It's been close to freezing all day and the Curve is still maintaining the whole house comfortably, it's now down to 39C at -5C (getting flatter) and still monitoring but based on yesterday's figures from Melcloud the cop was still under 2!! (See attached Screenshot)
I don't have any boost heating, only set for the legionella once every two weeks, hot water only set @ 45C and scheduled twice a day but firly short cycles as we never run too much off between cycles.
It's getting frustrating as based on the way the WC mode has performed over the last 4 days it seems like the house is not a heat sink as rooms have held up well as the curve has been reduced day by day.
Yesterday the unit show's 23.3 KW consumed and based on the smart meter reading for the day I would say that cannot be too far away from correct, I am beginning to think that Melcloud is not giving accurate outputs as I have read elsewhere that this has been questioned.
I have attached some melcloud report screenshots over the last two days and a typical hourly shot today which seems to show steady running.
I don't like to keep asking for help but just puzzled on the cop figures, I may have to accept that "it is what it is" and it's not costing a fortune (it is relative to last year 😫 ) as all rooms are heated to just above design temps still.
Its looking like todays spend is going to be around ten pounds but it's been very cold.
Your ASHP is cycling every hour or so but that (IMO) is fine and won't in itself cause a significant drop in efficiency. But your delta T looks very low, as little as 1 degree, even between cycles. That sometimes indicates flow is too high but that's about the limit of my understanding.
I don't know exactly how the standard Ecodan works out power generated but if it's using flow rates and delta T, the margin for error, especially where the delta T is small, is going to be large. What I'm saying is the COP you're seeing might not be that accurate. As Derek says, see what Mitsubishi says.
You may be correct Kev, I did not look closely at the DeltaT value, since the origin problem was cycling.
Without me having to look through the Ecodan manual again, do you know if there are any settings that can affect pump speed? Is there any indication of pump speed or flow rate that can be viewed?
Without me having to look through the Ecodan manual again, do you know if there are any settings that can affect pump speed? Is there any indication of pump speed or flow rate that can be viewed?
Indication of pump speed is in the Service menu, Running Information, code 0540, which displays the flow rate in litres/minute. There are pump speed settings in the Service menu, too, and if one has (a) circulation pump(s), then they will probably have speed settings on the pumps too. Sections 3 and 7 of the FTC manual give more detail about the required flow rates for each size ecodan.
Without me having to look through the Ecodan manual again, do you know if there are any settings that can affect pump speed? Is there any indication of pump speed or flow rate that can be viewed?
Indication of pump speed is in the Service menu, Running Information, code 0540, which displays the flow rate in litres/minute. There are pump speed settings in the Service menu, too, and if one has (a) circulation pump(s), then they will probably have speed settings on the pumps too. Sections 3 and 7 of the FTC manual give more detail about the required flow rates for each size ecodan.
Without me having to look through the Ecodan manual again, do you know if there are any settings that can affect pump speed? Is there any indication of pump speed or flow rate that can be viewed?
Indication of pump speed is in the Service menu, Running Information, code 0540, which displays the flow rate in litres/minute. There are pump speed settings in the Service menu, too, and if one has (a) circulation pump(s), then they will probably have speed settings on the pumps too. Sections 3 and 7 of the FTC manual give more detail about the required flow rates for each size ecodan.
as luck would have it I closed my laptop while page C8 was on screen.
pump speed ranges for the various HP models were on that page. Here’s a screen shot.
I have looked at the Service Menu and noted that the Pump speed is 5 and flow rate 19 l/min, I have dropped it down to 3 giving 16 l/min...................I noticed that on my commissioning document they have noted the pump speed as 3 but I have never altered it until today.
Yesterdays figures which was a cold day are fairly concering at 31.1 Consumed and 39 Delivered = Cop
1.25 ??? (See attached)
I looked back on melcloud to a similar period in january 2020 when I was running on auto adapt mode with timer schedule and you can see that cop was around 3 at that time..........I have never adjusted any settings prior to this exercise other than timer schedules and DHW temperature....I have it serviced yearly so the engineer could have tweaked
things...........not been able to get through to Mitsubishi yet.
I would imagine that the FTC figure for Consumed energy should be fairly accurate as metered input but imagine the delivered energy is less accurate due to the way it has to calculate ??
Based on my records HP Consumed has come out at 2819,3688,3776 & 3819 for last 4 years, last years is lower as it was a generally warmer year, corresponding overall cop figures are 2.19, 2.48, 2.69 & 2.73 (all inclusive of DHW and Heating) you can see the decline (2018 cop for Sep to Dec when installed was 3.11).
Many thanks my unit is the 85 with range between 10.8 and 24 not sure what determines the optimum but as just posted have dropped pump speed from 5 to 3 (19 l/min to 16) to see what happens to Delta T
Unfortunately we don’t have any cop data or energy figures to work anything out. We are still waiting for a replacement FTC6 controller since the one that was originally fitted back in mid November ‘22 didn’t have full functionality. Annoyingly that also meant we couldn’t use the Mitsubishi wireless remote either so we were given a 3rd party wireless remote.
All this without any explanation from anyone.
Apparently, I have recently found out, there was a shortage of key chip components. patience running very thin now…..
if the pump speed isn’t the cause one other possibility might be a buffer which as we know allows return water to mix with flow water… this can sometimes be too high a mix which will reduce the T-difference between flow and return…
. Does Dave know if there is a buffer or low loss headder tank fitted?
Thinking about installing a heat pump but unsure where to start? Already have one but it’s not performing as expected? Or are you locked in a frustrating dispute with an installer or manufacturer? We’re here to help.
