Goodman Mfg RT6100004R13 - Manual (Page 48)

SERVICING
48
rate programmed in the motor.
4.0 Heating Operation
On heat pump units, when the room thermostat is set to the
heating mode, the reversing valve is not energized. As long
as the thermostat is set for heating, the reversing valve will be
in the de-energized position for heating except during a
defrost cycle. Some installations may use one or more
outdoor thermostats to restrict the amount of electric heat
that is available above a preset ambient temperature. Use of
optional controls such as these can change the operation of
the electric heaters during the heating mode. This sequence
of operation does not cover those applications.
4.1 On a demand for first stage heat with heat pump units, the
room thermostat energizes “Y” and “G” and 24Vac is
supplied to “G” and “Y/Y2” of the MBE. The VSTB will turn
on the blower motor and the motor will ramp up to the
speed programmed in the motor based on the settings of
dip switch 1 and 2. The VSTB will supply 24Vac to “Y” at
the heat pump and the heat pump is turned on in the
heating mode.
4.2 If the first stage heat demand cannot be satisfied by the
heat pump, the temperature indoors will continue to drop.
The room thermostat will then energize terminal “W2” for
second stage heat and 24Vac will be supplied to “E/W1”
of the MBE. The VSTB will supply 24Vac to heat
sequencer, HR1, on the electric heater assembly.
4.3 HR1 contacts M1 and M2 will close within 10 to 20
seconds and turn on heater element #1. At the same
time, if the heater assembly contains a second heater
element, HR1 will contain a second set of contacts, M3
and M4, which will close to turn on heater element #2.
Note: If more than two heater elements are on the heater
assembly, it will contain a second heat sequencer, HR2,
which will control the 3
rd and 4 th heater elements if available.
For the 3 rd and 4 th heater elements to operate on a third
stage heat demand, the PJ4 jumper on the VSTB inside
the MBE and AEP* must be cut. If the second stage heat
demand, “W2”, cannot be satisfied by the heat pump, the
temperature indoors will continue to drop. The room thermo-
stat will then energize “W3” and 24Vac will be supplied to “W/
W2” of the MBE. The VSTB will supply 24Vac to HR2 on the
electric heater assembly. When the “W3” demand is satis-
fied, the room thermostat will remove the 24Vac from “W/W2”
of the MBE and AEP*. The contacts on HR2 will open
between 30 to 70 seconds and heater elements #3 and #4 will
be turned off. On most digital/electronic thermostats,
“W3” will remain energized until the first stage de-
mand “Y” is satisfied and then the “G”, “Y”, “W2” and
“W3” demands will be removed.
4.4 As the temperature indoors increase, it will reach a point
where the second stage heat demand, “W2”, is satisfied.
When this happens, the room thermostat will remove the
24Vac from “E/W1” of the MBE. The contacts on HR1 will
open between 30 to 70 seconds and turn off both heater
element(s). The heat pump remains on along with the
blower motor because the “Y” demand for first stage heat
will still be present.
4.5 When the first stage heat demand “Y” is satisfied, the
room thermostat will remove the 24Vac from “G” and “Y/
Y2” of the MBE and AEP*. The VSTB removes the 24Vac
from “Y” at the heat pump and the heat pump is turned off.
The blower motor will ramp down to a complete stop
based on the time and rate programmed in the motor
control.
5.0 Defrost Operation
On heat pump units, when the room thermostat is set to the
heating mode, the reversing valve is not energized. As long
as the thermostat is set for heating, the reversing valve will be
in the de-energized position for heating except during a
defrost cycle.
5.1 The heat pump will be on and operating in the heating
mode as described the Heating Operation in section 4.
5.2 The defrost control in the heat pump unit checks to see
if a defrost is needed every 30, 60 or 90 minutes of heat
pump operation depending on the selectable setting by
monitoring the state of the defrost thermostat attached to
the outdoor coil.
5.3 If the temperature of the outdoor coil is low enough to
cause the defrost thermostat to be closed when the
defrost board checks it, the board will initiate a defrost
cycle.
5.4 When a defrost cycle is initiated, the contacts of the
HVDR relay on the defrost board open and turns off the
outdoor fan. The contacts of the LVDR relay on the
defrost board closes and supplies 24Vac to “O” and “W2”.
The reversing valve is energized and the contacts on HR1
close and turns on the electric heater(s). The unit will
continue to run in this mode until the defrost cycle is
completed.
5.5 When the temperature of the outdoor coil rises high
enough to causes the defrost thermostat to open, the
defrost cycle will be terminated. If at the end of the
programmed 10 minute override time the defrost thermo-
stat is still closed, the defrost board will automatically
terminate the defrost cycle.
5.6 When the defrost cycle is terminated, the contacts of the
HVDR relay on the defrost board will close to start the
outdoor fan and the contacts of the LVDR relay will open
and turn off the reversing valve and electric heater(s). The
unit will now be back in a normal heating mode with a heat
pump demand for heating as described in the Heating
Operation in section 4.
S-60 ELECTRIC HEATER (OPTIONAL ITEM)
Optional electric heaters may be added, in the quantities
shown in the specifications section, to provide electric
resistance heating. Under no condition shall more heaters
than the quantity shown be installed.
The low voltage circuit in the air handler is factory wired and
terminates at the location provided for the electric heater(s).
A minimum of field wiring is required to complete the instal-