Underfloor Heating downstairs, Aluminium Radiators upstairs

CHorn

https://www.boards.ie/discussion/comment/121480107#Comment_121480107

Thanks so much for the link (and to your Q it's a screed floor upstairs). And yes, as you say we really only need for Nov-March, and ufh up might have been the answer. They just made the same assumptions as they would with a regular house that heat would rise, forgetting that most folks (?) prefer a colder bedroom so you're not going to get much bleed up in the upside-down house scenario.

Cowboys? I'd use another word myself, but no kidding. @hurikane, feel even better here. Joule finally set up an appointment to come show us how their magical black box worked- all singing and dancing without a user manual or written instrux apparently- one year after it was installed. So with the builder, both owners, the entire plumbing crew (3), both quantity surveyors and the architect plus assistant standing around on-site waiting for the Friday 2pm performance to start (read scheduled meeting), we got a no-show.

I wanted to tear the entire thing out just off the back off this lack of service, but (alas, sigh, sob) was persuaded otherwise. We live and learn...

hurikane

My heat pump is in a few years so is a gen 5, yours may be gen6? Got the manual here https://www.cairnhomes.com/media/kwqde4nb/joule-heat-pump-installation-manual.pdf

halkar

You should be able to set different heat curves for your ufh and rads. I am not sure if you have access to heat curves in your controller as it may need to be enabled with installer option. If commissioned properly you will have two zones in heat curves setting one for rads one for ufh. This is separate to your zones controlled by termostats. You can increase water temp for rads in there.

CHorn

https://www.boards.ie/discussion/comment/121482044#Comment_121482044

https://www.boards.ie/discussion/comment/121481993#Comment_121481993

@halkar- thanks, with information in manuals below, I'm gonna take a look at these. But given I don't have much faith in Joule at this point and a lot of this is above my pay grade, I may hire someone independent to take a look at all this. I'll see once I've digested manual below (if I can!).

Thanks a million @hurikane, using this as an example, was actually able to track down a Gen 6 version for my model Samsung AE120RXYDEG here (just Handover Document- warranty and some control panel instrux): G6 Handover Doc.indd (hubspotusercontent-eu1.net)

Also see this far more comprehensive Installation Manual here: Samsung-Gen-6-Heat-Pump-Installation-Manual-min.pdf (theunderfloorheatingcompany.co.uk)

Hopefully this will be of use to others.

loyatemu

people saying bedrooms should be 18C - yeah if you're in bed maybe. Kids and teenagers spend a lot of time in their rooms and 18C is not warm enough to be comfortable. Similarly if your wandering around your room after a shower, getting dressed etc. We have our bedrooms set to 18 overnight but 20.5 for the times of day when there are people using them.

The OPs problem is that he can't get them above 19C; if he wants to have the rooms at 23C that's his prerogative (my parents have their house at 25 the whole time, I have to start taking layers off when I visit them!). A properly designed system should be capable of doing this.

halkar

In the installation manual look under System 2 or System 4 which has details on two zone radiator and ufh configuration. There is 8c difference in flow temps as reference. I don't have Samsung hp but I have mine set min 40c. Manual has details on how to enter settings mode. You may need to increase the minimum temp for radiator zone. Temperature fluctuations between min and max are set in heat curves but not sure where it is as there is no reference to it in the manual.

You should also check the flow rate to your radiators if temperature settings are ok. If flow is slow radiators will feel cold even though hp sending hot water. If radiators are in loop they may need balancing. Manual says separate pumps for radiators and ufh but installers don't always follow manuals.

halkar

In the installation manual look under System 2 or System 4 which has details on two zone radiator and ufh configuration. There is 8c difference in flow temps as reference. I don't have Samsung hp but I have mine set min 40c. Manual has details on how to enter settings mode. You may need to increase the minimum temp for radiator zone. Temperature fluctuations between min and max are set in heat curves but not sure where it is as there is no reference to it in the manual.

You should also check the flow rate to your radiators if temperature settings are ok. If flow is slow radiators will feel cold even though hp sending hot water. If radiators are in loop they may need balancing. Manual says separate pumps for radiators and ufh but installers don't always follow manuals.

ZX7R

Hi op I had the same problem although with a completely different heating system.

Duel gas and solid fuel stove.

Long story short after having every type of plummer technician checking our heating system which was running perfectly.

It turned out to be the ventilation. Causing a cold air loop witch would drop the temperature by 4c compared to the rest of the house that was not affected.

Could worth worth thinking about.

CHorn

https://www.boards.ie/discussion/comment/121485973#Comment_121485973

No kids=no problems. So beds low temps and everyone is up and out early, no need to heat during day.

Problem is upstairs living areas (beds are downstairs) set to 20.5 struggle to get over 19 in cold snaps. 23 or 25? Lordy, no, never, that's for swimsuit fetishists or nudist colonies.

https://www.boards.ie/discussion/comment/121486141#Comment_121486141

Thanks, ventilation and insulation look sound, but I'll keep this in mind.

CHorn

https://www.boards.ie/discussion/comment/121486091#Comment_121486091

Thanks a million. Exactly along the liners of what I'm thinking. Hopefully a Joule specialist will be by sometime in 2024, we're going to try both these ideas first as simplest most obvious fix (if possible) is to raise water temp going IN to upstairs rads.

Though have to say flow seems OK as they're not cold, just the c35 as mentioned in posts here. Will check on pumps.

mickdw

You need bigger rads. No other answer really.

With low temp flows from.heat pump you need twice the rad area that you would traditionally have.

I'm no expert but I'd imagine you should be able to use the zoning to focus on bringing up temp of living areas when bedroom areas are zoned off.

Imagining a luck warm rad, it stands to reason that much more rads are needed.

halkar

You can check out this video. Not sure you have the same controller but should be similar. First setting he is doing is for the curve. Second one he is doing is for ufh. There is another setting there he didn't go into which i think it was for rads. You can check your settings without changing to see how it was configured.

https://m.youtube.com/watch?v=FcXAtVjdRE8

John.G

https://www.boards.ie/discussion/comment/121488041#Comment_121488041

If, realistically, you wont get less than 3C rad flow/return temps dT then here is what you will get at 4 different flow temps, assuming a room temperature of 20C in all cases.

(T8.5 rad) 30C/27C/3C/10% (A 1 kw rad will emit 100watts)

(T13.5 rad) 35C/32C/3C/18.2% (A 1 kw rad will emit 182watts)

(T18.5 rad) 40C/37C/3C/27.5% (A 1 kw rad will emit 275watts)

(T23.5 rad) 45C/42C/3C/37.5% (A 1 kw rad will emit 375watts)

CHorn

https://www.boards.ie/discussion/comment/121488041#Comment_121488041

Yes, 1 option- possibly the best- but a little impractical for us unfortunately with limited space and alu rads in already (under counters, along 2 walls, we'd have to increase height-wise which wouldn't look good aesthetically). Along with replace system (within warranty, my original preferred but alas past that now), increase water temp into rads, and supplement heat somehow (we have a 3-sided electric fire insert for show but does heat too).

https://www.boards.ie/discussion/comment/121488422#Comment_121488422

Really useful and thanks, could be key to getting more heat in the water going in to rads. Will check current settings.

CHorn

https://www.boards.ie/discussion/comment/121488841#Comment_121488841

Thanks, quick Q, I get the 30/27/3/% but what's T8.5 rad or T13.5 rad?

blackbox

Probably a stupid question, but if you set the upstairs room thermostat to 26 degrees, what temperature is the room at 24 hours later. This would be a way of checking if it was a control issue or a capacity issue.

John.G

https://www.boards.ie/discussion/comment/121492797#Comment_121492797

A T50 (normal rated rad) is the mean rad temperature - the required room temp, the mean rad temperature is the (flowtemp+the return temp)/2 and the required room temp is normally taken as 20C. So a T50 rad will require a flowtemp of 75C and a returntemp of 65C, (75C+65C/2 = 70C, 70C - 20C =50C so a T50 rad. The above rad (30+27)/2 - 20, = 8.5C so a T8.5 rad. Rad output is exponential (to the power of 1.3) so a T8.5 rad will give (8.5/50)^1.3 x100 = 10% (of a T50 rad). and so on.

CHorn

https://www.boards.ie/discussion/comment/121492856#Comment_121492856

Only a problem when outside temps approach 0. Temp upstairs is set to 20.5, and works fine, EXCEPT when outside temps get real cold (0), then the rads even on 24/7 struggle to maintain c19. So definitely a capacity issue as discussed above, nothing wrong with the controls, though as has been pointed out we can try to change the controls to get hotter water into the rads.