10
Ambient Sensor Mounting
For optimum performance of the heat pump system, the
ambient sensor must be mounted on the outside of the
1. Remove the mounting bracket wire tied to the control
bracket and all hardware included in the packet.
2. Remove star bushing from 7/8” hole in corner panel of
.
3. Route the ambient sensor through the 7/8” hole in the
corner panel of the unit, and then through the 7/8” hole
in the mounting bracket.
4. Route the sensor through the star bushing. Use the star
bushing to secure the mounting bracket to the unit.
5. Secure the ambient sensor inside the plastic clip and
secure it to the mounting bracket with the screw and
nut provided.
6. Install one spacer nut between the plastic clip and
mounting bracket.
7. Bend the mounting bracket into position and screw the
mounting bracket to the corner panel.
Defrost Board Operation
1. Heat Pump operates in heating mode until the
combination of outdoor ambient and outdoor coil
temperatures initiate a defrost cycle. The outdoor coil
temperature must be at or below 25.5°F before the
defrost cycle begins.
2. There must be a minimum of 35 minutes between
defrost cycles. After this time, coil temperature & outdoor
ambient will drive a call for defrost after conditions are
met continuously for 30 seconds before a defrost cycle
is initiated.
3. Outdoor fan is off during defrost operation.
4. The defrost cycle ends when the outdoor temperature
reaches 50°F-80°F, dependent on TERM TEMP jumper
position (default 70°F-no jumper) or if the defrost
terminate time of 11 minutes is reached.
See "Control Board Status Indicators" for operation
Forced Defrost When the Following Conditions
are Met:
• LPS and HPS are closed
• Y1 input is active
• O input is either active or inactive
• TEST terminals shorted for more than three seconds
Compressor will start and unit will operate in DEFROST
mode.
Unit will run in DEFROST mode after pins have been
shorted at least 3 seconds regardless of whether short
is removed or not.
Qualifying conditions of minimum ambient or coil
temperature do not need to be met when the unit is forced
into defrost. If the short across the TEST pins exist, the
unit will stay in DEFROST as long as the short remains
or until the TERMINATE TIME is reached (11 minutes).
This will happen regardless of coil temperature.
W2 OUT is active during this time if the O input is inactive.
If after 11 minutes the short remains, the unit shall not
run in any mode and the display shall flash 'DF' until the
short is removed.
W2 OUT shall remain on during the whole time that the
short exists, if the O input is inactive.
Crankcase Heater (CCH) Operation
The outdoor temperature is measured by the ambient
temperature sensor. The CCH is enabled during first 2
minutes after board power up regardless of any other
condition.
• The CCH is disabled during compressor operation.
• The CCH is disabled when OD temperature > 70F.
• The CCH is enabled when OD temperature < 71F.
Optional Outdoor Thermostat (Field Supplied)
An outdoor thermostat can be installed in the field with
2-stage electric heat by removing the orange wire from the
W2
terminal on the unit terminal block and re-connecting
it to the outdoor thermostat. Connect the other side of
the outdoor thermostat to
W2
on the unit terminal block
.
.
Optional Electric Heater Kits
Optional electric heater kits are available in 5 kw through
20 kw heating capacities. Single package heat pumps
are designed to allow optional electric heat to be field
installed as required by the building’s particular heating
load. The options available for each unit are shown in the
heater kit installation instructions. A heating/cooling 24V
thermostat should be used when an electric heater kit is
installed.
NOTE:
A 2-stage heating thermostat is required
if installing a 2-stage heater kit. As previously noted, a
field installed circuit breaker kit is available as a means
of electrical disconnect for the unit. Install the heater kits
as directed by the instructions supplied with the heater
kit. Follow all cautions and warnings as directed.
Figure 6. Ambient Sensor Mounting
Bolt
Nut
Nut
Ambient Sensor
Plastic Clip
Star Bushing
