@sunandair some graphs from last night,do thesel ook a bit better. not sure why flow and return are the same on the last one

It was colder last night so It looks like the flow temp is up as per westher comp. Maybe as @Gary  says below ecodan doesn't like minimum flow temp too low, mine at 25c at 15c oat then goes up to 34c at -6. Last night git to 0c oat

if you click on tank temp and set temp in the legend it will remove them from the plot it will rescale  you will then be able to see what the flow temps are doing but it’s cycling several times an hour by the look of it.

I think you will have to run your heat pump at a higher flow and use the thermostat to turn it off, if it’s well insulated then that will be a better strategy for the life of the heat pump and possibly cheaper 

@gary my thought process was to run the flow temp low ie 25c but for longer, if I raise the flow temp it will run for shorter periods and hotter. I was trying to get the flow temp just right so it never or rarely reached the room stats, which I've set I bit higher than our comfort level. Thinking it will be then putting in just what the system needs to keep that temp without the stats cutting HP off/on. I think this was working OK dieing the day.  But at night with a set back of a deg or so, is what could be causing the short cycling. As @sunandair says, maybe drop the setback on the stats a bit lower so it doesn't get that low and maybe won't cycle. Then on morning start calling for heat again as above.

@gary

this is as you suggested, the last graph above without the Hw bits. not a good delta T

@boycey If you are running at 26C and the house is 20C then your UFH isn't going to be able to get rid of any heat as the room temp is too close to the floor temp so delta T will be very small.  If it was running at that time and your flat is warm then I wouldn't worry its not cycling in that hour but was it actually running?

@boycey 

I’ve posted the graph before the one you’re discussing with @gary

the graph shows the apparent stopping of the HP which looks like it’s reached room temp and has reverted to standby at 8:43 and continues in standby on the page you are discussing (9:00 page) 

Its quite common for the temps to move up and down small amounts as the water circulates with the HP not operating. There will be water circulating at slightly different temps as the circulating pump continues to operate.

you could try printing off a 24 hour internal temperatures graph like this one which tells you when the HP is working or in standby the gaps in the blue and black graph is when the HP is in standby.

hope this helps

ps the graphs you posted to me showing 3 cycles are when the HP is operating at an acceptable cycle. 👍

Perhaps the higher flow temperature on the colder night is allowing your HP to operate for longer periods. You could easily emulate this by just adding +3c on the front screen of the FTC.

This will add 3c to the settings of the WC curve without altering anything permanently.

Once you’ve established what flow temp works best, you could then, for example, look at 2 setbacks per day that could fit well with household comfort periods that work best for you. You might also be able to align these heating periods with cheap tariffs if they are available to you….?!

Posted by: @gary

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if you click on tank temp and set temp in the legend it will remove them from the plot it will rescale  you will then be able to see what the flow temps are doing but it’s cycling several times an hour by the look of it

Thank you - I wasn't aware that clicking /tapping the legend on the MELcloud graphs would turn the plotlines on and off!  I was missing the return temp on the MELcloud app and thought my thermistor had gone phut but I must have tapped the legend and turned it off by mistake...

@sunandair ive taken the tank temp off so the graph can be looked at better as suggested, and ill attach the internal temp for 24hrs, these are from the past 24hrs more or less and before i start to make further adjustments, ie maybe raising the flow temp to see how it changes things, some of these graphs are all over the place. last couple of nights have been down to around -2, daytime about 4 or 5 oat, but very sunny so had a lot of solar gain, i had to open windows today, lounge kitchen diner area (one open room south facing) got to 26c.

WC

25c @ 15 v 34@-6c oat N=-2 D= 3 very sunny

@boycey hi.

thats a better picture.... in case you didn’t know , your first picture is showing a defrost.... where the blue flow temp line drops below the return temp line.

Its quite normal to look like that.

Also your 24 hour internal temp graph shows your HP was in standby mode from 8am until 3pm. Presumably up to target room temp or timed to be set back. There also appears to have been a DHW Cycle at 11am for an hour.

it looks like the colder weather has definitely improved your cycling. Most likely because your flow temp is now above 31c on your WCcurve.

the cycling has considerably reduced too. What do you think about it now can you see a better picture yourself? Are you still getting the rooms up to your target temperature? 

Your HP appears to be delivering a DT3.5 (more or less) which is a healthy modulated output since you don’t require more than that if you are getting the room temperature you need. The challenge is finding the stable operation of the HP at all outdoor temperatures. 

The reduced cycling and low DT is ideal. So if you can get your HP to do this when it’s MILDER OUTSIDE you may find raising the flow temperature on your WCcurve at the milder end will reduce the cycling. 

I hope this helps

@sunandair Hi, yes flat is nice and warm, maybe slightly too warm, a couple of rooms getting to 22 plus. not very sunny today, so be interesting to see how todays graphs compare to yesterday. Delta T less than 5 is ok is it? im assuming if the flat was cooler and then warming up the delta T might show greater, but as its just ticking over the return isnt cooling down that much, or have i got that theory wrong?  would you mind commenting on a couple of other graphs as to what is happening please just so i'm more familiar with what events look like, really appreciate the input and help.  As a theory, if heating the floor using the flow temp and not stats if i start to raise the temp when milder, wont we get too hot? it seems a fine balance, 25c seems to be enough BUT then we get the cycling?

do you think i should up from 25c to 30c as the min flow temp, and ramp up around 0c?

@boycey 

incidentally, if you do select graph unused graph lines you can keep the scale of your print page the same scale... see below

Different days same scale