Amana ANX, Service And Troubleshooting

Page: 61 / 160

SYSTEM OPERATION
61
NOTE: If more than two heater elements are on
the heater assembly, it will contain a second heat
sequencer, HR2, which will control the 3rd and 4th
heater elements if available. For the 3rd and 4th
heater elements to operate on a second stage heat
demand, the PJ4 jumper on the VSTB inside the MBE/
AEPF must be cut. With the PJ4 jumper cut, the VSTB
will run the blower motor on low speed on a “W1”
only demand. If the first stage heat demand, “W1”
cannot be satisfied by the heat pump, the temperature
indoors will continue to drop. The room thermostat
will then energize “W2” and 24Vac will be supplied
to HR2 on the heater assembly and the blower motor
will change to high speed. When the “W2” demand is
satisfied, the room thermostat will remove the 24Vac
from “W2” and the VSTB will remove the 24Vac from
HR2. The contacts on HR2 will open between 30 to 70
seconds and heater elements #3 and #4 will be turned
off and the blower motor will change to low speed. On
most digital/electronic thermostats, “W2” will remain
energized until the first stage demand “W1” is satisfied
and then the “W1” and “W2” demands will be removed.
2.3 When the “W1” heat demand is satisfied, the room
thermostat will remove the 24Vac from “E/W1” and the
VSTB rebetween 30 to 70 seconds and turn off the
heater element(s) and the blower motor ramps down to a
complete stop.
MBE/AEPF With Single Stage
GSZ, SSZ, ANZ, ASZ, and VSZ Heat Pumps
When used with a single stage GSZ, SSZ, ASZ, or VSZ
heat pumps, dip switch #4 must be set to the ON position
on the VSTB inside the MBE. The “Y” output from the
indoor thermostat must be connected to the yellow wire
labeled “Y/Y2” inside the wire bundle marked “Thermostat”
and the yellow wire labeled “Y/Y2” inside the wire bundle
marked “Outdoor Unit” must be connected to “Y” at the
heat pump. The orange jumper wire from terminal “Y1”
to terminal “O” on the VSTB inside the MBE/AEPF
must be removed.
3.0 Cooling Operation
On heat pump units, when the room thermostat is set to
the cooling mode, 24Vac is supplied to terminal “O” of the
VSTB inside the MBE/AEPF unit. The VSTB will supply
24Vac to “O” at the heat pump to energize the reversing
valve. As long as the thermostat is set for cooling, the
reversing valve will be in the energized position for cooling.
3.1 On a demand for cooling, the room thermostat
energizes “G” and “Y” and 24Vac is supplied to terminals
“G” and “Y/Y2” of the MBE/AEPF unit. 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 5 and 6. The VSTB will supply 24Vac to “Y” at
the heat pump.
3.2 The heat pump is turned on in the cooling mode.
3.3 When the cooling demand is satisfied, the room
thermostat removes the 24Vac from “G” and “Y/Y2” of the
MBE/AEPF and the VSTB removes the 24Vac from “Y” at
the heat pump. The heat pump is turned off and the blower
motor will ramp down to a complete stop based on the time
and 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/AEPF. 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/ AEPF. 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.