External Input Function Setting - Hitachi mini-HNRQ1 Series Service Manual

2.2 External Input Function Setting

The following signals can be received by the outdoor unit PCB.
(1) Input Fixing Heating Operation Mode (Control Function No.1),
Input Fixing Cooling Operation Mode (Control Function No.2)
When the input terminals for the setting operation mode on the outdoor unit PCB are short-circuited,
the operation mode can be set at the cooling or heating mode.
Short Circuit between Terminals 1 and 2 of CN1: Fixed Heating Operation Mode
Short Circuit between Terminals 2 and 3 of CN1: Fixed Cooling Operation Mode
During this set heating (or cooling) mode, no cooling (or heating) operation is possible. The indoor
units under the cooling or dry operation (or heating operation) will be changed to the Thermo-OFF
condition during this mode, and stoppage code No. "20" is given.
– Setting Example
Fixing Heating Operation at Input 1 (between 1 and 2 pins of CN17)
Fixing Cooling Operation at Input 2 (between 3 and 2 pins of CN17)
(Heat)
(2) Input Demand Stoppage (Control Function No.3)
When the input terminals for Demand Stoppage on the outdoor unit PCB are short-circuited while
running, the compressor is stopped. (In this case, the indoor unit(s) is put under Thermo-OFF condition.
Cooling operation: Air-flow setting, Heating operation: Lo setting)
The stoppage code No. "10" is given. If the input terminals are opened, operation is resumed.
Note:
When demand control (ON/OFF) is performed, it is recommended that the control (ON/OFF) time is set appropriately according
to the heat load. Also, set the demand control time approximately once in 15 minutes at the minimum in consideration for saving
energy.
*Thermo-ON: The outdoor unit and some indoor units are running.
Thermo-OFF: The outdoor unit and some indoor units stay on, but don't run.
Outdoor unit
3P Connector PCB
(Cool)
EXTERNAL INPUT/OUTPUT AND FUNCTION SETTING
X1:Auxiliary Relay
X2:Auxiliary Relay
SS3: Operation mode fixing switch
SS2: Changeover switch
(Heat) (Cool)
Control circuit
155
Power sopply