Mitsubishi mr slim temp not going down.

[quark555]

I have Mitsubishi mr slim, and the temp is not reaching less than 24C. note that I'm living in UAE, and temp. outside is around 35C.

Initially I was having P8 error, and technichian replaced the refregirant pipes to fix the issue. and one more thing; all compressors of different appartments are all installed in one floor (technical floor) and it's temp is really high.

Help me plz. I need to get my 20C back.

[Brian_UK]

Did the technician recharge the unit correctly after the repairs ?

I'm not sure why your man replaced refrigerant pipes for a P8 fault which is referring to an electrical problem - <confused>

[back2space]

It also sounds like you need to increase ventilation in the technical room as units will end up over working due to the high temperature.

[quark555]

as per him, yes he did..

[multisync]

Did the technician recharge the unit correctly after the repairs ?

I'm not sure why your man replaced refrigerant pipes for a P8 fault which is referring to an electrical problem - <confused>

P8 is just outdoor unit fault. SOG being one of the many

TROUBLESHOOTING TIPS / P8 ERROR CODE

These systems have very sophisticated microprocessor control systems to operate the
system efficiently and to protect it from conditions which could lead to damage.
If the P8 Error Code appears on the wall controller this indicates a problem with the
condensing (outdoor) unit. There are several possible causes for this fault. A few are
mentioned in the literature provided by Mitsubishi, but experience has shown that
many other conditions can also result in the P8 Error Code.
1. Is there power to the outdoor unit? P-series indoor and outdoor units are
typically wired from separate sources. On cooling only units the indoor section
is 120/1/60 volt and the outdoor section is 208-230/1/60 volt. On heat pumps
both sections are 208-230/1/60 volt. The indoor unit could have power to it but
not the outdoor unit, resulting in a P8 fault.
2. Is the 2-wire 12 VDC communication link between the indoor unit and outdoor
unit intact? This wiring is polarity sensitive so if the wires are crossed, shorted
or broken this is also a problem to look for. Ensure the wires are secure in the
terminals as well. Loose wiring can cause intermittent problems.
3. There is a 208 Volt jumper for the outdoor unit control board. Verify your
power supply voltage and insure this jumper is correct for what you actually
measure at the unit with your meter. The outdoor board monitors the power.
4. The outdoor board monitors the temperature of the refrigerant leaving the
condenser coil and modulates it’s condenser fan(s) to try and maintain a 95°F
temperature. If the discharge temperature gets too high, or too low, the unit
will shut off. Verify that the pipe temperature thermistor is not open or
shorted, and that it is snug in the well attached to the refrigerant pipe.
5. Is the condenser fan operating? On the extra low ambient models (-40°F) there
is a control to disable the condenser fan(s) during very cold weather. If this
control is defective it may be preventing operation of the fan(s) in warm
weather. Ensure the condenser fan is ramping up to full speed when required.
6. Is the unit operating year-round but not a -40°F low ambient design? You can
determine this easily because the accumulator on -40°F units is heated and
insulated. Ensure the accumulator heater is functioning in the winter.
7. Is the system undercharged, or overcharged? It is a capillary tube metering
device so the refrigerant charge is critical. P-series units have an accumulator
which enables it to store enough refrigerant for up to a 100’ line set. After 100’

additional refrigerant must be weighed in based on the total 1-way lineset

[quark555]

P8 is just outdoor unit fault. SOG being one of the many

Thank you very much for your reply. This what happens when you have bad maintenance service at your buidling... (No trained staff, no supervisor to care, ...).

Regarding the power, I don't believe that there is any problem with it.. since that no signs of power failure.. the only thing was happening.. (Compressor stops working, and F8 was shown).

Data cable, also I don't think that there was any problem.

I'm not really sure if the problem was due to having a large number of compressors in the same place, with really very bad ventilation. (I'm not Mechanical Engineer, -i am electronics engineer - but with my AC now, and after reading all about it, I think I could understand many about it...

I'll make them check all your points, and once again, thanks a ton for your reply.

[back2space]

I think the issue is with poor airflow in the area where the condensers are.

This will cause the unit to shut down as it is operating outside design standards.

[quark555]

Thank you all for your answers.. the problem is still there.. and those maintenance people are just careless.. I think the only solution would moving shifting only from this place...

[back2space]

Thank you all for your answers.. the problem is still there.. and those maintenance people are just careless.. I think the only solution would moving shifting only from this place...

Is the problem still there if you shut down all the other units and only run one of the units so that there is less heat in the space where the condenser units are?

[quark555]

The problem is still there. The other units belong to other flats.. so I can't really do it.. (Honesly I got upset a few moments ago and I thought I was supposed to do that!!)...

[quark555]

Imagine more than 40 units in the same place!! in the middle of the 25 floor building (13th floor). No exhaust no ventilation.. and no insulation; thus my floor is really like oven... That who designed this should be punished badly...

[back2space]

Imagine more than 40 units in the same place!! in the middle of the 25 floor building (13th floor). No exhaust no ventilation.. and no insulation; thus my floor is really like oven... That who designed this should be punished badly...

So theres no ventilation at all? No louvres or ventilation to the outside etc?

You will be able to turn units off to the other apartments by turning the isolators off at the condenser units, you dont need access to the flats to do this. I would try this then you have your proof that its overheating.

You need to report this to the apartment management as otherwise they are going to have very expensive repair bill when condensers start going down.

Can you perhaps upload any pictures for us to see?

There is no doubt that the fact this room is not ventilated is the cause of the problem. In the winter this room will be like a freezer.

[quark555]

I have already reported this issue, but those people are so lazy...
You can feel the temperature over there.... I'll try to get a photo tomorrow.

[back2space]

I have already reported this issue, but those people are so lazy...
You can feel the temperature over there.... I'll try to get a photo tomorrow.

Then you need to keep on at them, keep phoning every day until they rectify it.

How do you have access to this area? Is it not locked for residents? Or are you an engineer?

YOu need to do more than report the issue, you need to tell them regarding the danger and that they will burn compressors out, costing tens of thousands of $$$

[quark555]

I am living in this building.. How I get there?? The door is opened!!..(so u can imagine how careful they are)
I've been phoning all the time, and blasting sometimes... but really don;t know what to say...

[back2space]

I am living in this building.. How I get there?? The door is opened!!..(so u can imagine how careful they are)
I've been phoning all the time, and blasting sometimes... but really don;t know what to say...

Well maybe rather than getting angry with them say that the systems are tripping out and that you have had an engineer who says that the whole lot is going to do major damage.

[Makeit go Right]

How I get there?? The door is opened!!

Maybe try leaving that door open for a while and see if it gets some airflow through that condenser room.