@derek-m 300mm I had the same issue. If the EPC states that insulation should be improved then you can't claim RHI - so I had to make some improvements then the guy came back and reassessed etc 

Same here, I had to improve mine, cost me about £150 and I did it myself in a couple of evenings

Currently, having spoken with the EPC guy, I have 100 to 120mm. In order to tick the right box to get my RHI I need to meet or surpass current building regulations, which is (supposedly) 270mm. I'm getting a 200mm Cross Layer added, which will give me ~300mm. It's going to cost me £10 per M² for materials & installation, & whilst I could do it myself for around £4 or £5 per M² just for the 200mm thick rolls, I absolutely hate everything to do with laying loft insulation, so I'm more than willing to pony up the cash to tick that box. Besides, my days are currently filled with decorating the kitchen. I've just finished tiling it, but now it's onto the painting...

Update from things at my end. Made my first changes to the set up. DHW settings lowered to 47*. Switched to the weather compensation on saturday. Really useful video which I think was initially posted by Kev. As you had all advised it was straightforward to do (yes even for me) Initial settings as 50* at -2* and 20* at 20*. Left thermostats alone and continued to log some data so I can see any changes step by step. No dramatic changes in consumption. Total daily ASHP kwh swinging between about 55 and 70kwh daily (big incentive to explore changes), temperatures around 2-5* during the day and about 0-2* at night. CoP average pretty steady at about 2.7 before and after these changes.

Also - picked up here that you can generate the PDF reports when access melcloud via PC rather than phone app which was all I'd been using.

Trying to correlate electricity meter with melcoud, MMSP, and the two readouts on the ASHP itself - might post about that another time it's not always adding up but need a couple more days to work it out. 

Today have proceeded to what I wanted to try based on my understanding of what I'm reading on the forum. Have tweaked weather comp curve to 42* at -2*, 20* at 20*. All indoor thermostats turned to max unless in a couple of room we don't heat where they are turned to zero. Not sure if that'll be warm enough but thought I'd start there and go up as needed rather than work down. Might need to weather family complaints but trying to be cost conscious.

Turning thermostats up to maximum feels counter-intuitive - impossible not to be nervous re consumption but we'll see where we are after 24 hours.

As always - in awe of the knowledge by the regulars on here - and massively grateful for the very generous sharing of that knowledge. 

Thanks again will update in a few days.

@rv3 

Hi RV3,

By turning up the thermostats you are merely removing them from the equation, and stopping them from interfering with the controller, and preventing it from actually carrying out the control function. Once your system is correctly configured and optimised it would be possible to remove the thermostats altogether, but probably best to keep them in place with a setting of 1C to 2C about the desired indoor temperature. If any rooms then suffered a dose of solar gain, the thermostat would help prevent the temperature from going too high.

@rv3 try to write down when the house feels too warm, or too cold, with the time & date (if you can, without changing anything). Then, you can cross reference that with the outside temp that the Melcloud system thinks it is. There is a way to tweak the middle of the curve too, not just the end points. You are also following the same logic as I am, with moving the lower end point further down from Zero.

@derek-m understood and thanks for the tip. The thermostats are old style dials with notches on so not quite as easy to calibrate as digital read out stats - hadn't thought about the rooms getting too hot but there's really only one room that gets and decent solar gain. All useful and have used a lot of what you've advised to try and figure out best approach - v grateful.

@justinsb thanks - will take that on board and interested to know how you get on with your curve given some of the similarities between set ups we have. 

Here's a snapshot of today - changes made at 10am. Will leave interpretation to others! Need to see over next couple of days how it affects house temp, overall consumption, and COP. 

Blue: flow temp

Black: return temp

Red triangles: DHW tank setting

Brown: actual DHW

@rv3 

Hi RV3,

From the graph you can see the immediate effect in that the water flow temperature was reduced from 42C to 35C, which should have improved the efficiency and COP quite considerably.

I am not that familiar with MELCloud, but it would have been interesting to see energy consumption and indoor and outdoor temperature over the same period.

@derek-m I think today's energy consumption data becomes available tomorrow I'll post that then thanks. 

@rv3 whilst you're doing this, & trying to convince your system to gently sip electricity, rather than guzzle it, I have found that writing down your electricity meter readings once a day really helps. If you have a ballpark estimate for how much the rest of your house usually uses, so much the better. That way, you can get a feel for how much a - 3°C day usually costs, or how little an +8°C one sets you back.

I have tended to start warm, & cut it down, rather than starting cold & warming it up. The reason is that it takes a day or so for things to stabilise, & there is an expensive peak of power use that it needs to raise the temperature by a degree or two.