20 Most Recent Mitsubishi MS12TN Air Conditioner Questions & Answers

Push the reset button of your remote control and try. If it wont work try to "off" and "on" the circuit breaker to reset the unit and try the remote control.


Mitsubishi... | Answered on Oct 27, 2017

I am experiencing a similar problem with my Mitsubishi slimline MSH09TW unit; about 4 years old; It use to give us very hot air now it is giving some what hot air; northeastern USA current temperature about 15F. You think frigid weather in Cranbury NJ could be responsible or some thing else is going on. Please help me if you have some time and knowledge about Mitsubishi heat pumps. Sincerely, DSS

Mitsubishi... | Answered on Nov 20, 2014

Malfunction of drain pump. Check drain line hose. If fully dusted, clean it. If drain pump mechanism locked, replace it. Thanks.

Mitsubishi... | Answered on Feb 18, 2011

Here is where you can find all the info you will ever need about Mitsubishi Air Conditioning units...
Check out this tip that I wrote about that...

Mitsubishi Air Conditioner Troubleshooting and Repair


Mitsubishi... | Answered on Feb 08, 2011

E-6 Indoor unit heat exchanger sensor [ThIR] defective (resistance is open circuit or closed circuit).
• Poor connection of sensor connector on the indoor PCB.Rectify.

Mitsubishi... | Answered on Jan 01, 2011

It could be a couple of things...

There could be a problem with the main control board in the outdoor condenser...it does not tell the solenoid valve to open to feed that unit...

Or more likely the solenoid valve it's self is bad and is not opening....
To find the problem the voltage would have to be checked to see what the problem is exactly...

Then the whole unit will have to be pumped down the valve replaced and then the unit vacuumed and recharged...

here is a tip that I wrote about Mitsubishi units also...

Mitsubishi Air Conditioner Troubleshooting and Repair


Mitsubishi... | Answered on Nov 18, 2010

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Here is a tip about Mitsubishi Air Conditioners and how to get the manuals for all of the Mitsubishi line. The manual include both troubleshooting and installation.

Mitsubishi Air Conditioner Troubleshooting and Repair


Mitsubishi... | Answered on Sep 14, 2010

DO NOT ADD CHEMICALS TO IT ANYMORE! Have a qualified technician carefully check for leaks with a halogen detector such as the H10 or equivelant.

Mitsubishi... | Answered on May 27, 2010

There is a red reset on the outdoor unit, near where the copper lines connect to it, also there should be fuses in the disconnect box, near the outdoor unit, that the electrician installed.

Mitsubishi... | Answered on Apr 04, 2010

There is small PCB in the AC, this PCB is malfuctioning also there is automatic ON /OFF switch Check whether ti is working properly or not.

Mitsubishi... | Answered on Oct 02, 2009

Hi, you'll need to double check refrigerant (freon) charge. working for a day or two, could means there's refrigerant (freon) leak, if there's no leak and refrigerant (freon) charge is o/k, check your electrical, you didn't say what make or model is your a/c, check condensing unit (outside) or evaporator (inside) for solenoid valve it's normally located on freon lines inside of evaporator or condensing unit (outside) check for loose electrical connections, if all (3) don't work, could be freon leak, or compressor not working/running. check compressor and capacitor. make sure compressor is working/running. if it's just one that's not working, then it could be electrical problem with that evaporator that's not working, there's a solenoid valve, that controls flow of refrigerant/freon to evaporator, when you set your thermostat to desired temperature, that's the device that controls flow of refrigerant/ freon to evaporator, it could be in evaporator or condensing unit, or on refrigerant lines, double check, with more info,make/model i could be more accurate. also check your thermostat or senser in unit inside/evaporator. good/ luck.

Mitsubishi... | Answered on Aug 25, 2009

Heya Harmlhs,
If the system is going into a vaccum that shows the compressor is working I would say it is either short of gas or it is a problem with the RCD. If the compressor is getting really hot i would say that it would short of gas and it is not best to use it untill a licenced person comes and looks at it before the compressor is seriously damaged.

Mitsubishi... | Answered on Apr 04, 2009

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