Ecodan 14kw drawing 1.1A when off

[Simon123]

Hi all, hope someone can help,

I have a 14kw mitsubishi ecodan heat pump (single phase) and while giving it a service I put a current clamp on it and found its drawing 1.11A when in mode 00. i.e off.

This seems very high to me, anyone else experienced this or have any thoughts?

[r.bartlett]

crankcase heater ?

[The Viking]

~250W...

Probably a bit too much to be controls or even a crankcase heater... A circulating pump?

:cool:

[Simon123]

When it goes into compressor warm up mode 08, it draws 1.3A and you can hear it, but when in mode 00 it is silent. i've been checking it every hour today and it is always 1.1A.

[Tayters]

Hi Simon,

Came across this (on a Fujitsu split a few years back. Measuring with an amp clamp gave a high reading like yours when unit was at rest but if you used a power meter or whatever they are called - one that takes into account the power factor then actual current was very low.

I'm no expert in power factors but it's something like if the current and voltage are in phase then power factor is one and perfect for an amp clamp. If it isn't then your amp clamp gives a false reading. AC units have a part of the PCB to improve the power factor which is where all this grief stems from.

You can pick the meters up from Maplins or RS fairly cheap (search energy meters) or get stuck in and buy a posh one but it might pay to check this first before looking for a fault which might not be there.

Incidentally your electric meter at home takes the power factor into account so don't panic there. As for how does current lead or lag the voltage, well don't think I'll ever get my head around that one.

Cheers,
Andy.

[install monkey]

id be more concerned about the power consumption when its chuggin its nuts off :D

[MikeHolm]

Any beastie that sucks up that much power when off has something wrong with it. IIRC a crankcase heater would be maybe 50-60w, not 240w. And wouldn't power factor only account for a (perhaps) 20-30% measurement difference? The electronics of the inverter should help with that anyway.

OTOH, maybe someone has been feeding it IM's frozen pizza crusts:D

[joe-ice]

Not familiar with these but on some inverter systems i think that rather than use a crankcase heater they partially power the windings to heat the compressor and sump up.Maybe this is the current your reading

[hyperion]

I agree with joe, and recall that the Ecodan occasionally powers up the compressor to maintain the oil temperature as it does not have a crankcase heater. I remember from the training course that it is recommended when installing the unit to connect up the power and turn it on with the interconnecting data cable disconnected to allow the windings to preheat the oil. I have never bothered to check the current being drawn by this process.

[Glenn Moore]

Joe is probably correct in his thinking . On Maneurop Invertor scrolls the Danfoss invertor gives a 24 volt dc supply through the motor windings to act as a crankcase heater . Thats probably why the current draw seems high ?.

[Simon123]

It certainly sounds like it is powering the windings of the compressor to warm it it up, but when it has finished, and silent, it is still drawing power...and is still spinning my electrcity meter.

I noticed a transformer on the main board is very hot all the time, could be the source i guess? But doesn't seem right.

Simon

[install monkey]

https://drive.google.com/file/d/0Bz6TBzB0zKeAcy15eGRhMWRXYTQ/edit?usp=sharing
service manual for a 14kw ecodan

[install monkey]

When it goes into compressor warm up mode 08, it draws 1.3A and you can hear it, but when in mode 00 it is silent. i've been checking it every hour today and it is always 1.1A.
so in mode 8 it pulls an extra 0.2amp -if its pulling 1.1 amp continuously, where are you taking this reading from? at the circuit breaker, outdoor unit,meter tails?

[Simon123]

so in mode 8 it pulls an extra 0.2amp -if its pulling 1.1 amp continuously, where are you taking this reading from? at the circuit breaker, outdoor unit,meter tails?

I'm taking readings from the mains power cable where it connects to the screw terminals on the unit. I've also taken a reading at the meter tails and then switched the heatpump off at the isolator, and it dropped 1.1A

[Simon123]

https://drive.google.com/file/d/0Bz6TBzB0zKeAcy15eGRhMWRXYTQ/edit?usp=sharing
service manual for a 14kw ecodan

Thank you, i've been looking through this but can't find a 'stand by' power consumption...so still unsure if i have fault or not.

[install monkey]

from the drawing there is no crankcase heater, so the use of applying voltage to the windings is correct, is there an interface unit on it- as its powered off s1s2s3 is there any heater element in there as 1.1amp is high for powering electronics

[install monkey]

https://drive.google.com/file/d/0Bz6TBzB0zKeAVXY3UF9lajYtYU0/edit?usp=sharing
hydrobox

[Simon123]

No, the interface unit is just electronics and has its own mains power supply, the signal to the interface unit is 24V dc. Could the transformer on the main board be the culprit?

[Simon123]

https://drive.google.com/file/d/0Bz6TBzB0zKeAVXY3UF9lajYtYU0/edit?usp=sharing
hydrobox

I don't have one of these installed, the interface unit is a flow temperature controller,

http://www.celsiusair.co.uk/equipment/mitsubishi/ecodan/pdf's/Technical/Technical/Flow%20Temperature%20Controller%20Installation%20Operation%20Manual%20(PAC-IF021B-E).pdf

[Simon123]

Hi Simon,

Came across this (on a Fujitsu split a few years back. Measuring with an amp clamp gave a high reading like yours when unit was at rest but if you used a power meter or whatever they are called - one that takes into account the power factor then actual current was very low.

I'm no expert in power factors but it's something like if the current and voltage are in phase then power factor is one and perfect for an amp clamp. If it isn't then your amp clamp gives a false reading. AC units have a part of the PCB to improve the power factor which is where all this grief stems from.

You can pick the meters up from Maplins or RS fairly cheap (search energy meters) or get stuck in and buy a posh one but it might pay to check this first before looking for a fault which might not be there.

Incidentally your electric meter at home takes the power factor into account so don't panic there. As for how does current lead or lag the voltage, well don't think I'll ever get my head around that one.

Cheers,
Andy.


I thought i had convinced myself it was drawing current continuously, having tested it with current clamp & rms inline multimeter, finally tested it with a power meter, and shows 1.1A, 238V, but only 10W being consumed.

Having spoken to an electrical guru, put bluntly, the capacitors will be charging/discharging with the ac phase so the 1.1 A i've been reading is being thrown back and forth from the unit. A resistive load draws current and P = V.I, but a capacitive load is more complicated and way over my head, but am happy my heat pump is ok.

Thanks for your advice Andy that kept me questioning my readings and thank you to everyone else for your thoughts. All sorted.

Cheers,

Simon.

[Brian_UK]

Thanks for the update, always good to know when technology has been beaten. ;)

[Tayters]

I thought i had convinced myself it was drawing current continuously, having tested it with current clamp & rms inline multimeter, finally tested it with a power meter, and shows 1.1A, 238V, but only 10W being consumed.

Having spoken to an electrical guru, put bluntly, the capacitors will be charging/discharging with the ac phase so the 1.1 A i've been reading is being thrown back and forth from the unit. A resistive load draws current and P = V.I, but a capacitive load is more complicated and way over my head, but am happy my heat pump is ok.

Thanks for your advice Andy that kept me questioning my readings and thank you to everyone else for your thoughts. All sorted.

Cheers,

Simon.

Top man, glad you got it sorted. Rumour has it if the receiver lands in the neighbours garden when it explodes Mitsi give you a prize. :cool: