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Mitsubishi Ecodan - issues with flow/return difference and fluctuation

Salilah1173 · 2023-01-24T19:39:30Z

Asking for advice, before I speak (again) to our installers (!) We have Mitsubishi Ecodan 8.5 air source heat pump - currently not really performing well (they fixed a hardware issue a few days ago). My current worries are a) we can't seem to get to temperature above 19.8, with underfloor heating on all the time, and upstairs radiators set at 18C (they are fine, the upstairs temp is above 18) b) we are seeing flow temperature and return temperature tracking nearly exactly - most of the time - no more than 2 degrees difference and most of the time less - I thought the differential should be more? c) significant fluctuations for flow (and of course return) temperatures for a 24 hour period e.g. 19:00 last night %£c, 20:00 43, 21:00 50C, 22:00 54.4, 23:00 54.8, 24:00 50C, Same at 01:00, 03:00 down to 43C, 04:00 back up to 54C and so on! The hot water comes on at 01:00 to 03:00 so that makes sense, but we are seeing jumps 4:00 at 53.4, 5:00 at 48, 06:00 back to 54, 07:00 down to 48, 08:00 back up to 53, and so it continues. Is this "wrong"? Any ideas what it might be? Any thoughts much appreciated - I'll be calling the installers out, but would really like to know more of what I should be seeing as performance! thanks lotsSali

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Air Source Heat Pumps (ASHPs)

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Salilah1173

(@salilah1173)

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Topic starter 26/01/2023 6:12 pm

Thanks William1066 (like the name!)

Circuits I like <grin>

Our challenge (I guess for many) is that we didn't put in the underfloor heating - it was done some 15-18 years ago when the house was built - and there is no guide or instructions or plans or anything, it just is there... <grin>

so we are working backwards a bit - the good news is we are currently at 21.5C which is nice (!) in the main room...

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william1066

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Posts: 206

26/01/2023 6:38 pm

@salilah1173

21.5 is a nice temp for UFH for sure, though you could probably get away with a bit less given it is radiant heating.

I would just assume 200mm spacing, take the area of your room in sqm and multiple by 5. Then divide by number of circuits (assume equal length per circuit). Assume that 15 years go, they did not typically put pipes under fitted furniture such as cabinets. That should be good enough to start.

If you really, really want to know, a cheap thermal camera may do the trick for you.

TEST-METER.CO.UK "https://www.test-meter.co.uk/blog/how-to-trace-and-test-underfloor-heating-with-a-thermal-camera"

How to Trace and Test Underfloor Heating with a Thermal Imaging Camera | test-meter.co.uk

More and more properties now have underfloor heating installed as the most efficient way of providing consistent heat throughout a dwelling or commercial premises. As the pipes are hidden beneat

👍

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Kev M

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26/01/2023 7:08 pm

Hi Sali,

good to hear you made some progress. I think once you have all the pumps and valves sorted out things should be better. I'm afraid I know nothing about ufh; a bit of a black art to me!

👍

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Morgan

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27/01/2023 9:40 am

@william1066 is there such a thing as a cheap thermal camera?

Retrofitted 11.2kw Mitsubishi Ecodan to new radiators commissioned November 2021.
14 x 500w Monocrystalline solar panels.

2 ESS Smile G3 10.1 batteries.
ESS Smile G3 5kw inverter.

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iancalderbank

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27/01/2023 10:22 am

Posted by: @morgan

↑

@william1066 is there such a thing as a cheap thermal camera?

I have a seek thermal android. £250 so not exactly cheap. But it has been invaluable in tracing the performance of my heating system.

IR spot guns are also very useful, cheaper at around £40, and don't need a phone to work. I have one of those too (bought it first, then upgraded to the seek).

My octopus signup link https://share.octopus.energy/ebony-deer-230
210m2 house, Samsung 16kw Gen6 ASHP Self installed: Single circulation loop , PWM modulating pump.
My public ASHP stats: https://heatpumpmonitor.org/system/view?id=45
11.9kWp of PV
41kWh of Battery storage (3x Powerwall 2)
2x BEVs

👍

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HughF

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27/01/2023 10:30 am

@morgan yep, the infiray p2pro is the best bang for the buck. Not crippled by the stupid US export restrictions on frame rate and has a decent sensor. £230 ish, landed, all duties and taxes paid.

lots of reviews out there, YouTube/Google.

Off grid on the isle of purbeck
2.4kW solar, 15kWh Seplos Mason, Outback power systems 3kW inverter/charger, solid fuel heating with air/air for shoulder months, 10 acres of heathland/woods.

My wife’s house: 1946 3 bed end of terrace in Somerset, ASHP with rads + UFH, triple glazed, retrofit IWI in troublesome rooms, small rear extension.

👍

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Morgan

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27/01/2023 10:47 am

@hughf Thanks for the reply. It appears however this is only Android compatible. iPhone11 here.

Retrofitted 11.2kw Mitsubishi Ecodan to new radiators commissioned November 2021.
14 x 500w Monocrystalline solar panels.

2 ESS Smile G3 10.1 batteries.
ESS Smile G3 5kw inverter.

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HughF

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27/01/2023 10:48 am

@morgan yep they are usb-c only at present. The iOS version is ‘coming’

Seek thermal compact pro here, decent but low frame rate. I imported the infiray for my boss who is obsessed with thermal imagers and has an android device.

Off grid on the isle of purbeck
2.4kW solar, 15kWh Seplos Mason, Outback power systems 3kW inverter/charger, solid fuel heating with air/air for shoulder months, 10 acres of heathland/woods.

My wife’s house: 1946 3 bed end of terrace in Somerset, ASHP with rads + UFH, triple glazed, retrofit IWI in troublesome rooms, small rear extension.

👍

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Morgan

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27/01/2023 11:25 am

@hughf thanks. I shall have to research for ios but personal recommendation is always useful and possibly involves less trial and error. I live in an older house with a retro fit wet ASHP so it would be good to find heat leaks and the unit could possibly pay for itself in a short period of time.

Retrofitted 11.2kw Mitsubishi Ecodan to new radiators commissioned November 2021.
14 x 500w Monocrystalline solar panels.

2 ESS Smile G3 10.1 batteries.
ESS Smile G3 5kw inverter.

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HughF

(@hughf)

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Joined: 3 years ago

Posts: 489

27/01/2023 11:26 am

@morgan if you are on iOS then I can recommend the seek thermal. It’s much better than the flir one.

Off grid on the isle of purbeck
2.4kW solar, 15kWh Seplos Mason, Outback power systems 3kW inverter/charger, solid fuel heating with air/air for shoulder months, 10 acres of heathland/woods.

My wife’s house: 1946 3 bed end of terrace in Somerset, ASHP with rads + UFH, triple glazed, retrofit IWI in troublesome rooms, small rear extension.

👍

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Morgan

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27/01/2023 11:31 am

@hughf cheers I will have a Google. 👍

Retrofitted 11.2kw Mitsubishi Ecodan to new radiators commissioned November 2021.
14 x 500w Monocrystalline solar panels.

2 ESS Smile G3 10.1 batteries.
ESS Smile G3 5kw inverter.

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ChickenBig

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Posts: 292

27/01/2023 11:41 am

As an alternative approach, a standalone thermal imaging camera might be worth a look. No questions about software compatibility and support. Something like a UNI-T UTi120S (120 x 90) costs about £140 including VAT; the UNI-T UTi260B is about twice the price but has higher resolution (256 x 192) and does optical wavelengths too.

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