Mitsubishi Electric CITY MULTI PUHY-P108 Service Handbook page 253

[ IX Troubleshooting ]
Error Code
2502 Drain pump
failure
(The error
code blinks on
the indoor unit
in trouble.)
Drain pump fail-
ure
(The error code
blinks on all the
indoor units in the
system with one
outdoor unit.)
Error definition and error
detection method
When the drain sensor (1) Drain pump malfunction
detects water or its tip be- (2) Clogged drain pump intake
comes immersed in wa- (3) Clogged drain pipe
ter during drain pump (4) Return water from drain
operation.
When the drain sensor (1) Drain pump malfunction
detects water or its tip be- (2) Clogged drain pump intake
comes immersed in wa- (3) Clogged drain pipe
ter during drain pump (4) Return water from drain
operation on stopping in-
door units.
Cause
pipe (Improper installation)
pipe (Improper installation)
- 244 -
Check method and remedy
1) Check for drain pump malfunc-
tion
Check whether there is water
in the drain pan.
When the water level is ap-
proximately 10mm [13/32"]
from the bottom of the drain
pan, the drain pump may be
normal.
Check whether the drain
pump operates properly.
Check whether the resis-
tance of the drain pump is
normal or the drain pump
operates normally when the
power supply is applied.
2) Check for clogged drain pump
intake.
Check whether there is no
dust around the drain pump
intake.
3) Check for clogged drain pipe
Check whether there is no
clogging outside of the pipe
body.
4) Check for return water.
Pour approximately 1-liter water
in the drain pump, and start the
drain pump.
When the water level in the drain
pan becomes steadily lower, stop
the pump, and check the amount
of the return water to the drain
pan.
*When a large amount of water
returns, the gradient of drain
pipe may be the reason.Check
whether the drain pipe is in-
stalled properly as the instruc-
tions in the installation manual
say.Furthermore, check wheth-
er the gradient of the unit instal-
lation is horizontal.An error may
occur due to return water de-
pending on the gradient.
Target gradient approximately
0.5°)
After checking the above, when all
normal, misdetection of the drain
sensor is possible.
Check the drain sensor.
Check the resistance value
<Error reset method>
Reset (error reset) the indoor unit in
trouble with the remote controller.
Same as above
<Error reset method>
Reset the power of the indoor unit in trou-
ble.However, the reset with the remote con-
troller (error reset) must be made 10
minutes later after the power has been re-
set.All the indoor units must be reset with
the remote controller.