Northern Heatpump NorthStar RD-WE-096 Installation & Operating Instructions Manual - page 25
08/19/2014
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NI701
Disconnect – field provided external safety disconnect is required, see nameplate max amps.
Grounding – route and install the proper size ground conductor between the ground lug above the compressor
contactor and the building service entrance panel ground bus. This must be a conductor wire size according to
NEC code for the total amp rating of the installed model. The conduit is not sufficient ground conductor.
WARNING
USE ONLY COPPER WIRE FOR CONNECTION TO THE CIRCUIT BREAKER TERMINALS AND
INSIDE THIS PRODUCT’S CABINET.
WARNING
TO AVOID THE RISK OF ELECTRIC SHOCK OR DEATH, WIRING TO THE UNIT MUST BE
PROPERLY GROUNDED. FAILURE TO PROPERLY GROUND THE UNIT CAN RESULT IN A
HAZARD LEADING TO PERSONAL INJURY OR DEATH.
Control Wiring
Operating Aquastat (or Buffer Tank Controller, HP-BTC)
The closed-for-heat contact is simply wired to terminal block R and HW. For set point and differential, see
previous section on operating temperature consideration and compressor short cycling.
Loop Pump
The internal terminal provides 240 (L1 and L2) 10A fused output for the loop pump or flow center.
Hydronic Main Pump
The external circulating pump for the buffer tank or large single zone system can be operated from the internal
“HYD PUMP” terminal block. Note this is a 10A fused 240V output that operates coincident with the HW
input. If the hydronic loop pump is 120V, you must use an isolation relay from this internal terminal block
connection.
Forced-Air Air Handler/Water Coil
The room thermostat for the forced air coil and its appropriate control mechanism must operate the air handler
and the pump for the water coil. Also, if it is to be used for cooling, the thermostat must provide the O terminal
reversing valve O function to this Geo unit and appropriately control the compressor HW terminal.
Buffer Tank Controller, Optional
This controller can be considered a central wiring point for all zone thermostats, zone pumps, forced air
thermostat, forced air water coil pump, forced air blower (gas furnace blower), etc. The HP-BTC installation
manual provides complete details and drawings for all external hookup devices including the connection
between HP-BTC and this NHP geo unit.
Note:
Once the roomstat is set for COOL it must remain in COOL for the summer season. If it is turned off or
switched back and forth, the buffer tank could actually heat up in summer.