View Full Version : Mitsubishi(s) Lock out in minutes

fridge doctor
19-06-2007, 09:22 AM

I have a few problems with some 3 year old Mitsi's and wondered if anyone had any views. Mitsubishi website isn't responding to me at the present time.


I found that for reasons which are best known to himself, my customer has been operating his 5 AC units via mechanical time clocks placed at power source for each unit. Although technically he is only reproducing a power cut situation - which his manual tells him will cause no prob, and settings will revert - In practice I feel that he is 'abusing' the system in preventing the proper start-up/shut-down sequencing during which time certain self diagnostic checks may well be performed by the unit(s).
Anyway, the fact is that he is having problems with 3 units now, and the fault is similar in that they start up (on the remote), run for an undetermined time (between 5 mins -24hrs) and then 'lock out' showing a series of flashing signals on the 'run' and 'timer' lights.. These fault codes vary slightly, but all have roots in 'failed compressor' ... which is clearly not the case.
Because of his 'mis-use' of the operating procedure, I naturally suspect the electronics on the boards, but I am reluctant to stick my neck out?

One of the units I looked at had in fact stopped working altogether when I got there. No response from the unit either switching on/off at the supply, or by remote. I decided that the IR receiving PCB must be at fault and in some sort of iinspired madness I turned the power off, froze the PCB components, turned back on and the unit responded immediately, correctly carrying out all remote instructions for the next minute or so until the board returned to room temp. Once set up (during the first minute) the unit happily ran on, and up to an hour ago still was. Obviously not a cure, but effectively proved the point that the IR board must be faulty.
Does anyone have any ideas about this please ?

Also : Need a copy of user instructions for Mitsi FDKNA251 (Only need how to set internal timer page) Many thanks