Mitsi Heavy E57 fault code in Error Log on wired controller

[back2space]

Evening all...

Unit at work doesnt cool when asked to cool and is working intermittently...

I.e room temp 25C set temp 23C compressor will cycle on for 5 minutes then it will turn off and if yo go into the service menu the operation details in the controller comp Htz are at 0.0 when the compressor should be running... air offs are about 14C when compressor does run. 6 weeks ago monitoring device was placed at the airoutlet to monitor air offs over a 24hr period and unit was turned to 18C. Unit would never achieve 18C in this room anyway as it never really drops below 22C as unit is undersized for the room but when they got the data back the air off temps returned to ambient at various times through the night as if the unit was switched off. However it wouldnt have been possible to turn it off as the controller panel is locked in a cabinet in the room so could not be turned off. I was also on shift at the same time so know this wasnt possible for it to be turned off.

Seem to have to turn unit on and off a few times and then compressor will start.

Have checked the error logs in the service menu and E57 comes up which is for shortage of refrigerant. This error code must have been from a while ago too as the compressor run time is about 11775 hours and this error code was entered when compressor run time was at 10555 hours.

However this error code isnt flashing up on the controller and the indoor unit continues to run. Only way to see the error code is by accessing the service menu so this leads me to think that this error code is no longer valid.

How would you remove this error code from the controller? Does it have to powered on and off at the outdoor unit? Or do error codes always remain in the log?

I am confused as no error code is coming up when we turn the unit on and when you look at the controller all appears to be well.

We have had an engineer attend today but given past experience at work with our service engineers they dont do the work they are supposed to and most of the time do not check the controller or know how to check it.

Todays engineer was here 2 hours (I work nights so didnt have chance to see him) however the error code still shows up in the controller log.

Any ideas?

Thank you.

[Brian_UK]

Another good day at the office then?

You say that the unit has switched itself off, did it restart later or did it stay off?

Thinking... a shortage of refrigerant could cause a freeze protection stop, maybe it needs a set number of them before it triggers a fault code.

[back2space]

Another good day at the office then?

You say that the unit has switched itself off, did it restart later or did it stay off?

Thinking... a shortage of refrigerant could cause a freeze protection stop, maybe it needs a set number of them before it triggers a fault code.

Bad day at the office indeed haha... The service company have not been doing their jobs properly as many many of the chilled water fan coil units have had seized actuators or they were stuck in cooling and blocked strainers. Despite preventative maintenance the filters had not been cleaned on most units!

This split unit is used when the main system is off as its for a room that the night workers (me) occupy through the night. The main system is switched off over night and we use the split to cool/heat the room through the night until the morning when the main system takes over.

The indoor unit doesnt switch off just the outdoor unit, i.e compressor and fan stops despite there being a demand for cooling. Its noticeable as the temp starts to climb again and doesnt drop.

I am thinking that if there is a shortage of refrigerant then the outdoor unit could be tripping on low pressure cutout then coming back on later once its powered on and off again?

[back2space]

The room temp is reported by the controller as 24C set temp is 22C and the compressor is cutting out every few minutes and then comes back on again a little later.

[Gingerair]

Hi B2S

If you post what model unit you have it may give everyone a better idea of what it can self monitor & what faults it could display..

For example, the compressor could be overheating, cutting out on it's internal klixon but not showing as a fault.

Can you monitor running pressures & possibly suction & discharge temps...

The E57 fault could be an old one that was attended to at the time but not deleted from the fault history..

I think you should get a 2079 course & a set of gauges for christmas...

[back2space]

Hi B2S

If you post what model unit you have it may give everyone a better idea of what it can self monitor & what faults it could display..

For example, the compressor could be overheating, cutting out on it's internal klixon but not showing as a fault.

Can you monitor running pressures & possibly suction & discharge temps...

The E57 fault could be an old one that was attended to at the time but not deleted from the fault history..

I think you should get a 2079 course & a set of gauges for christmas...

Hi Gingerair

Thanks for your reply, I am unable to access the outdoor unit to take any readings as I dont have access to the roof. I am also not an engineer so I wouldnt be able to do it... I do agree though I should get a course and some gauges for xmas because I do actually want to resolve faults!

I have managed to have a look at the job sheet that the engineer has filled out when he has finished today. He has checked the flares inside and out and no leak could be found. He has then connected his gauges and checked running pressures and these were indicating a shortage of refrigerant so he has reccomended that a pressure/leak test is done... I guess we will be getting someone else out soon to do that.

I do agree the fault looks to have been there a long time as there has been compressor runtime since as the hours have gone up. Potentially it could be that no extra refrigerant was added to the pipe run when the unit was installed... I must admit I havent heard the drain pump run for ages... no wonder we are getting poor cooling.

ACcording to the fault codes list it states that while the fault is still the error code remains.

Think indoor is a FDUM50VD 5kw ducted inverter split running on R410 and the outdoor is a SRC50ZIX-S

[bigor_2]

It is bad that there is no access to outdoor unit.
No possibility to remove error from middle of alarm log.
If compressor will cycle on for 5 minutes then there should be a new error. Sooner or later

[back2space]

It is bad that there is no access to outdoor unit.
No possibility to remove error from middle of alarm log.
If compressor will cycle on for 5 minutes then there should be a new error. Sooner or later

I think its tripping out on low pressure.

Engineer has a confirmed it is short of refrigerant so it is cutting out on low pressure then when we restart the unit later it will give it another go sometimes it will run for a bit before cutting out... obviously outside temp will affect the pressures as well.

We are aware that until the unit is fixed and gas is refilled then the error will stay on the controller and once powered on and off at the outdoor unit it will clear the error if its rectified.

[Gingerair]

Sounds like you've got it covered

[back2space]

Sounds like you've got it covered

Yeh its getting the quote approved though!

[Gingerair]

Oh, the quote will probably be out of date by the time the authorisation comes through then