mitsubishi mr slim problem
i'm not to familer with this unit dont start, contacter pulls in i get 41 amps then she goes off on p7(overheat) gauges read 95 low,100 high when comp is off, i would automaticly say replace comp, but i was told these units have some other components that may be holding it out??? any suggest. thanks guys
hey trapper, do you have a code book?
if not you may be able to down load one of internet,
Did you figure it out?
Originally Posted by trapper
I'm having the same problem, except I get no fault codes because system breaker is tripping.
Problem started out as occasional nuisance and became more frequent until now.
Everything tested fine, amp draw, windings, capacitors, voltage, temps and pressures. (well... ohms a tad high on windings. Specs call for max of 2.1 on start- I got 2.5 Specs call for max of .9 on run- I got 1.1)
Unit never failed during a service call until today...
Windings and cap test the same but compressor hums for 2 seconds and goes quiet... amp draw goes to 53 amps for 5 seconds until breaker trips.
I'm determing this to mean I'm looking at a bad compressor but I wanted to make sure I'm not missing something.
read ur manual, u will be surprised how helpful the guide is
Locked up compressor or bad capacitor, assuming the voltage is not low.
what mod. & how old
if this is a new inverter model then don't jump the gun with replacing compressor, get diagnostic specs. from mitsubishi. if its an older mod. without the new inverter compressor then yea its probably a bad commpressor
I'm not sure why you're assuming I'm not reading the manual since I mentioned the motor ohm specs which aren't given on equipment data plate.
Originally Posted by Mrfixit39
The unit is MU-24WN... the service manual is extremely helpful.
The compressor is not inverter type. (thank you MSAIR) I haven't had the oppurtunity to work with inverter type yet but my understanding is that they are rectifier controlled DC variable speed motors correct?
No voltage problems. Cap tested fine as did everything else except for the slightly high resistance on the windings I mentioned earlier.
After 3 min delay on power up, control board powers condenser fan just a few seconds before it closes compressor contactor. Everything is peachy until contactor closes.
Sooooo... I disconnected compressor common to isolate the compressor from system and everything stays on fine with total amp draw from the condenser and evap fan reading perfectly (indoor unit receives power from condenser unit)
No fault codes to go by since system breaker trips.
I'm quite certain I'm looking at a locked compressor.
I was curious what Trapper found to be the problem with his and I wanted to be sure I might not be missing something.
Interesting txv Mitsubishi uses on that system. I never came across that before. Anyone familiar with Mr. Slim models know if that type is being used anywhere else? TXV is located in the condenser unit (therefore entire lineset is insulated) and is controlled electrically thru the board using thermistor sensor.
hey guy, sorry i took so long, my laptop had a virus-lost everything anyway i started to reclaim my gas-i pulled out maybe 2lbs, before i said let me try a booster on my capacitor, dame that boy started right up, all i did was charge it back to proper amps shes running great- (i had replaced the cap prior to this ? but the booster did it
Thanks for the reply...
I thought about putting a hard start kit on it just to see what it does.
The problem started out as occasional and increased over a year and a half or so until now that it is locked.
Maybe I'll try it quick before the replacement compressor comes in...
I'll let you know what happens.
good luck, let me know
Originally Posted by Wethead
We are Mitsi and Daikin specialists.What you describe is probably faulty 4 way valve.One more thing is the power supply protected by r.c.d. (residual current).If yes please disconnect it and rewire to simple Live ,Neutral,Earth.
Wish you luck.Got lots of info about Mitsi, Daikn if you need something PM me.