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SiBE28-804
Troubleshooting by Remote Controller Display / LED Display
Troubleshooting
237
<Diagnosis of inadequate refrigerant>
In heating operation
(1) As suction superheat degree increases due to gas shortage, the electronic expansion valve
tends to open (opens fully) to avoid overheat operation.
(2) As suction superheat degree increases due to gas shortage, compressor frequency
decreases because suction superheat degree is controlled in order to prevent oil to the
outdoor heat exchanger from being retained.
(3) Because of (1) and (2) above, evaporator capacity and compressor frequency decrease
despite a large difference (large load) between temperature set by the remote controller and
indoor suction temperature, resulting that high pressure cannot be maintained and heating
capacity becomes unavailable. Also a decrease in evaporator capacity frequently puts the
system in defrost operation.
(4) If gas shortage worsens, high pressure becomes smaller than saturated pressure equivalent
to indoor heat exchanger temperature (or indoor suction temperature).
Heating
(Maintains a certain
level of high pressure)
Indoor heat exchanger temperature (Th2)
Indoor suction temperature (Th1)
Electronic expansion valve control by avoiding superheat operation
In response to decreased evaporator capacity
caused by gas shortage, capacity is controlled in
the inverter in order to maintain high pressure,
which resulting in a rise in frequency.
Drooping control by suction superheat degree
(Prevention of oil to heat exchanger from
being retained)
Suction superheat degree increases.
A decrease in evaporator capacity frequently
puts the system in defrost operation.
When frequency drops to the
lowest, a decrease in low
pressure becomes larger.
High pressure
(Pressure sensor)
Low pressure
(Middle of heat exchanger Tm)
Suction superheat degree
Compressor frequency
Electronic expansion valve
Adequate level
Inadequate
(Degree of inadequate refrigerant)
Gas shortage warning
As compressor frequency
decreases, high pressure
decreases.
Abnormal gas shortage
Reaches the lowest frequency
The maximum opening degree of the
electronic expansion valve (480 pulses)
Summary of Contents for FHQ100BUV1B x 2
Page 13: ...SiBE28 804 2 ...
Page 19: ...Model Name and Power Supply SiBE28 804 8 General Information ...
Page 29: ...Specifications SiBE28 804 18 Specifications ...
Page 33: ...Wired Remote Controller SiBE28 804 22 Remote Controller 1 2 Installation ...
Page 34: ...SiBE28 804 Wired Remote Controller Remote Controller 23 ...
Page 93: ...Outdoor Unit Fan Speed Control SiBE28 804 82 Functional Description ...
Page 131: ...Test Run and Operation Data SiBE28 804 120 Test Operation ...
Page 251: ...Troubleshooting by Remote Controller Display LED Display SiBE28 804 240 Troubleshooting ...
Page 277: ...PCB Layout SiBE28 804 266 Appendix ...
Page 297: ...RZQ100 140C7 RZQS125 140C7V1B SiBE28 804 286 Removal Procedure ...
Page 311: ...SiBE28 804 iv Index ...