GSZH5 Service Manual
61
SYSTEM OPERATION
Operation
Most expansion valves used in current Amana Heat Pump products use an internally checked expansion valve. This type
of expansion valve does not require an external check valve as shown above.
Operation
SEQUENCE OF OPERATION
Refer to the installation instructions and wiring
1.0 Cooling Operation
1.1 On a demand for cooling, the room thermostat
energizes “G” and “Y” and 24Vac is supplied to “Y” at the
condensing unit and the “G” terminal on the EBTDR board.
The compressor and condenser fan are turned on and
after a 7 second on delay, the relay on the EBTDR board is
energized and the blower motor starts.
1.3
thermostat removes the 24Vac from “G” and “Y”.
1.4
On a demand for heat, the room thermostat energizes
“W1” and 24Vac is supplied to heat sequencer, HR1, on the
heater assembly.
The contacts M1 and M2 will close within 10 to 20
seconds and turn on heater element #1. The normally
closed contacts on the EBTDR are also connected to
terminal M1. When M1 and M2 close, the blower motor
will be energized thru the normally closed contacts on the
EBTDR board. 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.