Mitsubishi Mr Slim a/c problem

[Claude Paradis]

Hi,
I have a Mitsubishi Mr Slim 12,000btu model MSH-12DN for 10 years.
I never had any problem up until now. When I start the air conditioning
it seems to work for less than 5 minutes and then the fan simply
recirculate the inhouse air. Everything seems normal, as far as the
indoor fan and the outdoor unit.

I opened the indoor unit and checked the room temperature thermistor and
the defrost thermistor and they respectively read 10.7K and 6.4K.

Does anyone would know what could be the problem or what should I check
next to determine what could be the problem?

Many thanks,
Claude

[richard bartlett]

hi claude

below

"Claude Paradis" <cpar...@sympatico.ca> wrote in message
news:3D5F20CE...@sympatico.ca...

> Hi,
> I have a Mitsubishi Mr Slim 12,000btu model MSH-12DN for 10 years.
> I never had any problem up until now. When I start the air conditioning
> it seems to work for less than 5 minutes and then the fan simply
> recirculate the inhouse air. Everything seems normal, as far as the
> indoor fan and the outdoor unit.
>
> I opened the indoor unit and checked the room temperature thermistor and
> the defrost thermistor and they respectively read 10.7K and 6.4K.

are you measuring resistance?

if so this is only relavent to a corresponding temperature as they should
checked against a temperature chart

however i suspect that the 'defrost' sensor is not sensing a temperature
change on the evaparator and after a set period -say five minutes- and
switches off the compressor.

this is an inbuilt safety device which indicates several possibilities but
the first thing would be to check the refrigerant charge....

look for a slight glistening around the copperpipe connectors (brass nuts)
on the outdoor unit and see if it's oil

cheers

richard

[Claude Paradis]

Hi Richard,
As far you know, is there a way to really prove that it is
the sensor, either by short circuiting the plug or make it open? This way
then, I will go and simply replace the defrost thermistor.

In the mean time, I will check the outdoor unit for linkage.

Many thanks,
Claude

richard bartlett a écrit :

[richard bartlett]

i don't see why you should suspect the sensor...

as mentioned they operate by a varying resistance so removing/shorting will
just fool the circuit board to think it really is faulty..

by the fact that the resistance is very close (they probably shouldn't be
the same anyway) means they are okay..

personally i don't suspect there's anything wrong with the sensors...

i mention the outdoor unit for leaks as this is the one real suspect point
of japanese systems ie flare connectors which due to the fact that the nuts
are constantly changing temperature can -and often do- work loose enough to
release the refrigerant charge (luckily the indoor connectors don't seem to
suffer the same problem to anywhere the same degree)

sitting here i suspect refrigerant leakage BUT i am rather a long way away!!

cheers

richard

"Claude Paradis" <cpar...@sympatico.ca> wrote in message

news:3D5FA931...@sympatico.ca...

[richard bartlett]

i don't see why you should suspect the sensor...

as mentioned they operate by a varying resistance so removing/shorting will
just fool the circuit board to think it really is faulty..

by the fact that the resistance is very close (they probably shouldn't be
the same anyway) means they are okay..

personally i don't suspect there's anything wrong with the sensors...

i mention the outdoor unit for leaks as this is the one real suspect point
of japanese systems ie flare connectors which due to the fact that the nuts
are constantly changing temperature can -and often do- work loose enough to
release the refrigerant charge (luckily the indoor connectors don't seem to
suffer the same problem to anywhere the same degree)

sitting here i suspect refrigerant leakage BUT i am rather a long way away!!

cheers

richard

"Claude Paradis" <cpar...@sympatico.ca> wrote in message

news:3D5FA931...@sympatico.ca...

[Stormin Mormon]

Wow, it sounds as if you got your money worth out of that one.
How about call a techie and aske for a clean and check? With
emphasis on clean.

Sounds like it's got an inefficient condensor, and it is having a
bad time with the heat transfer. Probably cycling off on
thermal.

--

Christopher A. Young
Learn more about Jesus
www.lds.org
www.mormons.org

"Claude Paradis" <cpar...@sympatico.ca> wrote in message
news:3D5F20CE...@sympatico.ca...