Another Aircon Question

[jbrain]

I have two identical aircons Daikin 12000 Btu inverter installed in 2 bedrooms, where room 2 is only used during the weekends.

When I set the remote to 26 degrees and the fan on automatic, de room temperature in both rooms in the morning would be 26 degrees checked with digital thermometer.

Then after almost a year I would notice that in room 2, the temperature would reach only 27.5 to 28 degrees, so I started checking.

I insert the thermometer sensor inside the blower unit and set both to maximum cooling capacity which is 18 degrees.

Room 1 will register a temperature of 9 degrees straight at the exit of the indoor unit, while room 2 will be even slightly lower.

So I think both have sufficient levels of refrigerant ???

Now I set them both at 26 degrees amd room 1 will blow 15 degrees air, while room 2 will blow 18-18.5 degrees air.

What do you think may be the cause. Both aircons are 18 months old so right out of warranty.

Edited June 8, 2013 by jbrain

[IMHO]

Airconditioners can lose up to 5% efficiency per year, but it appears your commonly used one is the better of the two, which is odd..

First, what was the ambient temperature in each room to begin with? if #2 was cooler to start, the AC #2 may simply not have run at full duty cycle.

Failing that, have a good look at both the outdoor and indoor units and check for dust/dirt build-up, and adequate airflow.

[jbrain]

Airconditioners can lose up to 5% efficiency per year, but it appears your commonly used one is the better of the two, which is odd..

First, what was the ambient temperature in each room to begin with? if #2 was cooler to start, the AC #2 may simply not have run at full duty cycle.

Failing that, have a good look at both the outdoor and indoor units and check for dust/dirt build-up, and adequate airflow.

I don't understand what exactly you mean with full duty cycle, but I think after 12 hours continiously operating a full duty cycle should have completed.

I measure the temperature that comes out of the indoor unit right at the exit with both aircons identical settings and it seems that at maximum cooling setting they blow the same temperature, but at normal settings, one aircon is blowing air 3 degrees higher than the other.

Both compressors are at the same location.

The

[IMHO]

Airconditioners can lose up to 5% efficiency per year, but it appears your commonly used one is the better of the two, which is odd..

First, what was the ambient temperature in each room to begin with? if #2 was cooler to start, the AC #2 may simply not have run at full duty cycle.

Failing that, have a good look at both the outdoor and indoor units and check for dust/dirt build-up, and adequate airflow.

I don't understand what exactly you mean with full duty cycle, but I think after 12 hours continiously operating a full duty cycle should have completed.

I measure the temperature that comes out of the indoor unit right at the exit with both aircons identical settings and it seems that at maximum cooling setting they blow the same temperature, but at normal settings, one aircon is blowing air 3 degrees higher than the other.

Both compressors are at the same location.

The

OK, so one room is getting cooler inlet temps at the indoor unit, thus is operating a lower power (higher temp) levels.

[jbrain]

Airconditioners can lose up to 5% efficiency per year, but it appears your commonly used one is the better of the two, which is odd..

First, what was the ambient temperature in each room to begin with? if #2 was cooler to start, the AC #2 may simply not have run at full duty cycle.

Failing that, have a good look at both the outdoor and indoor units and check for dust/dirt build-up, and adequate airflow.

I don't understand what exactly you mean with full duty cycle, but I think after 12 hours continiously operating a full duty cycle should have completed.

I measure the temperature that comes out of the indoor unit right at the exit with both aircons identical settings and it seems that at maximum cooling setting they blow the same temperature, but at normal settings, one aircon is blowing air 3 degrees higher than the other.

Both compressors are at the same location.

The

OK, so one room is getting cooler inlet temps at the indoor unit, thus is operating a lower power (higher temp) levels.

That's correct. I have been testing all afternoon and just discovered something which might be interesting. The temperature sensor in the indoor units is at the right side of the unit.

In room 1 ( with the correct ambient temperature) the bed is at the left side of the unit, so all airflow " flaps " are directed to the left side.

In room 2 the bed is at the right side of the unit and the airflow is directed accordingly.

I just directed the airflow in room 2 to the left side, and noticed that within a few minutes the air the unit blew dropped by 3 degrees.

So I get the impression that the temperature sensor gets fooled by the temperature it blows, because all air is directed to the same side as the sensor. Do you think this is possible ?

Edited June 8, 2013 by jbrain

[IMHO]

Airconditioners can lose up to 5% efficiency per year, but it appears your commonly used one is the better of the two, which is odd..

First, what was the ambient temperature in each room to begin with? if #2 was cooler to start, the AC #2 may simply not have run at full duty cycle.

Failing that, have a good look at both the outdoor and indoor units and check for dust/dirt build-up, and adequate airflow.

I don't understand what exactly you mean with full duty cycle, but I think after 12 hours continiously operating a full duty cycle should have completed.

I measure the temperature that comes out of the indoor unit right at the exit with both aircons identical settings and it seems that at maximum cooling setting they blow the same temperature, but at normal settings, one aircon is blowing air 3 degrees higher than the other.

Both compressors are at the same location.

The

OK, so one room is getting cooler inlet temps at the indoor unit, thus is operating a lower power (higher temp) levels.

That's correct. I have been testing all afternoon and just discovered something which might be interesting. The temperature sensor in the indoor units is at the right side of the unit.

In room 1 ( with the correct ambient temperature) the bed is at the left side of the unit, so all airflow " flaps " are directed to the left side.

In room 2 the bed is at the right side of the unit and the airflow is directed accordingly.

I just directed the airflow in room 2 to the left side, and noticed that within a few minutes the air the unit blew dropped by 3 degrees.

So I get the impression that the temperature sensor gets fooled by the temperature it blows, because all air is directed to the same side as the sensor. Do you think this is possible ?

That sounds completely logical

[bankruatsteve]

A lot of the A/C units (Mitsubishi for sure) have a setting that makes the flaps go up/down/left/right on cycle. Maybe try that?