Outline of Control (Indoor Unit)
SiUS28-902_B
38
Function
6.7.2 Heat Pump Lockout Mode
During heating operation, users can select an electrical heater for heating. For this, signals are
sent using ABC terminal of outdoor unit PCB.
When the hot-water heating signal is received from the outdoor unit PCB, heating operation is
performed only with the heater as manual backup operation. The ON/OFF conditions for this
electrical heater are shown below.
Thermostat OFF/Stop operation
Thermostat step 1 H/P
Fan: Normal operation
Timer count: 5 minutes
Timer count: 5 minutes
Timer count: 5 minutes
Timer clear
Timer clear
Timer clear
Fan H tap
120 seconds
∗
3
Fan H tap
120 seconds
∗
3
Thermostat ON
Condition A
Electrical heater step setting 01
Thermostat step 2 = "ON"
Thermostat step 3 = "ON"
Condition B
Condition B
Condition B
Thermostat step 2 = "OFF"
Thermostat step 3 = "OFF"
• Thermostat OFF
• Stop operation
Heater 1 ON
Heater 2 OFF
Fan H tap
∗
1
Heater 1 ON
Heater 2 ON
Fan H tap
∗
1
Heater 1 ON
Heater 2 ON
Fan H tap
∗
1