Service manual

CONTROL SYSTEM
11.2.7 Dry Contacts
Dry contacts are used to interface the system with an external building management system
(BMS).
 Night
input. Switches the system to night mode when closed.
During night mode, the outdoor unit speed will be reduced in order to reduce the system
noise level.
 SB input. System will be turned to Stand-by whe
n the contact is closed.
 Pow
er Shedding input. Limits the maximum power consumption when closed.
 Forced Mo
de input. Used to force the operation mode of the system
 Alarm output indicate
s a failure at the system.
Alarm output will be activated when there in the following ODU Faults/Protections
1 to 6, 8 to 22, 24, 25, 27 and 28.
Alarm output will be OFF when the Fault/Protection is cleared.
11.2.8 Temperature Sensors
CTT – Compressor Top Temperature
OAT – Outdoor Air Temperature
SUCT – Suction/Evaporating Temperature
OCT – Outdoor Coil (heat exchanger) Temperature
HST – Heat Sink Temperature
RGT1..4 – Indoor Unit 1..4 Returned Gas Temperatures
11.2.9 Base Heater
Heating element designed to melt any ice that is accumulated on the outdoor unit base
during low heating operation.
Revision 0
11-3