Mitsubishi Electric MXZ-SM72TAM-U1 Service Manual page 8

Amb. decreasing
Amb. increasing
a
−25°C
[−13°F]
When the set temperature ranges overlap, the previously set pattern (1, 2 or 3) has a priority.
The stage 1 has the highest priority, 2 the second and then 3.
• Based on above chart listed the sequence of operation on "On ambient decrease"
- Stage 1: (TH7 = > 50°F [10°C]): the outdoor unit runs in HP mode.
- Stage 2: (TH7 = 50 to -13°F [10 to -25°C]): the outdoor unit runs in HP mode with auxiliary heating.
- Stage 3: (TH7 = < -13°F [-25°C]): Auxiliary heating only (Outdoor unit is OFF).
• Based on above chart listed the sequence of operation on "On ambient increase"
- Stage 3: (TH7 = < 32°F [0°C]): Auxiliary heating only (Outdoor unit is OFF).
- Stage 2: (TH7 = > 32 to 68°F [0 to 20°C]): Auxiliary heating with outdoor unit in HP mode.
- Stage 1: (TH7 = > 68°F [20°C]): Outdoor unit in HP mode only.
■ Locally procured wiring
• A basic connection method is shown.
(i.e. interlocked operation with the electric heater with the fan speed setting on high)
Remote control Board
Electric
Heater
• For relay X, use the specifications given below operation coil.
Use the diode that is recommended by the relay manufacturer at both ends of the relay coil.
- Rated voltage: 12 V DC
- Power consumption: 0.9W or less
• The length of the electrical wiring for the PAC-YU24HT is 2 meters (6-1/2 ft)
• To extend this length, use sheathed 2-core cable. Do not extend the cable more than 10 meters (32 ft).
- Control cable type: CVV, CVS, CPEV, or equivalent
- Cable size: 0.5 mm² to 1.25 mm² (AWG22 to AWG16)
• Recommended circuit
Wiring diagram
OCH800A_8
b c
0°C 10°C
[32°F] [50°F]
Relay circuit
X
Preparations in the field
R
1-phase power
S
supply
208V, 230V/60Hz
R
S
Control board
Stage 1
- Outdoor unit HP operation
- Defrost : Heater contact ON signal
- Other than defrost : Contact OFF
Stage 2
- Outdoor unit HP operation
- Heater contact ON signal
Stage 3
- Outdoor unit OFF (Standby)
- Heater contact ON signal
TH7 = Outdoor temperature
d
20°C
[68°F]
Adapter
Red 1
White 2
X
Red 1
+
Red 2
Maximum cable length
is 10 m (32ft)
88H
H1
FS1
FS2
88H H2
FS1
FS2
26H
88H
CN24
Indoor unit
control board control board
Dip switch
SW5-4 "ON"
CN24
CN22
FS1, 2 ----- Thermal fuse
H1, H2 ----- Heater
26H --------- Overheat protection
thermostat
88H --------- Electromagnetic contactor
Outdoor unit