11
To set the cycle timer, place the timing pin on the defrost
control board to the desired time interval post.
NOTE:
All
units are shipped from the factory with the default time
setting of 30 minutes.
Defrost Control Board
Operational Information
• Terminals
R
-
C
must have 24V present between
them for the time delay and defrost sequences to be
operational.
• Jumping
the
T2
-
DFT
test pins will communicate to
the board that the defrost thermostat is closed (if the
compressor is running). The defrost T-stat tells the
board whether a defrost cycle needs to be started or
terminated.
NOTE:
The
defrost T-stat is closed at 32° F or below
and is open at 68° F or above, but it’s state is unknown
if the temperature is between 32° F and 68° F.
• With the DFT closed, the unit will run for 30/60/90
minutes in heat mode and then defrost the outdoor
coil. The defrost will turn off the outdoor fan, turn on
the compressor, and raise the coil temperature to 68°
F. This will open the DFT and terminate the defrost. If
the DFT does not open, the defrost will end after 10
minutes.
• Jumping
the
TEST
terminal to the
C
(common) terminal
(while the compressor is in heat mode) will over-ride
the defrost board and initiate a faster defrost test in
5, 10 or 15 seconds as determined by the 30, 60 or
90 minute defrost pin settings (factory setting is 30
minutes).
- This also bypasses the compressor off delay when
the unit goes into defrost test. If unit is kept in defrost
test, the delay will be bypassed when the test is
terminated by the processor.
NOTE:
If the jumper is removed before the test is over,
the processor will perform the remainder of a normal
defrost as noted above.
• The delay/no-delay pin affects compressor operation
during defrosts. The default setting is delay. To switch
from delay to no-delay, remove the pin from the
delay
pin location and move it to the
no-delay
pin location.
- Scroll compressors that have noise issues while
going into or coming out of defrost should use this
30 second delay to reduce the defrost noise.
Normal Defrost Procedure
To test normal defrost operation when the temperature is
above 35° F, jumper
R
to
DFT
on the board and allow the
unit to run for 30 minutes. Defrost will continue until the
R
to
DFT
jumper is removed or for 10 minutes. Remove
the jumper.
The 5 minute time delay feature can be shortened 1 time
to 1 second by jumping the
Test
to
C
terminal. Remove
the jumper and repeat as desired.
NOTE:
If jumper is left
on the
Test
to
common
pins permanently, the defrost
cycle will be inoperable.
Defrost Test Procedure
1. Jumper
T2
to
DFT
at the test terminals.
2. With unit running in heat mode, jump the
TEST
terminal
to the
C
(common) terminal near it. The board will
speed up and enter defrost mode in 5/10/15 seconds,
depending on the defrost time selection. Compressor
delay will not function during speed-up.
NOTE:
Manually
initiating a defrost will cause the compressor to run
continually when entering defrost.
3. This test will end in 5 seconds if the
TEST
- common
short is not removed.
4. Remove both the short and the
T2
to
DFT
jumper to
terminate the defrost cycle. The 30 second compressor
delay should operate normally.
5. Test is complete, reset thermostat to the equipment
owner's preference.
Optional Electric Heater Kits
Optional fi eld-installed electric heater kits are available in
10 kw through 36 kw heating capacities. Split System Heat
Pumps are designed to allow optional auxiliary electric
heat to be fi eld installed as required by the building’s
particular heating load. The options available for each
unit are shown in the heater kit installation instructions.
Install the heater kits as directed by the instructions
supplied with the heater kit. Follow all cautions and
warnings as directed.
