Mr Slim Help needed

[Bakerbj]

Got a call out to a Mr Slim 410a Invertor. Not been working for about a year !!!

It was completely empty of gas, no pressure at all !!!

Pressure tested at 25 bar, in 2 hours it dropped 1 bar, Vac'ed out for 2 hours then charged with 5 kg of gas.

When the unit comes on the fans run then it cuts out when it trys to fire up the compressor. It does this 10 times.

I have 240v on each of the phases, and only 1 Ohm resistance across the windings.

Is there something that will hold the compressor off ?

Sorry but i have never worked on one of these before, any help would be great

[Brian_UK]

Pressure tested at 25 bar, in 2 hours it dropped 1 bar Well it seems that you haven't found the leak yet then :(

[The Viking]

Where was the leak?

If it been empty for a year, collecting moisture and creating acid it might well be seized. (it sounds like if it is)

In cases like this a simple vacuum isn't enough, ideally the oil would be changed but as a minimum it should be kept below 200 microns for a day or so with the crankcase heater on and OFN blown through it at regular intervals.

With the modern oils, if it doesn't get done properly the oil will become acidic and you will end up pumping acid around the system.

If it is sized then it's not much you can do but changing compressor and give it a good clean out to get rid of all old oil.

Good luck,

BTW, what fault code did it flag up?

(Brian, you are a faster typist than me but I agree, statements like that makes you wonder)

[Bakerbj]

I could'nt find the leak via just pressure testing, so I charged it so i could use my leak detector, With the compressor not working I recovered th gas, so not to lose any !!!!

There was not fault code, there are 3 units running off the one controller.

My question is: with all 3 phases getting 240v then the compressor should work, unless it is knackered, but then I would of expected the winding to give more of a resistance than 1 ohm's

[Thermatech]

Did you do a mega test of compressor windings to ground ?
This test will simulate compressor running under load & show up any problem with the motor windings to ground.

Having said that we would expect the outdoor unit & remote controller to report an overcurrent fault if the compressor is locked.

If its a PUHZ-RP outdoor unit the fault codes for overcurrent will be one of these UF , UP , UH or U6 at the remote controller.
On the outdoor circuit board the green led will blink 3 times & the red led will blink 4 times.

[Bakerbj]

I have a constant 240v on all three phases when in test mode ( sw4 1 on )

The guy at Mitiz said he thought it was the power board, as he thought I would only get about 110v, but there was another unit next to this one and it gave the same readings.

The lights dont blink.

Funnly enough I went to another Mitz unit today and that was empty of 407 and the light blinked 4 times green then 4 times red, Do you know what that means, where can i download the fault codes ?

[superswill]

as daft as it sounds are the services valves open? i ask as i had this on a site "that was working fine"

[Thermatech]

Its best not to get too warried about exact voltage being supplied from the inverter to the compressor because every multi meter will give a different reading.
It depends on the specification of the meter.
But the inverter should supply a ballanced voltage on all 3 phases.

The 4 green blinks & 4 red blinks is the old P8 fault & the indoor reports P8 when its does not see enough coil pipe sensor temperature dif when the outdoor unit starts. Classic SOG fault.

[Bakerbj]

the first one was a PUHZ RP 100 if i remember right, didnt look at the other one sorry. I was thinking of going on a training course with Mitzs. Would this one help

MPSF - M Series and Mr Slim Service & Fault Finding
Overview

This course will cover:

Operation data retrieval and recording
"Hands on" demonstrations
Inverter diagnostics
Compressor diagnostics
Diagnostic procedures using the "A" control service tool (Mr Slim)
Diagnostic procedures using the remot controller
Cost: £135.00 ex VAT per person

Or can some one recommend another one, it is only the Mr Slim unit I come across.