Gree TERRA09HP230V1A Installation, Service & Troubleshooting page 19

System Operation 9,000/12,000 btuh Models, cont.
Basic Functions
Defrost Process
1) The unit will enter defrost when the following conditions are met:
A. Outdoor ambient <= 410 F
B. Compressor had accumulated more than 3 hours of operation in heating mode
C. The outdoor coil <= 320 F
Note: The compressor runtime will be cleared when the outdoor ambient is > 410 F or when the compressor has started
up after changing to cooling or drying mode and defrost has finished. The runtime will not be cleared when the unit has
stopped after reaching the setpoint temperature, a protection fault or changing to fan mode.
There are 3 perimeters used in the defrost algorithms, Outdoor ambient(T
a calculated T
compensation
T is calculated by the following:
compensation
D. After power-up, for the first defrost T
E. T tube > 360 F then T
outdoor
F. T tube <= 360 F then T
outdoor
2) When heating has operated continuously for 45 minutes, or accumulated for 90 minutes, the unit will enter defrost
mode in 3 minutes after meeting any of the conditions below:
A. Outdoor ambient >= 410 F and outdoor coil <= 280 F
B. 280 F <= T ambient< 410 F, T
outdoor
C. 230 F <= T ambient < 280 F <= T
outdoor
D. 140 F <= T ambient < 230 F , T
outdoor
3) During defrost, if run time for the compressor does not reach 3 minutes, the defrost cycle will not start for the next 2
hours. At that time the compressor stops operation and 30 seconds later the outdoor fan will stop. 30 seconds after this the
4-way reversing valve will de-energized. Following another 30 second delay, the compressor will increase its compressor
speed for defrosting. Defrosting will last for 450 seconds or until the T
sor will decrease it compressor speed for 30 seconds, then will stop. In another 30 seconds the 4-way valve will energize,
the 60 seconds later the compressor and outdoor fan will start. The compressor speed for defrosting will be 85hz.
During Defrost mode, a "H1" will be displayed on the indoor front panel display indicating the user selected mode has
been overridden and the system is performing a outdoor coil defrost operation.
Product Introduction
= 32 0 F
compensation
= 32 0 F
compensation
= 37 0 F
compensation
tube <= 210 F
outdoor
tube <= 180 F
outdoor
tube -T
outdoor compensation
ambient), Outdoor tube(T
outdoor
<= (T ambient - 370 F)
outdoor
tube >= 500 F, at this temperature the compres-
outdoor
tube) and
outdoor
19