UFH Upstairs temperature help

[John Carroll]

41 minutes ago, richo106 said:

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 probably answered your query re continuous heating.

 

You might check the Stuart Turner circ pump mode&setting, it has three constant curve settings and three proportional pressure settings, ensure its on constant curve setting 3, if not sure of the modes, tahe a photo of the pump switch or LEDs while running.

 

[richo106]

26 minutes ago, John Carroll said:

 

@marshian probably answered your query re continuous heating.

 

You might check the Stuart Turner circ pump mode&setting, it has three constant curve settings and three proportional pressure settings, ensure its on constant curve setting 3, if not sure of the modes, tahe a photo of the pump switch or LEDs while running.

 

Yes I will certainly try 24/7 running, will set this up tonight to see how I go on for the next few days. Will try and monitor temp and energy consumption best I can but not too cold at the minute 

 

If this doesn’t make anything difference I’ll defo look at increasing the flow rate, somehow splitting the circuits and installing an additional pump 

[marshian]

31 minutes ago, John Carroll said:

 

@marshian probably answered your query re continuous heating.

 

 

Every house I appreciate is different and responds accordingly but I was running 2 deg setback in most of the rooms for 4 hours at night and 5 hours in the day and in a week of relatively stable OAT's I used more energy on the setback days than I did on the 24/7 (if anything the setback days were slightly warmer although I was only looking at the average temp between coldest and warmest temp across 24 hrs (it could have been colder for longer on the warmer days)

 

It's one of those experiments that you do for fun

[richo106]

[marshian]

1 minute ago, richo106 said:

Yes I will certainly try 24/7 running, will set this up tonight to see how I go on for the next few days. Will try and monitor temp and energy consumption best I can but not too cold at the minute 

 

If this doesn’t make anything difference I’ll defo look at increasing the flow rate, somehow splitting the circuits and installing an additional pump 

 

You might not need to split the circuits - Heat Geek did a video on pump distortion not that long ago

 

 

[richo106]

I just turned my GF manifold off and checked the flow rates of the FF one

 

Basically when the downstairs is on its looking approx 24/25 

When the downstairs is off its about 35

 

Is that what people would expect?

 

I will look into the pump settings shorty

[richo106]

[richo106]

Right after looking on the internet

My pump was on proportional power - medium (flashing green)

I have now changed this to constant power - highest power (constant orange)

 

 

[marshian]

1 minute ago, richo106 said:

Right after looking on the internet

My pump was on proportional power - medium (flashing green)

I have now changed this to constant power - highest power (constant orange)

 

Modern pumps are a real head fug - they are a bit to damn clever sometimes

 

My limited understanding is the faster the pump speed the smaller the delta between flow and return so you give the emitter more time to get rid of the heat (That's the impact in my house) but in your case where you are trying to get the emitter to give off more heat it may well prove effective - guess testing and monitoring are required

 

Having said that constant curve is what I settled on (mainly because the flow on proportional settings changed from when I first set the pump up to maybe a week or so later - some learning logic I think)

[marshian]

19 minutes ago, richo106 said:

I just turned my GF manifold off and checked the flow rates of the FF one

 

Basically when the downstairs is on its looking approx 24/25 

When the downstairs is off its about 35

 

Is that what people would expect?

 

I will look into the pump settings shorty

 

Blimey 34.5 litres a min is 2070 litres per hour.... that feels like a heck of a lot of flow.

[John Carroll]

Changing the pump mode should result in  increased flow, interesting to see if it actually does.

[richo106]

Hi All

 

We are now having the first cold snap since starting this thread. And unfortunately my daughter’s bedroom with door shut is Currently 17.5 degrees! 
 

The only thing I have changed so far from last year is not stopped the heating during the expensive period (16.00 - 19.00)

 

I think it’s pretty it’s the installation/lack of pipes that’s the main reason but I now just trying to thinks of ways to help it a little

 

I might change my weather comp to 35 deg at 0 deg (currently -3 or -5 can’t remember exactly )

I will turn my pump to powerful mode to increase l/min on the manifolds

is it worth increasing the temperature passed 35 deg or would then it become inefficient?

 

any other ideals would be very grateful 

[marshian]

23 minutes ago, richo106 said:

is it worth increasing the temperature passed 35 deg or would then it become inefficient?

 

any other ideals would be very grateful 

 

Being "super efficient but cold" or being "slightly less efficient and warm"?

 

Me I'll take the cooler option but Mrs Alien would rapidly be Mrs Ex-Alien (Divorces are a lot more expensive than energy) so I compromise and take the slightly less efficient option

[Nick Laslett]

@richo106, I have not been following this thread, but I feel your pain now that the cold winter weather has arrived. 
 

I’m not familiar with this approach or the design trade offs. I have no special knowledge about UFH installs. Just another amateur forum member. 
 

This blog advocates against using aluminium spreader plates with ASHP. They say it will need flow temp as high as 55°C, not 35°C. 

 

 

https://underfloorheating1.co.uk/blog/article/Water_Underfloor_Heating_and_Aluminium_Spreader_Plates?srsltid=AfmBOoositKuZ1fOjlxZgV8ygJwVgrd35zIhyDGKj6mPuA0uxoPp7vSo

The approach they advocate, might be a possible retro fit. But still a lot of work. 

 

https://underfloorheating1.co.uk/blog/article/Can_I_have_underfloor_heating_with_joisted_floors?srsltid=AfmBOopQsQvvgP2zHQn6UMCldTzV5P6j8MawfYv3Le-SGh1CHtie8wYo

 

 

Edited November 21 by Nick Laslett

[JohnMo]

As you have thermostats and a buffer

 

For now just go a fixed flow temp to see what temp you need to get FF output correct, start at 35. If your downstairs thermostat(s) switch of the HP, set all but one to the temp you want, leave one calling for heat (maybe turn down the flow to that loop).

[richo106]

I have been having a play with heating over the last week or so, instead of just changing my water temp to 35 deg I changed my weather comp curve so at 5 deg it was 35 deg. This just caused my downstairs to over heat really, when it warmed up it went too hot and then cooled down again rather than a nice constant temp

 

I didn't see much improvement in FF either, only left it for 24 hours due to being too warm downstairs

 

I have been doing some more reading and think i have come to the conclusion that the water temp needs to be at 45 deg to actually produce enough heat output on the plates. For info i have a 12kW Panosonic Aquarea monobloc 

 

Its frustrating as the weather comp how i have it set now works perfectly for downstairs (even the mrs is happy!) but upstairs heating is non existent.

 

I have a common 100L buffer tank and common pump for both GF & FF UFH, one (maybe daft) idea i have is to set my weather comp to 45 deg (not sure what other numbers yet haha) and then install a seperate cold water blending valve and pump to GF manifold - would this work you think?

 

I am complete novice when it comes to this so please any ideas/info would be very grateful!

 

In an ideal world i need my FF temp 45 and GF working off the weather comp like it is now  not sure that is possible though

 

COP data:

Heating (A7/W35): 12.00 kW | COP: 4.80
Heating (A7/W55): 12.00 kW | COP: 3.05
Heating (A–7/W35): 12.00 kW | COP: 2.82
Heating (A–7/W55): 12.00 kW | COP: 2.00

 

Kind Regards

 

 

[JohnMo]

I came to similar conclusion with our summer house. It runs off the same heating system as the house (UFH). I dumped the UFH in the summer house in the end, and used a fan coil radiator instead.

 

To me you need two different flow temps one for upstairs and a lower one for downstairs.

 

To achieve this you need a mixer downstairs.

 

Two ways to do this

An electronic mixer and treat the system upstairs as you would radiators. Your ASHP should be able to control the mixer - you would need to double check.

 

Or you add a mechanical mixer and pump to downstairs UFH and run a fixed flow temperature. Running WC upstairs should give a degree of temperature modulation. If you go this route go for an IVAR mixer set.

 

Like this - the option with the BritTherm is a good option, I used that same pump for a couple of years no issue, nice quite and pulls low watts.

https://www.heatingcontrolsonline.co.uk/ivar-thermostatic-mixing-valve-pump-set-p-1073.html

 

Or

 

https://www.outsourcedenergy.co.uk/product/manifold-mixer-station-wpb/

 

You want the one that adjusts from 20 to 60

[richo106]

Hi @JohnMo

 

Thanks very much for your reply and the solution regarding a separate manifold pump with blending valve makes sense to me. So just my benefit/understanding the only option is the to set the temperature of the blending valve so GF would have to run off fixed temp? 

 

If the temp was lower than the temp set on the blending valve i am guessing this would just not add any cold etc. so i could use the blending valve as a limiter?

 

As i would heating my water to upto 45 deg and then effectively cooling half of it on purpose would this cost a lot more to run?

 

Its frustrating as the higher temp is only needed when its probably colder than 5 deg outside so this is why I still need some sort of WC control

 

 

 

 

 

 

[JohnMo]

10 hours ago, richo106 said:

the temp was lower than the temp set on the blending valve i am guessing this would just not add any cold etc. so i could use the blending valve as a limiter

UFH mixing valve generally always have a percentage of mixing going on. So would act as limiter. You will get a variable flow temp but maybe not linear as the WC curve would suggest.

 

10 hours ago, richo106 said:

As i would heating my water to upto 45 deg and then effectively cooling half of it on purpose would this cost a lot more to run

The energy going to house wouldn't change, but as you are producing hotter water from heat pump cop would reduces, so would cost more.

 

Options I can think of (try 4 first zero cost option)

1. Electric radiators in problem rooms? With built-in timer and thermostat.

2. Add actuators to manifold downstairs, sort curve to suit upstairs, operate downstairs on a close hysterisis thermostat (0.1 to 0.2). No mixer just use thermostat to either open or closed all actuators on ground floor.

3. Simple mixer on ground floor operated similar to 2.

4. Not sure if you have tried this - reduced flows to downstairs loops to very low flows, increase flows to upstairs loops to max flow. Increase WC curve to happy temperature in house. Output of ground floor goes down because dT increases, compensated with uplift in flow temp. Upstairs floor out increases due to dT decreasing and increased flow temp.

[richo106]

Thanks again @JohnMo some good ideas and things to look at!

 

1. This is an option but this my last resort at the minute especially as the main rooms I want to increase heat is the bathrooms

 

2. I actually  have actuators on all the downstairs loops, controlled off neostat thermostats in the 4 areas. The hysteresis is currently 1 deg but think it can be changed to 0.5 

 

4. No I have not tried this, I have increased the flow rates on the FF but not decreased the GF

 

I think my next step is to change the WC curve to try and suit FF and then reduce GF flow rates and alter thermostats to 0.5deg differential see if I can control it that way

 

I am just struggling on what temperature to set my curve, currently it’s 35deg @ 0 and 20 @ 15 degrees ( I think) 

 

Should I just change it to 45 degrees @ 0 and go from there? Any ideas would be very helpful 

 

thanks again 

[JohnMo]

18 minutes ago, richo106 said:

This is an option but this my last resort at the minute especially as the main rooms I want to increase heat is the bathrooms

Why not make your wet radiators in bathroom dual fuel (electric element) or add another/bigger radiator? A thought for later.

 

20 minutes ago, richo106 said:

Should I just change it to 45 degrees @ 0 and go from there? Any ideas would be very helpful 

I would add a couple of degrees leave for 24/48 hrs see affects and go from there. If you have already tried that go further.

 

One thing with ensuites, if bedroom is cool the ensuite will never be hot, as the cool bedroom just pulls the heat from the ensuite.