Reznor Q6SD (3ph) Unit Installation Manual - Manual (Page 12)

12
Defrost Control Board
Operational Informaton
• Terminals R - C must have 24V present between
them for the time delay and defrost sequences to be
operational.
• Jumpering 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.
• Jumpering 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. To switch from no-delay to delay remove
the pin from the no-delay pin location and move it to
the delay pin loction. The default setting is delay.
- Reciprocating compressors should only use this
setting in conjunction with an approved hard start
kit.
- 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 home owner
preference.
Optional Outdoor Thermostat
An outdoor thermostat can be installed in the fi eld with
2-stage electric heat by removing the orange wire from
the E terminal on the terminal block and connecting to the
outdoor thermostat. Connect the other side of the outdoor
thermostat to W2 from the thermostat.
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 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. A two stage heat 24VAC
thermostat is used when aa two stage electric heater kit
is installed. As previously noted, a fi eld 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.
Thermostat Connections
• The Q6SD heat pump requires a 2-stage cooling/
heating thermostat that must operate in conjunction
with installed accessories. The 2-stage thermostat
also prevents simultaneous operation of the heating
and cooling units.
• The low voltage wires must be properly connected
to the units low voltage terminal block. See Figure 8
(page 16) for 208/230V units or Figure 9 (page 17) for
430V units. Recommended wire gauge and lengths for
typical thermostat connections are listed in Table 3.
• The thermostat should be mounted about 5 feet
above the fl oor on an inside wall. DO NOT install the
thermostat on an outside wall or any other location
where its operation may be adversely affected by radiant
heat from fi replaces, sunlight, or lighting fi xtures, and
convective heat from warm air registers or electrical
appliances. Refer to the thermostat's instruction sheet
for detailed mounting and installation information.