Changeover Control (Me1R Series) - Panasonic Urban Multi MX1R Series Service Manual

PACD011001C2
1.11 HR Changeover Control
The solenoid valve of the HR box is switched according to the indoor unit operating condition.
Condition
When the solenoid is operable, if the operating condition differs from the solenoid condition, the solenoid is
switched according to the above table.
However, the following conditions take precedence.
∗ 1 : Condition 2 results in heating stop units when no unit in the system is in cooling operation.
∗ 2 : Condition 1 results when a unit connected to the HR box is in heating thermostat ON condition
Function Urban Multi "MX1R, ME1R Series" Using R-407C
(ME1R Series)
Normal operation
Condition 1
Cooling
Condition 2
Heating
Indoor unit operating condition
1 Cooling
Heating stop ∗1
2 Heating thermostat OFF
Heating thermostat ON
3 Discharge oil return
4 Suction oil return
Defrost
during simultaneous cooling/heating operations.
Oil return, defrost
Oil return, defrost complete
Y3S Y2S
OFF ON
ON OFF
OFF OFF
ON ON
Function
Oil return, defrost
Discharge defrost
Condition 3
Discharge oil return
Suction defrost
Condition 4
Suction oil return
(VF006)
Y1S ON: Open
OFF: Closed
OFF
∗2
OFF
OFF
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