Sanyo Big PACi 18 Series Technical Data & Service Manual page 226

(2) [Alarm P26]
Start of defect diagnosis
Was everything OK
when to in the diagnosis
flow of alarm P29 were
checked?
Yes
Is the heat sink
connected properly to the
HIC PCB? (Loose screws and
thermal conduction
putty)
Yes
Is the high-pressure
for the refrigerant cycle within
the range? (High load
operating?)
(Not operating
Yes
on high load)
Does the alarm
P26 occur when the
U / V / W wires (pink/white/blue)
are disconnected from the
HIC PCB and
operation was
started?
Yes
(An alarm other than the alarm P26 occur)
Was everything OK
when to in the diagnosis
flow of alarm P29 were
checked?
Yes
Replace the compressor
Start-up failure of the compressor (will not start up)
Related parts
HIC PCB (Model: [706-type, 906-type] HIC-C1155GDXH8)
Outdoor unit control PCB (Model: [706-type, 906-type] CR-C906VH8)
Filter PCB (Model: [706-type, 906-type] FIL-C906VH8)
No
Implement the same check processes for
No
Correct the connection between the HIC PCB and heat sink.
Abonormal temperature rise in the HIC PCB is prevented by radiating the heat, with HIC being
coated evenly with thermal conduction putty and the heat sink being attached firmly to the HIC
PCB by screws. The HIC PCB cannot radiate heat properly if the screws are loose or the
thermal conduction putty is not applied correctly. Consequently, the temperature inside the
HIC PCB can rise abnormally and the alarm P26 occurs.
Operating on high load.
Recovery methods differ in accordance with the cause.
No
Recharge refrigerant
Replace the thermistor
Repair the pipes, etc.
1. Potential Causes
Refrigerant overcharge
Has the refrigerant been overcharged?
* Verifying Overcharge
There is no problem if the difference between the temperature on the indoor unit "E2" and
the saturated temperature of the outdoor unit's gas pipe service valve pressure is within 2
during the heating mode. Any of the following could be the reason if the former is two or
more degrees lower than latter.
Faulty operations of the outdoor unit electronic expansion valve.
Pipe blockage, crushed pipes, etc.
(Assumed to be on the liquid pipes during the cooling mode and the gas pipes during the
heating mode.)
C1 and C2 thermistor error on the outdoor unit (during the cooling mode.)
E1 and E2 thermistor error on the indoor unit (during the heating mode.)
2. Temperature on the high-pressure side during normal operations.
Cooling: Temperature of the C2 thermistor on the outdoor unit is approximately between
45 and 55 .
Heating: Temperature of the E2 thermistor on the indoor unit is approximately between
40 and 50 .
* There are cases in which the above temperatures will be lower depending on the
operation conditions.
No (alarm P26 output)
Replace the HIC PCB.
The HIC PCB is considered faulty if the alarm P26 occurs even if the compressor is not
operating owing to the U, V and W wires being disconnected.
Replace the HIC PCB.
No
Implement the same check processes for
Potential problems are most likely in accordance with the following sequence when it is
determined that the PCB is trouble with an alarm P26.
1. HIC PCB
2. Outdoor unit control PCB
3. Filter PCB
Replace the relevant PCBs in accordance with the above sequence.
5-9
to in the diagnosis flow of alarm P29.
to in the diagnosis flow of alarm P29.
5