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Analysing MELcloud heat pump graphs

Boycey · 2024-12-30T20:33:14Z

Hi, Ecodan system with UFH.and using MELcloud to look at data. i've attached 3 graphs 2 from 4 and 5 am and one from 4pm, the 4pm one represents most of the day, well today anyway. Question:- what do these tell you? is one good and one bad? let me know what you think please?

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Air Source Heat Pumps (ASHPs)

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Gary

(@gary)

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05/01/2025 6:08 pm

@boycey what you have there is really bad cycling 10 times an hour.

if you increased the flow rate this will have only worsened it as it has less time to get rid of the heat to the UFH causing the return temp to be too high and the HP can’t modulate down any further.

Set your thermostat in the bedroom to the maximum temp you want it to be so you don’t overheat.

turn the the pump speed back down to 2 have you ever tried 1? What flow rate do you get with it set at 1?

Then see what happens at a range of milder OAT’s. If it’s still cycling more than a couple of times an hour then you will need to increase min flow temp up a bit.

This my ecodan for an hour this afternoon at 11C outside at 32C flow

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Boycey

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Topic starter 05/01/2025 6:18 pm

@sunandair stats set as above so there is just one set above bedroom comfort level, so that the circulation pump operates, I will then set that stat to a set back at night which will turn of the circulation pump and then the HP, .. I hope. No actuators, just the above, so hw will circulate everywhere. and then use WC for flow temp. Make sense?

There was a mesh steainer. And a few tiny bits in there.

I'm trying to get the sales team to get a service done, obviously Xmas has held that up. We shall see. I'm happy finding my way around the ftc6, it's just knowing what settings things are best at

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Boycey

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Topic starter 05/01/2025 6:27 pm

@gary yes pump was on speed 1 for a few days. And yes u I understand what your dying re putting flow rate up. What size HP have you got? UFH ? I just seem to struggle to get that deltaT bigger.

Are you using stats or open loop just running on flow temp

What have you set your WC to?

Are you SE uk as at 11c today, I'm on south coast had same oat

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Gary

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05/01/2025 6:38 pm

It’s an 8.5kw ecodan UFH and rads.

WC set at 32C at 3C, 45C at -10C.

Running on weather comp with thermostat set to 22C in the hallway. Once it gets to 22C which it has just done this evening for the first time in a few weeks it has turned the heat pump off.

Do not worry about delta T, you can see from the chart I sent it was only 3C at these lower flow temps I only get delta T of 5 plus when I get upto 40C.

if your heat pump is happy running at pump speed 1 without it giving flow errors then use it. That will get you the the largest delta T

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SUNandAIR

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06/01/2025 10:26 am

Posted by: @sunandair

↑

Posted by: @boycey

↑

”*

All actuators taken off all stats set to 17c except one in bedroom set to 21c 6am to 11pm, and setback to 19c 11pm to 6am. But I am getting graphs like I attached this morning every hour now except when dhw is on. “*

?

It's a newbuild, although system was put in 2yrs ago, we are first ones living here, I checked the y strainer.. circulation pump set to 2 for 9 L/M. The flow rate sheet I have shows 7 loops set between 1 and 2 L/M each adding up to 9 L/M.

Above highlight

does this mean you have certain areas not operating above 17c and only one area trying to get heating up to 21c? what % of the whole area floor area is operating at 17c? Or have I misunderstood this description?

thanks

Also was there any debris in the y-strainer, was there a mesh strainer actually in the y strainer housing…. Sometimes these are removed and not replaced… just checking.

PS as it’s a new build and you are the first occupier I think it would be worth pressing for service and induction on how to operate it.. by a Mitsubishi accredited installer.

hi @boycey I’ve read your latest reply. Not sure what you mean by “stats as above” I would suggest you find out if it’s ever been commissioned and if not then get them to set it up. since it’s been installed as a new build and again it would help for you to have a proper handover induction on how it has been set up.

good luck

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Boycey

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Topic starter 06/01/2025 11:04 am

@sunandair I meant as I had already mentioned. It was commissioned, I have been l, like most here trying to get it set up efficiently. Ie take the actuators of so it open loop, use one stat only as an over heat limiter, run flow temp as low as possible, "low and slow". But in doing so my graphs have been as I've posted, lots of cycling etc.

Yesterday I decided to use the one stat to set a setback last night, set it to 19c from 9pm-6am, interesting the room temp in all rooms only dropped by half a deg, this is with 11c oat but high winds, we are on the sea front so get the weather off the sea, (no snow for us atm) so that is encouraging, I will have to test like this when it gets a colder snap again. But I guess we have a very low heat loss. We are on the 9th floor, so I guess we must get some sort of benefit from flats below us, as apposed to ufh that's on the ground albeit insulated.

We were back up to set temp from 6am by about 8.30-9am. So maybe I just need to put it stat on timed for a couple of times a day, keeping the floor topped up.. I'll post a couple of graphs from this morning see how they look.