Posted by: @derek-m

@markc 

Mark,

It is always a good feeling when you solve the problem and fix it yourself.

Once you are certain that the valve problem is resolved, i would suggest that you set your heating water flow temperature to 35C and DHW to 50C again, and monitor your system to see how this affects the COP values. Because of the valve problem, and the original settings by your installer, your system has been operating with a water flow temperature of 50C under all conditions. It will therefore be highly useful to see the different COP values obtained between DHW production and heating. If, as I suspect, it shows quite an improvement in efficiency, it may be cost effective to have the additional equipment installed to provide active weather compensation.

Without wishing to upset 'she who must be obeyed', you could try manually lowering the water flow temperature for heating, to the point where it no longer meets the heat demand. Obviously, because home heating systems respond slowly to changes in temperature, it would be a matter of making a slight adjustment and then waiting several hours to see the effect.

Yes the DHW reached 51º and the value closed properly. I'll keep my eye on that this week.

As the for flow temp, at 40º set this morning the UFH areas are up to 22º so that seems to be OK with outside temp around 10º today.

I've now set the flow temp to 35º and will leave it overnight to see how it performs and get some MelCloud data in the morning.

Thanks Derek

Posted by: @derek-m

Mark,

A quick question, how did you produce the graphs? Were they derived from your Ecodan controller?

They come from the MelCloud app (part of the MMSP). There is a phone version and web browser version.

Temperature History is useful for DHW tank temp and outside temp history.

Operation mode whether the pump has been off, Space heating, DHW heating or legionella prevent.

Internal Temp useful for flow and return temps.

Hourly Temp as above but breaks down the last 24 hours into hourly charts.

Energy Usage shows used and delivered energy as well as a COP chart.

@markc 

Thanks Mark,

You will no doubt find that to be useful for fault finding and also for optimising the operation of your system.

@markc 

Evening Mark,

I have been reading a little deeper through the manual for the FTC5 controller and I do believe that you should be able to utilise the weather compensation curve with your present system without additional equipment.

Before we go through the required adjustments tomorrow, can I confirm that we both have the same manual. On the front page of the manual that I have it states:-

FLOW TEMP. CONTROLLER [MASTER] (Cased)
PAC-IF061B-E
PAC-IF062B-E
PAC-IF063B-E

The manual is 68 pages long.

Posted by: @derek-m

@markc 

Evening Mark,

I have been reading a little deeper through the manual for the FTC5 controller and I do believe that you should be able to utilise the weather compensation curve with your present system without additional equipment.

Before we go through the required adjustments tomorrow, can I confirm that we both have the same manual. On the front page of the manual that I have it states:-

FLOW TEMP. CONTROLLER [MASTER] (Cased)
PAC-IF061B-E
PAC-IF062B-E
PAC-IF063B-E

The manual is 68 pages long.

No it's FTC6

PAC-IF072B-E

https://library.mitsubishielectric.co.uk/pdf/book/Ecodan_FTC6_PAC-IF071-3B-E_Instruction_Book_RG79F363L01#page-1

This is looking very exciting 😆 . I'll wait until tomorrow to get a full days worth of data and then share a comparison with a previous days performance with a similar outside temp.

Posted by: @markc

This is looking very exciting 😆 . I'll wait until tomorrow to get a full days worth of data and then share a comparison with a previous days performance with a similar outside temp.

Good Morning Mark,

Could you please provide data over a longer period, from before you resolved the problem, so that other forum users can see how a fault can drastically affect the operation of their system.

Do you still wish to go ahead with setting up weather compensation on your system, and if so, do you wish to do it today or leave it until later?

Posted by: @derek-m

Posted by: @markc

This is looking very exciting 😆 . I'll wait until tomorrow to get a full days worth of data and then share a comparison with a previous days performance with a similar outside temp.

Good Morning Mark,

Could you please provide data over a longer period, from before you resolved the problem, so that other forum users can see how a fault can drastically affect the operation of their system.

Do you still wish to go ahead with setting up weather compensation on your system, and if so, do you wish to do it today or leave it until later?

Thanks Derek, I have been collecting data for the last 4 weeks, changing one setting each week. So I'd like to collect this weeks data as a comparison before turning on the compensation curve if that's OK with you.

So ideally Monday 8th Nov would be a good target.

Once I have this data I'll share it in one post.

@markc 

That is fine Mark, whatever suits you best.

@markc 

Hi Mark,

It would be interesting to see the corresponding temperature graphs to go with your consumption and COP data.

Although only a 1 day snapshot this is interesting (not in a logical way though).

If we ignore the orange DHW usage as this was caused by a faulty valve being continuously open.

21/10/21. Flow temp 50º, outside temp 9º, UFH heating set at 22º continuously, 24hrs. 

03/11/21. Flow temp 35º, outside temp 9º, UFH heating set at 22º continuously, 24hrs. 

Running at 35º the COP looks to be around 3.5, using 23.8kWh

Running at 50º the COP looks to be around 2.5, but only uses 22.1kWh

Next Monday I will have a weekly comparison.

@Markc, very interesting.  Was your house warm enough with the lower flow?  To use the car analogy quoted by someone else, you have better mpg but you're driving further.

How do you scale the MELcloud output to look like that?  I could post some of mine but they won't look as neat as yours.  My overall consumption is similar but much spikier as I've been varying the room temp using the thermostats. 

Have you looksed at the csv output?