Results 1 to 11 of 11
  1. #1
    Join Date
    Feb 2008
    Posts
    6

    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

  2. #2
    Join Date
    Jan 2008
    Location
    melbourne aus
    Posts
    80

    mr slim

    hey trapper, do you have a code book?
    if not you may be able to down load one of internet,

  3. #3
    Join Date
    Jun 2001
    Location
    Greater Philadelphia Area
    Posts
    124

    Similar trouble...

    Quote Originally Posted by trapper View Post
    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
    Did you figure it out?
    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.
    Any input?

  4. #4
    Join Date
    Dec 2007
    Posts
    89
    read ur manual, u will be surprised how helpful the guide is

  5. #5
    Join Date
    Jun 2008
    Location
    va
    Posts
    800
    Locked up compressor or bad capacitor, assuming the voltage is not low.

  6. #6

    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

  7. #7
    Join Date
    Jun 2001
    Location
    Greater Philadelphia Area
    Posts
    124

    Hmm Uhhh

    Quote Originally Posted by Mrfixit39 View Post
    read ur manual, u will be surprised how helpful the guide is
    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.
    But anyway...
    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.
    Thanks Guys

  8. #8
    Join Date
    Feb 2008
    Posts
    6
    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

  9. #9
    Join Date
    Jun 2001
    Location
    Greater Philadelphia Area
    Posts
    124

    Thumbs up No Problemo...

    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.
    Thanks again.

  10. #10
    Join Date
    Feb 2008
    Posts
    6
    good luck, let me know

  11. #11
    Join Date
    Jun 2008
    Location
    LONDON
    Posts
    57

    Mitsubishi

    Quote Originally Posted by Wethead View Post
    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.
    But anyway...
    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.
    Thanks Guys


    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.

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