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back2space
02-06-2011, 02:56 AM
Hello all

The unit is not working properly again at my work - This was regassed at the end of last year and was very costly to do so, however the compressor appears to keep cutting in and out.

Controller is a RC-E3 wired remote. The indoor unit is an FDUM Ducted - not sure of the capacity though.

Having checked the fault codes it is still showing E57 in the fault menus which suggests low gas issue… so either this wasn’t rectified properly last time or there is a problem with the unit thinking it is low on gas.

The room temp is 25C and stuffy, the set point is 22C so there is a demand for cooling & the compressor should be running but the room is getting warmer. Accessing the service menu on the controller (check & set buttons pressed one after another and held) and navigating to "comp hertz" it appears the compressor is short cycling between on and off frequently.

This could be because it is low on gas again and with the outside ambient higher this is a safety mechanism to protect the compressor from overheating. The problem appears to be worse when set to high fan speed as there will be more heat transfer taking place between the refrigerant and the internal air.

When it was regassed it was working really well but the air in the room feels very stuffy so I suspect short of gas again - there is no flashing error code on the display and you have to nagivate to the faults codes list in the menu to see the fault code.
E57 can be seen here http://www.3dair.co.uk/DOWNLOADS_may07/Error%20codes/ErrorCodes%20-%20R410A.pdf (http://www.3dair.co.uk/DOWNLOADS_may07/Error%20codes/ErrorCodes%20-%20R410A.pdf) so I suspect this has never been fully rectified as surely the fault code should clear from the controller when rectified. When looking up E57 on the link above it says the light on the controller should be flashing and the indoor unit would be off - neither of these occur and first looks at the controller suggest all is normal.

I've reffered this back to our FM on site as this needs investigating. I think if the unit was short on gas then it should not be running at all as the above link suggests but the strange thing is that it has been running fine the last few months but as soon as it is warmer outside tonight (15C) we are having problems with it.

Any help greatfully received.

Iceman1956
02-06-2011, 02:12 PM
I would first start by recovering the refrigerant. Check the weight you have recovered against the correct charge for the system. If the installed pipe length is below the manufacturers stated length, then the correct charge will be on the plate. If you have lost refrigerant carry out full Nitrogen PLT, to find and repair the leak. only then should you recharge with the correct refrigerant amount.
E57 is insufficient Refrigerant, so I would suspect you still have a leak.

Chris Goven @ HRP Rougham is a good contact if you need Technical Help with faults.

As for stuffy air, Air Conditioning will not make this any better, look at introducing some fresh air to the room.

Brian_UK
02-06-2011, 11:28 PM
Are the filters clean ?

Iceman1956
05-06-2011, 04:10 PM
Are the filters clean ?

I always forget to ask the obvious. as it's the first thing you would expect to be checked.

monkey spanners
05-06-2011, 07:15 PM
Don't know with mitsi stuff, but some units won't neccessarily throw a fault code on the controller but will have a load of blinky leds indicating some fault or other on an outdoor board.

Sounds like it wants looking at before any damage is done anyway.

Jon :)