Mitsubishi Electric MXZ-24UV-E1 Service Manual page 32

• When the operation frequency does not go up from lowest frequency.
H H Check of HPS
Start
1. Disconnect the connector CN722 in the electronic control P. C. board.
2. Check the resistance of HPS after 1 minutes have passed since the outdoor unit power supply was turnd off.
Check the resistance between
each terminal?
0"
Return CN722 to former.
Turn on power supply to the indoor and outdoor unit.
3 minutes lator, EMERGENCY OPERATION starts.
Yes
Is HPS protection displayed
immediately after compressor
starts.
Yes
Normal
I I The other cases
In the case that the indoor fan and outdoor fan operate but the compressor does not operate, it causes that the
high pressure switch can be operated once.
First of all, check the high pressure switch can be shorted, turn OFF the power and turn ON again 1 minute later.
Indoor unit dose not operate. (difference modes)
• When you try to run two indoor unit simultaneously, one for cooling and the other for heating, the unit which
transmits signal to the outdoor units earlier decides the operation mode. The other unit indicates as shown in
the figure below.
• When the above situation occurs, set all the indoor units to the same mode, turn OFF the indoor units, and
then turn them back ON.
• Though the top of the indoor unit sometimes gets warm, this does not mean malfunction. The reason is that
the refrigerant gas continuously flows into the indoor unit even while it is not operating.
OPERATION INDICATOR
Infinity
Replace HPS (63H1).
No
Replace the electronic control P. C. board.
Lighting
32
Flashing