Friedrich FSHW091, Service And Parts Manual

Page: 44 / 171

44 PB
OPERATION
36k Sequence of Operation
2) Heating overload
c. If Ttube ≥ 136°F, the compressor will run at reduced frequency.
d. If Ttube ≥ 144°F, the compressor will stop and the indoor fan will run at preset speed.
a. If Ttube ≤ 126°F, the unit will return to its original operation state.
b. If Ttube ≥ 131°F, frequency rise is not allowed.
c. If Ttube ≥ 136°F, the compressor will run at reduced frequency.
d. If Ttube ≥ 144°F,the compressor will stop and the indoor fan will blow residue heat and then stop.
Designation of sensors Faults
Indoor ambient temperature
The sensor is detected to be open-circuited or short-circuited for successive 5
seconds
Indoor tube temperature
The sensor is detected to be open-circuited or short-circuited for successive 5
seconds
Outdoor ambient temperature
The sensor is detected to be open-circuited or short-circuited for successive 30
seconds
Outdoor tube temperature
The sensor is detected to be open-circuited or short-circuited for successive 30
seconds, and no detection is performed within 10 minutes after defrost begins.
Exhaust
After the compressor has operated for 3 minutes, the sensor is detected to be
open-circuited or short-circuited for successive 30 seconds.
Overload
After the compressor has operated for 3 minutes, the sensor is detected to be
open-circuited or short-circuited for successive 30 seconds.
②
Exhaust temperature protection of compressor
If exhaust temperature ≥ 208°F, frequency is not allowed to rise.
If exhaust temperature ≥ 217°F, the compressor will run at reduced frequency.
If exhaust temperature ≥ 230°F, the compressor will stop.
If exhaust temperature ≤ 194° F, the compressor has stayed at stop for at least 3 minutes, the compressor will resume its operation.
③
Communication fault
④
Module protection
Under module protection mode, the compressor will stop. When the compressor remains at stop for at least 3 minutes, the compressor will
resume its operation. If module protection occurs six times in succession, the compressor will not be started again.
⑤
Overload protection
If temperature sensed by the overload sensor is over 239 °F, the compressor will stop and the outdoor fan will stop with a time lag of 30
seconds. If temperature is below 203°F, the overload protection will be relieved.
If voltage on the DC bus is below 150V or over 420V, the compressor will stop and the outdoor fan will stop with a timelag of 30 seconds.
When voltage on the DC bus returns to its normal value and the compressor has stayed at stop for at least 3 minutes, the compressor will
resume its operation.
⑥
Faults of temperature sensors