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Ihave a pk36fk3 indoor unit &a pu36ek outdoor the proplem i have is the unit is running but i can not control from stat and the stat shows EO THIS IS A NEW STAT A PC/PK G13-N070112V THE OLD STAT SHOWED A BLAINK SCREEN

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Check for a short in the tstat wire sounds like you have a short in th wiring

Posted on Sep 08, 2010


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My LG split Ac is running some times but some times not working and showing error code CH09

Split = Outdoor unit fan problem. Check Outdoor fan motor is plugged in, Electrically & Mechanically sound, if not replace motor, otherwise replace PCB.
Multi V= Indoor unit EEPROM error - Replace the indoor unit PCB, and then make sure to do Auto addressing and input the address of central control.

Jun 06, 2015 | LG Heating & Cooling

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Error message U4

Signal transmission error. Indoor and outdoor PCB's cannot communicate. Usually a faulty controller board in the outdoor unit. If the indoor unit otherwise functions normally (can control fan speed, louvres, beeps in replay to all remote buttons) then it is probably OK so check outdoor controller PCB.

Jul 21, 2014 | Daikin Mini Split Concealed Duct Units

1 Answer

I have a Rheem Furnace Model # RGPH-07EAMGR Serial # FD5D307F16000271. The unit keeps blowing the 3 amp fuse on the ciruit board. I verified the amp draw from the blower motor and it is well below the...

Hi, this fuse is for your 24volt controls, which means anything that runs on or is controlled by 24 volts. Check the thermostat wires at the board where they come in, as I have seen them skin the insulation and ground out blowing this fuse. The contactor coil on the outdoor unit is 24 volts and may be shorted. Its a matter of looking at all of the low voltage wires to the indoor and out door unit. If you have a dog, I have seen where they chew the wires causing a short, or from the sun causing the insulation to come off and short.Something is for sure causing a dead short on the control side, It would not be the stat unless you have been into the wiring behind it and maybe the R, red is touching. (9 times out of 10, a low voltage wire is touching metal or another wire, common. If all of the wires look good, you will need to do the process of elimination. Go to the outdoor unit, and the wires coming outside from indoors, if its a gas furnace, you will have 2 wires. Take them loose, and this will take it out of the circuit. Now try another fuse. If it holds, your problem will be in the outdoor unit. It would have to be the contactor coil. It has 2 small wires, one on each side. Pull them off, tape them so they dont touch and wire the 2 wires coming out back up. When you restore power to the outdoor unit, if it holds you will know its the contactor, it has points on it and this is what closes to start the fan and compressor, just 24 volt coil. This is not a high voltage problem, only a low voltage, so checking the amp draw on motors are wasting your time. After you eliminate the outdoor unit, take each wire off of the terminal block at the indoor unit. Write down how they go back!! This eliminates the stat wire and thermostat. If the fuse holds, you problem is in the stat wire touching in the wall, or at the stat. Most contractors will have an extra wire that can be used. You will need to ohm out the wires to see which is touching. Last thing to do, is kill all power, and remove the 4 screws on the board. It will have stand off's on it to keep the back from touching metal. Look at the back to see if it is burned any where on the raceways. If so, you have a shorted board. Please follow all of my steps and you will find this short. It is really very easy, now that you know its the low voltage side blowing the 5 amp plug in fuse. Process of eliminated the parts like the outdoor unit, thermostat by taking off the wires at the indoor unit and so on. You will find it. Please let me know and rate me on my help to you.
A/C, & Heating Contractor & Tech.

Jun 14, 2011 | Heating & Cooling

1 Answer

Eo error code indoor unit runs 2-3 seconds then gives eo error code problem started when mr chipmunk chewed mr slims 12 volt wire connecting to out door unit and shorted it . Outdoor unit has bad control...

You need a professional here. Once this has been repaired, I would suggest running the wiring to the outdoor unit inside some sort of piping to protect it.

Jul 20, 2010 | Mitsubishi Mr. Slim MXZ30TN Air...

1 Answer

A/C will not shut off

Hi, the photo is showing a split system, indoor unit and outdoor unit. Is it just the blower fan inside that keeps running, or the entire a/c keeps going? Lets say its everything. I would start at the thermostat and remove the cover to expose the control wires. Find the R terminal,Red wire and use a small screw driver to remove it from the terminal. If the unit shuts off, the thermostat contacts are faulty and you will need to replace the stat. Even though its only low voltage, 24 volts, I would shut off power when you take the wire off. If your stat is not a digital, you will need to remove cover and lossen several screws to remove the stat to get to the subbase and wires. On a digital you don't have to. After removing wire, turn on power to see what happens. If it keeps going, you have a thermostat wiring problem either at the indoor unit where the thermostat wires come in and connect or at the outdoor unit where they connect touching together somewhere. The red and green or red and yellow conductor wires have a bare spot and are calling for cooling all the time. You will have to look for this, it can be very difficult to find unless you can ohm out the wires. If its only the indoor fan running and not the outdoor unit, it still could be the stat, or you have a fan relay that is stuck. If you remove the panel on the indoor unit and look at the wiring diagram, don't let it confuse you, look for this, IDF and follow the wire or wire to FR fan relay. Depending on what type, you can try tapping on it with the but of the screw driver carfully, to see if that may shut it off. If not you will need to go to a a/c parts house or a appliance parts house to find one. Draw a good diagram so you know how to hook the wires back up, or you can get into more of a bind. Its worth doing this then trying to remember. Do these things and keep me posted on this. By removing the R, red wire at the stat will kill power to the fan if the stat is the problem, so you don't have to remove the G, green wire for fan, only the red. I will wait to hear back from you.
Best of luck,

Jun 06, 2010 | Ruud UBHC Air Conditioner

1 Answer

Outside unit wont go on ( central air conditioner)

Hi, yes when you hold down the contactor with a screw driver it will send high voltage to the unit and start up. What is happening is, on the lower sides of the contactor will be a 24volt coil, a wire to each side. You are not getting voltage to this coil for it to close the contactor on its own. If this system is central air with gas heat, you will have 2- small thermostat wires that tie to the 2- wires on the contactor coil. If its not gas fired, it will be a heat-pump with several wires coming from the indoor unit and thermostat. Either way, the 2 wires you need to worry about is the red and white or red and yellow for cooling coming out and connecting to the coil of the contactor, probably a blue and brown wire to each side. These are what closes the contacts on this. By using your finger it tells me you have high voltage there, that's good. If the indoor unit is running, the problem is either in the thermostat or the wires that come back from the outdoor unit to the indoor unit are not getting 24 volts. So, if the indoor unit runs, that tells me the transformer is good. Check the thermostat wire at the outdoor unit real well to see if it may have a break in the wires. If it looks good, go to the indoor unit and remove the control panel. There may be a panel switch on it that kills power to the indoor unit when removed and you may need to tape it down while you check things out. Just have it running when you pull the panel and if all stops, you will no.If it has a circuit board, look for a auto type plug in fuse 3 to 5 amp that may have blown. If you had a meter you could check the terminals at the 2 wires that head outside to start the unit for 24volts. If all looks good there, no broken or loose wires, go to the thermostat and remove the cover to expose the wiring. If its not a heat-pump and gas fired, you will have these terminals, RC, RH, with a red jumper wire across them, a G green for fan, Y yellow for cooling and a W white for heat.To see if the thermostat is to blame, take a piece of insulated wire and touch and hold it to either of the Red terminals and the yellow terminal. Have someone outside to watch the outdoor unit. If the stat is at fault, the contactor will close on its own when you jump the 2 terminals out. Make sure the indoor panel is in place first. I am almost certain this will be your problem since the indoor unit runs. If its a heat-pump, you will have more terminals at the stat. Still jump across the Red which is 24 volts to Yellow which is cooling. If the outdoor unit starts, replace the stat! This will solve the problem. Its just a matter of finding why and where you have lost the 24volt control voltage to the contactor coil to energize it, pretty easy if you follow my steps. It has to either be a broken thermostat wire at the indoor/outdoor/ or thermostat, or thermostat is faulty not closing R to Y to bring on the outdoor unit. Please keep me posted as I would like to know the out come. I am confident you can find the problem now that you know it is a 24 volt control problem not energizing the contactor coil. I will be waiting to hear back from you.

Jun 03, 2010 | Heating & Cooling

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I have a colman evcon split unit, I had a guy replace the thermostat (old electronic, new mercury) and everthing worked fine. One week later out side unit stopped and was frosted over on the outside. I can...

Hi, you do have a dead short in the control side of the system. Good that you bought a transformer with the breaker. Most people don't and will smoke several of them. Anyway, it is a split system. If it was iced up, it must be a heat-pump, not gas fired. The problem will be in either the stat wiring from stat to indoor unit, to outdoor unit, and if a wire is not grounded in the stat wires, one of the 24volt controls have a dead short as the breaker trips instantly. Here is what you will need to do. You will need to do a process of elimination on all of the 24volt controls. I would start at the outdoor unit as you engaged the contactor by finger to check for power. If you see no stat wiring outside touching, the coil on the contactor is 24 volts and may be the shorted control. Coil could be bad. Pull a wire off the coil,there will be 2 wires at the sides. I am sure you know which are the low voltage controls if you can replace a transformer, this is great. You can find this pretty easy. If you pull a wire off one side and reset the unit and the breaker does not trip, then you know the low voltage coil is compromised. If it trips, go to the next low voltage control as the 24 volt coil on the rsv ( reversing valve ) and unplug it. If you have the schematic handy, it will show you all of the componants on the low voltage side/secondary side of unit that you will need to check until the breaker stops tripping. This is the best way to find the culprit!! I have done this for 33 years as a contractor and I am sure you will find this short very soon by doing this. Here is a tip for you also. Sometimes on the transformers that have these tiny resets on them, will wear out pretty fast. What you can do is take a 3 to 5 amp automotive type fuse and on the 24 volt side of the transformer you just cut the red/ hot wire/24v. and crimp a female stak-on to each end of the wire you cut. Then plug each end onto the fuse.Use some electrical tape around it so any bare metal that may be showing will not touch and blow fuse. This is a good way to protect all transformers that have no breaker if you end up with a short. Cheaper to replace a fuse then to keep replacing transformers every time! The fuse will just blow and you can start looking for the short. Now on your unit you can go to the indoor section where the transformer is that you put in. You can eliminate the thermostat and control wiring to the indoor unit and outdoor unit real fast so you know where or which section the short is in. Just kill main power, now where your stat wiring terminates you will disconnect from the control board. Since you have a heat pump you will have more control wires to work with, so either draw a diagram or use the one on your panel to reattach. Remove the wires from the board that take off to the stat first and supply power back to it. If the breaker holds, you will know the short is either the stat wiring from the indoor unit are touching somewhere/grounded or at the stat.You will then know that's where the short is as you have narrowed your search way down. If it trips, you will do the same to the control wires that go to the outdoor unit. If you disconnect it at the board and it holds, you will know it is from the wiring there to the outdoor unit! So, you either have wires grounded from there out or a low voltage control part has burned out. If you remove all of the control/thermostat wires at the board to the indoor and outdoor unit and it still trips, the short will be in the indoor unit which will more then likely be the board itself. Yes sir, this is really a very easy fix for you and I feel you have the ability to do this checks your self. The short has to be on the low voltage side of the transformer as you have proved that! You traced it right back to the transformer secondary low voltage side. So, just take your time and follow my instructions the best you can, and you will find out which part of the system the short is in and then narrow the search down further! I have a hunch the coil is burned/shorted on the contactor :) A place to start by pulling one little wire off the coil. I know this is a long explanation but I wanted you to understand and help you as much as possible on how to tackle this. Sounds difficult but it is not at all. It is either a low volt componant on the outdoor/indoor/ thermostat/ or stat wiring. If none of those, with all low voltage wires removed at board and it still trips, the board is shorted to ground. You can kill power to indoor unit and carefully take the board loose to look at the back side for any hot spots and you will know its the board. I had one totally smoked on a 5 ton package heat pump yesterday in fact!!! I could not see it until I pulled the board/defrost board out far enough to see it, but I knew it was the problem as it would not control the reversing valve, fan control, or run the condenser fan motor. Please drop me a line and let me know how you are doing, please. I would love to know that you were able to find it as I know you will. Best of luck to you.

May 06, 2010 | Heating & Cooling

1 Answer

Indoor unit freezing up


Mar 09, 2010 | Heating & Cooling

2 Answers

Trying to wire RUUD gas furnace. connection block

No problem have done this many times. R from the t-stat goes to R on the indoor unit. G goes to G Y goes to Y and C goes to C if you have a C or the t-stat the you are using. If there is no C there dont worry about it. It only need to be hookup if the t-stat uses power from the unit to run. Many t-stats today use battery power and do not need the C wire hooked up. Now R and C from the outdoor unit. R goes to the Y on the indoor unit and C goes to C on the indoor unit. That means that you may have two wires under the Y terminal and sometimes under the C terminal on the indoor unit. If on the outdoor unit there is no designation of R and C dont worry, just hook one wire to each of the two wires there for your low voltage connection. It does not matter which one goes to which unless they are marked then it may matter.
This should get you up and running and see it really isn't that hard!! :-)

Nov 14, 2009 | Ruud UBHC Air Conditioner

1 Answer

Breaker keeps getting flipped off

20kw heat should have 2 separate 60 amp circuits on number 6 wire.

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