Ecodan standby power consumption

[RobLe]

I think the heater is intended to keep the compressor above the evaporator temperature, so that liquid phase refrigerant doesn’t accumulate there, which could damage it on turn on.  Under normal cold weather conditions the compressor is hot anyway as it’s being used - compressors sometimes stipulate minimum airflow over them to cool them down or they run too hot.  I’m not sure what is ‘too hot’ though, specs I’ve seen just state fanspeed!  If an inverter model is run continuously, is the issue completely avoided - is it then only an issue for intermittent cold weather use?

Most heatpumps seem to have immersion backup elements built in - I’d be disabling that ‘feature’, just in case.
Our old (greenstar 18ri i think) gas boiler used 10W standby, i have no idea why.  There was just a hot bit of circuitry inside it, all the time.  No legislation on standby I think is the reason.

[Kevm]

On 29/04/2022 at 12:17, Kevm said:

My 14kW monobloc Ecodan with MMSP records minute by minute data.  When it's in 'stop' mode it averages a bit under 0.4 Wh per minute.  I know from the way it's wired up that that's all the power being used by everything.  About 25W I think?

 

Back to the original subject.  That was 24W when running, but in stop mode.  I'm on holiday now and the system is on standby.  Not a full power down but standby on the control panel.  Over the last 5 days Melcloud is reporting 2.9kWh used in total.  I make that 24W again so very consistent.  I don't think that's anything to be concerned about.  24W isn't any sort of heater or pump, just the FTC6 ticking over in standby.

Edited June 6, 2022 by Kevm

[SteamyTea]

4 minutes ago, Kevm said:

I make that 24W again so very consistent.  I don't think that's anything to be concerned about.  24W isn't any sort of heater or pump, just the FTC6 ticking over in standby.

That is what I would expect.  Still too high in my opinion, but not scary.

 

The manufacturers rally need to be clear about standby and other parasitic loads.

[ProDave]

28 minutes ago, SteamyTea said:

That is what I would expect.  Still too high in my opinion, but not scary.

 

The manufacturers rally need to be clear about standby and other parasitic loads.

That is interresting.

 

I have mentioned before my LG ASHP seems to use almost nothing in standby.  I have split metering that meters usage in DHW mode and useage in heating mode.  Heating mode in my case is any time other then when it is heating DHW so covers idle periods in the summer when the heating is turned off.

 

Unless the unit decides to turn on the circulating pump as part of it's anti freeze cycle on a cold night, then nothing whatsoever is metered on my spinning disc electricity meter, so the standby power consumption must be very low in standby.

 

I wonder if this is because I am using the hard wired "room thermostat" input to control the heating, and when the room thermostat is open, it is "more off" than it would be if just programmed off by it's internal timers? 

[SteamyTea]

9 minutes ago, ProDave said:

I wonder if this is because I am using the hard wired "room thermostat" input to control the heating, and when the room thermostat is open, it is "more off" than it would be if just programmed off by it's internal timers? 

Do you know what the room stat is actually turning off, or is that hidden deep in the LG controls?

[PhilT]

49 minutes ago, Kevm said:

 

Back to the original subject.  That was 24W when running, but in stop mode.  I'm on holiday now and the system is on standby.  Not a full power down but standby on the control panel.  Over the last 5 days Melcloud is reporting 2.9kWh used in total.  I make that 24W again so very consistent.  I don't think that's anything to be concerned about.  24W isn't any sort of heater or pump, just the FTC6 ticking over in standby.

This only adds to the mystery. We have contributors with 85's, one of whom (the OP) is consuming large quantities of energy on standby, the other is not. My 112 is using around 5Kw a day on standby based on actual mains meter readings, and your 14 is hardly using anything. Mitsubishi Ecodan tech help sent me this attachment on "Standby Power Consumtion" - would be interested to hear peoples views on this

Standby Power Consumption (1).pdf

[dpmiller]

the fact that they have some "monitored sites" sure makes it seem like they are aware of the issue...

[joth]

2 hours ago, Kevm said:

 

Back to the original subject.  That was 24W when running, but in stop mode.  I'm on holiday now and the system is on standby.  Not a full power down but standby on the control panel.  Over the last 5 days Melcloud is reporting 2.9kWh used in total.  I make that 24W again so very consistent.  I don't think that's anything to be concerned about.  24W isn't any sort of heater or pump, just the FTC6 ticking over in standby.

 

Interesting. My FTC6 is on a separate circuit to the outdoor unit, so I've not actually measured the power consumption of it, only the outdoor part.

The outdoor heatpump  is pretty consistently drawing 5.5W _average_ background load (about 25W peak background load).  I'll have to measure the draw of the indoor part. 

 

IMO 24W is believable but excessive for FTC6 on its own. 

 

[joth]

1 hour ago, dpmiller said:

the fact that they have some "monitored sites" sure makes it seem like they are aware of the issue...

This might be referring to the MMSP optional part of the old RHI scheme

https://www.ofgem.gov.uk/environmental-and-social-schemes/domestic-renewable-heat-incentive-domestic-rhi/applicants/eligible-heating-systems/optional-monitoring

 

Long term real world monitoring has got to be part of the industry wide process to prove how efficient (or not) these things are over the long term.

 

 

The PDF is interesting. The 1/3rd on duty cycle reflects my own measurements, except I see 27W peak draw not the 54W it mentions. Which is exactly double my measurements.

Their idea that electricity is 11p/kWh is out of touch with reality.

 

the xxxYHA models have much higher peak background draw, ~250W, which does seem to line up to a degree with some of the reports in this tread (except folks here are seeing that continuous, not with a 1/3 duty cycle).

 

So the VHA vs YHA model seems an important contributor.

 

 

 

[Stones]

I've been following this for a while as I have an 8.5 kW Ecodan, package cylinder and FTC5 controller.

 

I've been over and over my energy use and meter readings and certainly cannot find any evidence to substantiate the circa 250W standby, at any time of year. Having just checked, my unit is a VHA model.

[SteamyTea]

8 hours ago, PhilT said:

5Kw

KWh.

That works out at 0.208 kW 

[PhilT]

24 minutes ago, Stones said:

I've been following this for a while as I have an 8.5 kW Ecodan, package cylinder and FTC5 controller.

 

I've been over and over my energy use and meter readings and certainly cannot find any evidence to substantiate the circa 250W standby, at any time of year. Having just checked, my unit is a VHA model.

According to the data sheet I attached above yours is only 54W when on and 15W when off, so average only 35W (or 28W >21degC). Which precise full model description is yours? The mystery is why LA322's 8.5 (a VAA?) and my 11.2 (PUZ-WM112VAA) consume a lot more. I can't get a clear answer from Mitsubishi tech help but I'm not going to worry too much as the overall annual performance of my unit is spectacularly good and way better than my expectations.

[JamesPa]

The principal stated difference between the VAA and YAA models is single Vs 3 phase.  I would imagine almost all domestic users have a single phase unit, unless they have some unusual need for 3phase!  So most on here should have the VAA models.

 

Presumably the three phase bit in the YAA version is the compressor, the electronics and any minor components will most likely run off one of the phases.

 

However note that there are also V(Y)AA and V(Y)HA models, I can't work out the systematic difference between these (is it the refrigerant?) but this might matter!

Edited June 6, 2022 by JamesPa

[JamesPa]

Here are some excerpts from the 2019 and 2020 ecodan databooks showing some data for several models (but, sadly, still not the model number 'scheme').

 

Note that a variety of compressors are used, which could possibly explain the differences in standby consumption reported by the people posting.  Also is it possible that the standby pattern is determined by the controller not the unit itself (unlikely I would think, but possible.

 

I still cant work out the difference between the HA series and the AA series!

 

I suspect we need collectively to get to the bottom of all this to make sense of the Mitsubishi data and, more importantly, to work out what to expect with a new model.

Mitsubishi Models various.pdf

R410 R32 Models from 2019_2020 databook.doc

Edited June 6, 2022 by JamesPa

[LA3222]

I have no idea whats going on. When i isolate the outdoor unit the power consumption drops to zero. The controller is still on so I can only infer from this the FTC controller and other gubbins draw next to nothing. 

 

The second I provide power to the outdoor unit, pow, the vampire load is back.

 

I'm pondering going to the effort of sticking a meter in between the breaker and ASHP as final confirmation that what the energy monitor is telling me is true.

[SteamyTea]

7 minutes ago, LA3222 said:

I'm pondering going to the effort of sticking a meter in between the breaker and ASHP as final confirmation that what the energy monitor is telling me is true.

A proper meter?

[LA3222]

8 hours ago, SteamyTea said:

A proper meter?

Yes, around £20/30 and half an hour of messing around should give a definitive answer.

[LA3222]

I was away for a few days last week and turned the DHW off, heating and cooling was already off. The MEL cloud shows:

 

 

[Bonner]

12 hours ago, SteamyTea said:

KWh.

That works out at 0.208 kW 

 

Not wishing to split hairs ... but it’s kWh isn’t it?

[SteamyTea]

12 minutes ago, Bonner said:

kWh

Whoops, yes.

Even at the beginning of a sentence.

Yet another reason we should be using joules for energy, as that is allowed to be 'Joule' in that circumstance.

[JamesPa]

3 hours ago, SteamyTea said:

Whoops, yes.

Even at the beginning of a sentence.

Yet another reason we should be using joules for energy, as that is allowed to be 'Joule' in that circumstance.

If we were using joules most practical measurements in the current context would be MJ or GJ so always upper case wherever in the sentence it occurs!🙂

[SteamyTea]

15 minutes ago, JamesPa said:

If we were using joules most practical measurements in the current context would be MJ or GJ so always upper case wherever in the sentence it occurs!🙂

Yes. I like joules as a unit. It is more relatable to mechanical things.

[Luke1]

I've got a NIBE F2040 8kW model.

 

I have a shelly 3M monitoring the power usage. It would appear that when not in use the system is using 0.03kW.

According to the installer manual this would suggest that the crankcase heater is operational. I do not see any settings to disable this and wondered if anyone else had found anything?

 

I would expect the system to either be in Thermostat-off mode, or standby mode as per below table.

 

[JohnMo]

As I said loads of entries ago, the heater is stop liquid refrigerant forming in the lube oil.  If you could or did disable the heater, you would be buying a new compressor quite quickly.

 

The only way to stop this load is to switch the unit off at the mains.  When the unit restarts it will go through a heat up period to ensure the refrigerant is expelled from the lube oil before starting the compressor.

 

If you are using 5kWh a day on standby, while waiting to heat DHW, you may as just switch it off and use your immersion.

[RobLe]

@JohnMo 

You're entirely right, it is for that reason.  I found a ref to the same fact in a book that I've borrowed on heatpumps.  Annoyingly despite being a 400+ page book on heatpumps it didn't go into any more detail than that, so I'm left to speculate, and maybe you know more which would be great!  I made my own heatpump that has been running fine for 6 months with no heater  (don't think I'm an expert, all just diy)....

 

ahhh - a bit of googling before posting works wonders - there's a wiki article on it, I think says we're both right "crankcase heater":

"A crankcase heater is an electrical component in a compressor in an air-conditioning system, heat pump system, or chiller system. The crankcase heater is normally on all the time, even when the unit is not running, though temperature sensors and set points may turn it off when not needed. A crankcase heater's sole purpose is to prevent refrigerant migration and mixing with crankcase oil when the unit is off, and to prevent condensation of refrigerant in the crankcase of a compressor. The crankcase heater keeps refrigerant at a temperature higher than the coldest part of the system."