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Numerous issues – 11kW Daikin Altherma 3

newhouse87 · 2023-03-16T04:32:58Z

HI, Just found this forum last night and some of the posters on here have better knowledge then i have found anywhere else. Don't understand alot of it yet but anyway i had 11kw daikin altherma3 low temp split installed last February and moved into the newbuild in June. Only since winter came i have noticed many issues. For past 3 months some rooms were not heating at all but in the last 2 weeks i have figured out stats were wired to wrong ufh loops, have that sorted now thankfully. Installer left me no paperwork and told me nothing about system. Im still thinking its not as efficient as it should be. Some rooms take up to5-7 hours to get up to 21degree setpoint from say19degrees. Only from reading this forum i think my dhw schedule is bit inefficient. DHW 7am 50deg,2pm 50deg, once a week at5am 60deglegionella cycle. All schedules are 2hours long i think. Reheat set point is at 45 so from reading here im thinking that's too high and may override my ufh flow too much. Im on weather dependent mode but yesterday was 11 degrees and my lwt was 32. Is that bit cold and maybe why my ufh slow? Also noticed my copper flow pipe from unit gets hot but i could go back into room 10mins later and its alot cooler, any reason for this? Apologies about all the questions but i had extreme bills in nov/dec and want to figure this out and this forum seems by far the most knowledagble. Using 70kwhs a day on cold days in a well insulated 2600sq ft bungalow seems bit much. Getting some big spikes especially at night time/early morning. Thanks again.

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Derek M

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18/03/2023 1:23 pm

Posted by: @newhouse87

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@transparent i think there is a red ring around each flow gauge that maybe i need to turn, they seem stiff however.

Get the manufacturer's name and model, then download the manual which should explain how to make adjustments. As I stated in my previous post, don't start adjusting flow rates until you have your heat pump operating continuously in WC mode.

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Transparent

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18/03/2023 1:26 pm

It's not common to have any manual adjustment on an UFH manifold like that.

Don't start unscrewing red rings unless you are completely certain of what they're for!

Save energy... recycle electrons!

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newhouse87

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Topic starter 18/03/2023 1:31 pm

@derek-m is my weather curve at 44 at-3 and 28 at 17 not ok? Also why would say my lwt be at 48 other evening and 28 today, or will that go up once there is a call for heat? Maybe the system is okish, how long is normal for 25sqm room to heat up 2degrees say? 3 loops. I know you cant give exact time but would 4-7hours be normal?

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newhouse87

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Topic starter 18/03/2023 1:40 pm

@transparent

seems easy. Might lower it to 1.5. Bathroom right beside manifold so no way should it have same flow as loops farther down the house.

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newhouse87

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Topic starter 18/03/2023 1:47 pm

......

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Transparent

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18/03/2023 1:50 pm

Posted by: @newhouse87

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Maybe the system is okish, how long is normal for 25sqm room to heat up 2degrees say?

I'm not sure that the floor area of the room is the most significant factor.

The mass of the concrete pad, the floor surface which covers it and the proportion of total energy which is available to that room-loop would seem to be just as significant.

I'd also like to gently query the concept of a room 'heating up'.
That phraseology is derived from the days of gas boilers and coal fires.

The design of a heat-pump system is based on keeping rooms at the constant temperature you've set them at.
It doesn't 'heat up' because it doesn't cool down.

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newhouse87

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Topic starter 18/03/2023 1:57 pm

@transparent yeah the rooms with tiles heat up quickest. I mean when stat calls for heat the room to warm up a bit more shall we say. Im considering having all loops open in living areas as william suggested.

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Derek M

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18/03/2023 2:00 pm

Posted by: @newhouse87

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@derek-m is my weather curve at 44 at-3 and 28 at 17 not ok? Also why would say my lwt be at 48 other evening and 28 today, or will that go up once there is a call for heat? Maybe the system is okish, how long is normal for 25sqm room to heat up 2degrees say? 3 loops. I know you cant give exact time but would 4-7hours be normal?

The first thing that you need to do is turn up all your room thermostats so that they are all calling for heating, then wait, probably several hours for the room temperatures to stabilise. If the rooms are too warm then reduce the WC curve setting at the low outside air temperature end, then wait several hours again.

The objective is to balance the heat energy produced by your heat pump, to the heat loss of your home. As I said previously, this is not a 5 minute job.

The slope of your WC curve is dependent upon the heat loss of your home. Do you have any heat loss calculations?

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newhouse87

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Topic starter 18/03/2023 2:07 pm

@derek-m oh man sounds difficult, im presuming the installer had the calculations, is it on the ber cert i posted? When rooms get up to temp, dont the loops just close so they wont overheat. What would you think of leaving all living areas loops open together or would that be costly?

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Transparent

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18/03/2023 2:08 pm

Yes, tiles are good conductors. 🙂

Do you know if the concrete pads have a thermal break (of insulation) in the rooms where they abut an external wall?

Look again at the photo I posted earlier.
There's a 100mm high upstand of insulation around the border, before the concrete gets poured.

In the following photo you can see this 30mm-thick barrier being installed.

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newhouse87

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Topic starter 18/03/2023 2:20 pm

@transparent yes we have upstanding insulation, i done it myself. Thanks again to everybody here for all the info, hard to take it all in today 🤣. so far i have changed my dhwtemps and schedule and disabled buh so hope that helps. Now im strongly considering having no zones in living areas. Will adjust bathroom flow rate as that room gets to hot and quick. If bathroom heats up, will the water eventually flow to colder rooms more?

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