Uf" Malfunction Of Transmission Between Indoor And Outdoor Unit / Piping And Wiring Mismatch / Gas Shortage - Daikin SkyAir Service Manual

SiBE28-804
5.40 "UF" Malfunction of Transmission between Indoor and
Outdoor Unit / Piping and Wiring Mismatch / Gas
Shortage
UF
Remote
Controller
Display
Applicable RZQ(S)71~140
Models
Method of Check the transmission between the indoor and outdoor units with a microcomputer when the
power turned ON.
Malfunction
Detect by checking the following temperature differences during compressor operation.
Detection
Malfunction When the inter-unit wiring between the indoor and outdoor units is incorrect
When the following conditions continue for 20 minutes during compressor operation
Decision
Conditions
Supposed
Causes
Troubleshooting
Troubleshooting
A: Difference in temperature detected by the indoor heat exchanger thermistor (R2T) and
the indoor suction air thermistor (R1T)
B: Difference in evaporation temperature (Te) (or condensation temperature (Tc) during
heating operation) detected by the indoor heat exchanger thermistor (R2T) and the
compressor sensor
A: R2T – R1T < 4ºC, and
B: R2T – Te (or Tc during heating operation) > 14ºC (24ºC during heating operation)
Faulty inter-unit wiring between the indoor and outdoor units
Mismatching of wiring and piping
Refrigerant shortage (out of gas)
Clogged refrigerant piping system
Be sure to turn off power switch before connect or disconnect connector,
Caution or parts damage may be occurred.
Does
"UF" appear when the
power is turned
ON?
NO
Is the
connection of inter-unit
wiring and piping between the
indoor and outdoor units
matched?
YES
(P236)
Check 13
Is the refrigerant
level proper?
YES
Troubleshooting by Remote Controller Display / LED Display
YES
The phase of inter-unit wiring
between the indoor and
outdoor units is incorrect.
NO
NO
Correctly connect
inter-unit wiring
between the indoor
and outdoor units.
Match the connection
of the inter-unit wiring
and piping between
the indoor and
outdoor units.
Recharge a proper
amount of refrigerant
after refrigerant
collection and vacuum
drying.
Check 8 (P232)
Check the refrigerant
piping system for
clogging.
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