NorAire EB-HPH Series, Installation & Operating Instructions Manual

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09/06/2018 25 BI903
Outdoor Unit (ODU) Connections
Located on the upper right hand corner of the NorAire controller is a 6 place terminal strip
labeled “HEAT PUMP”. This is where the ODU interfaces (low voltage wiring) to the IDU. This
allows the IDU to control the ODU based on various system variables.
R is 24VAC
Y is compressor contactor
O is reversing valve
C is 24VAC common
D is Defrost
NOTE: Defrost is an input to the IDU and an output from the ODU
Defrost NOTE:
The NorAire controller has nothing to do with starting or ending a
defrost cycle. “D” input in the diagram above in an optional hookup. If connected, J3 will
determine what the NorAire does with this defrost input.
J3:
This jumper is used to enable or disable the Electro-Boiler while the heat pump is in defrost.
With the jumper ON, the Electro-Boiler will go to full output whenever the heat pump is in
defrost. With the jumper OFF, the Electro-Boiler will not be used during defrost (unless in
BOOST mode at the time of defrost).
Factory default is OFF.
“DEF OUT”
: If special circumstances arise where the system is struggling to adequately defrost. A
bypass can be added to “short circuit” the NorAire return and supply during defrost to speed up the
process. “DEF OUT” would be used to drive the mechanism needed to initiate this bypass sequence
during defrost. This is not needed in most applications.