Mitsubishi Mr Slim Working

Assalam o Alaikum all,

I just bought Mitsubishi Mr. Slim (1.5 ton) a week ago.

I m just unable to understand its working. It has two green lights as Operation Indicators. What I've noticed is that no matter i set it to 31 deg-C or 20 deg-C, these lights keep glowing, meaning the unit is unable to reach to the set point temperature. Cooling seems to be okay, but i m unable to know if it trips in between or the compressor keeps running all the time. Therefore, right now, i manually switching it on and off, just to be on the safe side of consuming too much electricity.

Any comments ?

I have been using this AC for more than 2 years without any problem. One of the light does turn off after some time but since it is not happening in your case so may be it is actually not reaching that temperature. May be the room in which you are using is too big or has windows or something opened?

[quote=“akif, post:, topic:”]

Assalam o Alaikum all,I just bought Mitsubishi Mr. Slim (1.5 ton) a week ago.I m just unable to understand its working. It has two green lights as Operation Indicators. What I’ve noticed is that no matter i set it to 31 deg-C or 20 deg-C, these lights keep glowing, meaning the unit is unable to reach to the set point temperature. Cooling seems to be okay, but i m unable to know if it trips in between or the compressor keeps running all the time. Therefore, right now, i manually switching it on and off, just to be on the safe side of consuming too much electricity.Any comments ?

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Mitsubishi Mr. Slim A/C has two green LED indicators. One is power, it will remain ON until you turn off the unit by remote or by power switch.

The other LED is supposed to show compressor status but there is a catch in it. Suppose you set the temperature at 25C, the unit will start and both lights will turn ON. The compressor light will turn off when the unit has cooled the room down to 28C. You will think that AC has turned off after colling to set point but it still runs.

This information is described in the user manual. There is a 3 degree difference which I am unable to understand why they did so. May be this is hysteresis they build into the design.

Thanks for all the feedback.

This is not a big room; and there is no window even slightly open.

I tried a couple of things; like, started with 31 deg-C set point (Outside temperature ~ 36 deg-C; So i believe inside temp must be around 31-32). Both the lights kept ON. I checked it for about half an hour.

Then another time, I started it with 26 set point and kept for about 15 mins; both lights kept ON (outside temp was about 30). Then I raised the set point to 30; the light went off. Then I went out to see if the compressor fan is running; the compressor and the fan, both were off. Then I lowered the set point back to 26. The compressor took start after about 3 mins, but the other light kept OFF. After another 2-3 mins, the light again became ON and remained ON after that. I went to sleep after that and whenever i awake in between, i saw both lights ON.

Might be there some problem with the thermostat or its temperature sensor ?

Or may be I should try some other experiments with the temp set point!

Its time to read the manual first :) All this behaviour is documented by Mitsubishi.

@Ijaz

The manual i received with this product (MS-C18VC) has very limited info. Like about the operation indicator lamps it just says:

1) when both lights are on, the unit is operating to reach the set temp (about 2 deg-C or more away from set temp)

2) When one light is on, the room temperature is "approaching" the set temp (about 1 to 2 deg-C from set temp)

It does not tell if the compressor trips in case-2 or not.

I'm trying to search its manual on google too; if you or anyone else has a soft copy or has a link to it, kindly let me know.

Thanks.

P.S: How much current does it draw; mine is drawing above 8 Amps.

run it on "econo cool" mode and thats it :)

Yesterday, i again tested it and it occurred that compressor does not immediately trip with the second light turning OFF; it continues running for some while to reach the set temperature and then trip. Then it again takes start after 3 mins. My Mitsubishi Mr. Slim is unable to achieve even 26 deg-C. Perhaps the gas is low, or there might be some problem with its compressor. I am planning to contact the vendor tomorrow.

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I've also been using Mitsubishi MR. Slim (MS-C18VC) from last two years. It is one of the best of its kind.

In this case it obviously needs maintenance.

And i agree the manual is too short, doesn't provide enough details.

As i mentioned, it is brand new. Yesterday, I got it checked by the technician who installed it. He told that the gas pressure was alright (around 67) on the compressor suction side. He suggested that the outside temperature is too hot, thats why it is unable to achieve 27 deg-C.

what he is a joker or technician? my Samsung AC can easily down the temperature to 17 when its on Turbo mode (Outside temp 45c)

if you are in warranty then replace your AC or force them to fix it (I bought AC not Heater)

I would say get free maintainence before the time ends. Something is wrong with your unit for certain.

There is something wrong with the technician you called bro.

At what height your Unit is fixed? the recommended height is 7 feet, if your unit is fixed at 8 or 9 feet,it is very hard to trip even on 30 degrees.......from my personal experience.

And if your Outdoor Unit installed in under direct sunshine it can also effects temperature inside....

[quote=“armada, post:12, topic:14524”]

what he is a joker or technician? my Samsung AC can easily down the temperature to 17 when its on Turbo mode (Outside temp 45c)

if you are in warranty then replace your AC or force them to fix it (I bought AC not Heater)

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Is it 100 tons AC? Or room size is 01 cubic feet?

Unfortunately, this technician is one of the best we have here; he was recommended by the vendor himself. Perhaps I need to go to the vendor now to discuss the issue.

The technician also left some piping (1-2 foot from indoor unit side and 1 foot from the outdoor unit side end) without insulation, and told that it does not make much difference. May be I need to insulate it first before giving final verdict against the compressor.

Outdoor unit is NOT installed very high up; its base is around 6.5-7 feet from ground.

Maximum temp of our area was about 49 deg-C last week; but this max temp is at about 3 pm.

This room is about 11x12 feet and only half the length of one of its walls is exposed to direct sun; all the others are common walls with other rooms. However, the exposed wall has a 6 feet wide window also.

[quote=", post:17, topic:14524"]

Is it 100 tons AC? Or room size is 01 cubic feet?

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Room ceiling covered with foam tiles (inside)

it has other rooms in all directions with upper storey

it has no any skylights

AC cooling capasity is 24,000 BTU

[quote=“Ammar77, post:15, topic:14524”]

At what height your Unit is fixed? the recommended height is 7 feet, if your unit is fixed at 8 or 9 feet,it is very hard to trip even on 30 degrees…from my personal experience.

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Sorry, I asked you about indoor unit but forgot to mention…

Thanks.