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Mitsubishi Ecodan ASHP general set-up and efficiency

ngillam · 2024-08-27T16:02:15Z

Hello all, new to the forum and keen to get the most out of our system. Long story short we live in a 185 sq metre new build barn with what I believe is an ECODAN 5kw ASHP coupled to underfloor heating. The building is very open plan consisting of two large bedrooms with two large bathrooms two large open lounges an open kitchen, boot room and attached art studio/workshop. We're located atop a hill in North Oxfordshire with south facing glazing to the rear so the sun does play it's part in cooking us in the summer. The installers provided an original set-up at the beginning of the year but without dwelling too much the property had a flood which resulted in the dehumidifiers and the heating ramp up to clear the effects of the flooding which is thankfully done with no lasting effects. It's been a number of months but I'm keen to get the set-up back to design intent, I'm a quick learner and would like to know all and eek the best out of what we have, we suffered a number of power-cuts recently and my partner jabbed away at god knows what to get things back on, she can't resist pushing buttons, it's an odd thing! but I wasn't around to prevent it. The attached images show the set-up, I've noticed since the powercuts the timers (of which we have two) need to be on for the showers to have hot water supplied to them. If off the water is cold despite hot water in tank...don't remember that being the case prior to power outage?? I have 2 x timers, one next to water tank (210 litre) and one above UFH manifolds so assuming each control each, water and heating? Each room has it's own similar thermostat and with it getting colder I'm keen to get the set-up running as efficiently as possible. There's two of us, occasional guests/kids visiting at weekends. Tank set to 48 degs with a drop of 7 before reheat. I think the timing thing has thrown me a little, which is master? The FTC or the individual timers I've indicated in photos? Can any kind soul see anything obvious or give a base setting I should be looking at to work from? Thanks, Neil.

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Air Source Heat Pumps (ASHPs)

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Anonymous 5011

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04/09/2024 10:08 am

Posted by: @ngillam

↑

Might be a stupid question but won't this affect the ability to heat hot water?

No it doesn't - what happens with a heat pump

It runs on a system where DHW takes priority. So when DHW heating is called for, the heat pump moves to heating mode. There will be a small slug of cool water that goes through the cylinder coil. But this water is likely to be no cooler than 14 deg, so its not as cold as the cold water entering the cylinder from the mains supply to replenish every time you open a hot tap. So zero issue.

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ngillam

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Topic starter 13/09/2024 4:32 pm

@johnmo

WC altered to what's shown in the photo and thermostats all opened up to 35degs. Timer set to permanently on so will see what happens. I tried to switch off the heatmiser timers but this stopped hot water getting to shower. Maybe these should be permanently on.....doesn't seem right though, hot water went off at the worst possible time...she's not happy.

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ngillam

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Topic starter 13/09/2024 4:36 pm

@gary

As post above, trying this curve but it's quite warm in our shire today. Do you have heatmiser timers? Seems they need to be on otherwise no hot water to shower....just sits in tank!

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Gary

(@gary)

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13/09/2024 4:42 pm

We have Heatmiser thermostats for ufh and rad zones all disabled bar 1 in the hallway. I don’t have anything controlled hot water other than the main ecodan controller

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ngillam

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Topic starter 14/09/2024 11:16 am

Morning, update. House is toasty, maybe a little too toasty with some rooms showing 22-23 degs, also went through 13KWH since yesterday according to ECODAN controller. Quite a lot considering I'd only used 60 since beginning of the month. HP seems to be more or less constantly on, I'm planning on spending the weekend sorting this so all advice and tips appreciated.

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Anonymous 5011

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14/09/2024 12:47 pm

I would say start adjusting WC at the cold end, but your warm end looks to hot, you need to adjust that to 20 OAT and 25 deg flow temp. Leave the cold end alone for now.

If you have been pumping 30+ degs in the floor it's likely to get hotter. Once you have adjusted the curve, the compressor and fan should stop, but make sure your circulation pump stays on. Don't do anything to the thermostats. Tomorrow morning if still warmer than you want adjust the the end of the curve down a couple of degrees and leave another 24 hrs

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ngillam

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Topic starter 14/09/2024 1:27 pm

@johnmo

Adjusted to this......Thermostats all running free at 35degs..........quite warm here in Oxfordshire though.

👍

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Anonymous 5011

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14/09/2024 1:51 pm

Warmer in Scotland today. Curve looks better. Just a matter of trial and error.

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ngillam

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Topic starter 15/09/2024 1:28 pm

@johnmo Afternoon, used 13kwh again, so 26kwh over the two days of this trial, very warm in the house again this morning and my partner has asked if i can suspend until it gets a bit colder. Most rooms are at or around 23degs, I'm away for 5 days this week and don't want to leave her in a stuffy house, too warm for her and she's from Florida!! Any other ideas? Used quite a lot of energy considering.

Cheers

Neil

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Anonymous 5011

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15/09/2024 3:05 pm

Your curve is obviously way to hot. You could probably drop a few degrees off the cold outside temp end.

While your away it's going to warm, I would bring your thermostats back to where you normally had them set.

For reference - My curve at the moment, starts at a flow of 25 and goes up to 29 when -9 outside.

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ngillam

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Topic starter 15/09/2024 4:41 pm

@johnmo I've managed to get the Melcloud thing working, looking at the room temp something is definitely wrong! At a bit of a loss.

rooms are too hot, not -39.

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Anonymous 5011

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15/09/2024 4:50 pm

-39 would possibly indicate it's expecting to see a temp and something is either loose or not connected. Maybe the installer has just circumvented all the built-in controls so he could overlay 3rd party stuff he is used too. Hopefully someone with experience your ASHP will add something.

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