales said:

Step 1   

@Nickfromwales I would love to know what step 2 is  

[Nickfromwales]

3 minutes ago, richo106 said:

@Nickfromwales I would love to know what step 2 is  

FLIR camera to see if waters making its way around the FF loops most prob. 
 

Or feck off to the pub, and order a jumper on Prime whilst supping soothing cold beer.

[richo106]

Update

 

I have borrowed an IR camera to check flow and return temps of the FF manifold 

 

The heating turned on at 7pm

I have recorded the temps at 7.15pm and 7.45pm, please see attached picture to show my findings

There is definitely heat loss but not much 

 

I have also IR camera'd the carpeted floor and can see the heat lines, this was around 8pm and the temp of the heat was around 20.2 deg and the 'cold bit' was 19.6 deg 

 

There was no of any heat lines on the tiled floor in the bathrooms yet (there is downstairs but appreciate the floor make up is different)

 

For this shows the water is getting round the loops at least

 

One thought i have now is to take it off weather compensation curve and set the water temp to 35 deg, this will make the GF 'bounce off' the thermostats though. I am not sure this will make enough difference on the freezing cold days upstairs though

 

Any other thoughts/ideas on my findings today would be grateful, many thanks

[richo106]

At 9pm I upped my water temp to 35 deg

 

At 11pm I checked the flow and return temps on my FF manifold, average in was 32deg and return 31deg. So averaging around 1 deg heat loss

 

My bathroom tiled floor has increased from 20.5deg to 21 deg from 7pm to 11pm

 

I am not sure where to go next

[John Carroll]

To calculate any UFH output, kW = (total loops flowrate (LPM) X 60 X UFH (flowtemp-returntemp))/860. For example a UFH manifold with a total Flowrate of 15LPM with flowtemp-return dT of 1C will have a output of (15*60*1)/860, 1.05kW.

[JohnMo]

Sounds like the heat is circulating, but not being absorbed very well. So not being transferred to the floor.

 

I had a similar issue with an overlay system in theory should have performed great in practice was pretty similar to what you are seeing. Low dT and very poor output, for a given flow temperature.

[richo106]

5 hours ago, John Carroll said:

To calculate any UFH output, kW = (total loops flowrate (LPM) X 60 X UFH (flowtemp-returntemp))/860. For example a UFH manifold with a total Flowrate of 15LPM with flowtemp-return dT of 1C will have an output of (15*60*1)/860, 1.05kW.

Thanks @John Carroll

Currently the 11 loops on the manifold have an average flow rate of approx of 2l/m so would that mean total flow rate of approx 22LPM.

 

Is there anything that can be done to increase the  dT at all? Guessing that’s to do with install etc 

 

Is it as ‘simple’ as splitting the GF and FF circuits and have a pump for each? If the new/separate pump increases flow rate to approx 3 for example. Or would it be better to aim for 4? When I turned the GF Monifold off previously the flow rates did increase to around 3 but even we some tweaking on the flow rate indicators I couldn’t get them To increase passed that 

[richo106]

5 minutes ago, JohnMo said:

Sounds like the heat is circulating, but not being absorbed very well. So not being transferred to the floor.

 

I had a similar issue with an overlay system in theory should have performed great in practice was pretty similar to what you are seeing. Low dT and very poor output, for a given flow temperature.

Did you manage to anything to improve it? Or just manage with it? 

[JohnMo]

No gave up in the end and bypassed it, mine was in a summer house, installed a fan coil instead.

 

Without a screed or biscuit mix to get good around contact with the pipes, UFH is pretty pants from my experience. The other way around it, is to throw huge temperatures at it - but that's not in my comfort zone.

[John Carroll]

1 hour ago, richo106 said:

Thanks @John Carroll

Currently the 11 loops on the manifold have an average flow rate of approx of 2l/m so would that mean total flow rate of approx 22LPM.

 

Is there anything that can be done to increase the  dT at all? Guessing that’s to do with install etc 

 

Is it as ‘simple’ as splitting the GF and FF circuits and have a pump for each? If the new/separate pump increases flow rate to approx 3 for example. Or would it be better to aim for 4? When I turned the GF Monifold off previously the flow rates did increase to around 3 but even we some tweaking on the flow rate indicators I couldn’t get them To increase passed that 

 

22LPM at a dT of 1C gives a UFH output of, 22*60*1/860, 1.54kW, pretty hopeless for a 11 loop system. Normally one might expect a dT of at least 4C/5C at a flow rate of 2.5LPM/loop even with a low flow temperature, this then gives, 2.5*60*(say) 4.5/860, 0.785kW per loop, in your case, ~ 8.6kW. Increasing the flow rate decreases the dT but should result in a greater output, but something definitely wrong when you are only getting a dT of only 1C.

 

You also posted that when you shut down the GF that the FF flowrates almost doubled with the same dT, this, theoretically doubles the UFH output, can you post the total flow through the GF, can then look at the pump curve, if available, for that 8M ST pump, you might be able to get a suitable circ pump to give you 3.5/4.0LPM. 

How is the ASHP supplying the UFH, has it got its own pump?

[richo106]

7 hours ago, John Carroll said:

 

22LPM at a dT of 1C gives a UFH output of, 22*60*1/860, 1.54kW, pretty hopeless for a 11 loop system. Normally one might expect a dT of at least 4C/5C at a flow rate of 2.5LPM/loop even with a low flow temperature, this then gives, 2.5*60*(say) 4.5/860, 0.785kW per loop, in your case, ~ 8.6kW. Increasing the flow rate decreases the dT but should result in a greater output, but something definitely wrong when you are only getting a dT of only 1C.

 

You also posted that when you shut down the GF that the FF flowrates almost doubled with the same dT, this, theoretically doubles the UFH output, can you post the total flow through the GF, can then look at the pump curve, if available, for that 8M ST pump, you might be able to get a suitable circ pump to give you 3.5/4.0LPM. 

How is the ASHP supplying the UFH, has it got its own pump?

Yes I can understand the low dT, I checked the temps again this morning and loops ranged between 1-1.8 deg loss, but IR camera was bouncing around a little so hard to be super accurate 

 

I will turn off the GF manifold again so the the pump just feeds the FF to see what flow rates I can achieve per loop.

 

currently the ASHP feeds a buffer tank and then pumped from there to both manifolds using a single pump.

 

one thing that I want to try is not shutting my heating off during 4-7 during the expensive period to see if this makes any difference at all. I’ll just run my heating 24/7 on weather comp with thermostats set at 23.5 to stop overheating. 
do you think this will make much difference cost wise? It takes a large amount of energy to reheat the floors and buffer tank when it heats back up at 7 so hopefully it won’t be too much difference

 

any thoughts on this would be helpful  

[marshian]

25 minutes ago, richo106 said:

one thing that I want to try is not shutting my heating off during 4-7 during the expensive period to see if this makes any difference at all. I’ll just run my heating 24/7 on weather comp with thermostats set at 23.5 to stop overheating. 
do you think this will make much difference cost wise? It takes a large amount of energy to reheat the floors and buffer tank when it heats back up at 7 so hopefully it won’t be too much difference

 

any thoughts on this would be helpful  

I know that on my house set up (all rads) setback temps (2 deg setback) just don’t save me any energy - the reheat from setback uses more energy than maintaining a stable temp 24/7 

 

perhaps if I used either a smaller setback or a larger setback it might be different but if I used larger setback I might as well just go back to a schedule and a smaller one seems pointless