Trane 4WCC4024E1000A Installation And Operation Manual Download Page 24

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18-BB41D1-1A-EN

Table 14.

LED Fault Codes

LED

FAULT

CODES

FAULT

DESCRIPTION

DEFROST CONTROL

BEHAVIOR

1 FLASH

Ambient Temp Sensor is

out of range (open/

shorted)

Initiate a 15 minute forced

Defrost after every 60

minutes of runtime. See

Note 1 & 2

2 FLASH

Coil Temp Sensor is out

of range (open/shorted)

Initiate a 15 minute forced

Defrost after every 60

minutes of runtime. See

Note 2

3 FLASH

Low Pressure Switch is

open

3 flash goes away when/if

LPCO closes

4 FLASH

Hard Lock Out (can only

be cleared with power

cycle)

Occurs after 9th trip of

LPCO. Note 6

5 FLASH Soft Lock Out

5 flash goes away after soft

lockout periods expires. See

Note 2

6 FLASH

Defrost cycles too close

together

Heating Short Cycle Fault

triggers 6 flash & 5 flash

codes. Follow Soft Lock-out

sequence until Hard Lock-

out (4 flash) or can clear if

conditions no longer exist

7 FLASH

In Timed Defrost mode.

Check Ambient sensor

placement and verify

SOV is operating

properly.

Implied sensor fault

(calibration/range) set after

defrost and reset after 15

minutes run time after

defrost. See Note 4

8 FLASH

In Timed Defrost mode.

Check Coil sensor

placement and verify

SOV is operating

properly.

Outdoor temperature is

below -7° F. See Note 5.

9 FLASH

Low Ambient Soft Lock-

out Outdoor

temperature dropped

below 3°F. (OFF at -7° F/

ON at 3°F)

Outdoor temperature is

below -7° F. See Note 5.

1. Initiate Adaptive/Timed Defrost so long as Coil

Temp Sensor is functional. Monitor actual time in
defrost and add or reduce run time until next forced
defrost based on achieving a 4 minute (+/- 1) defrost
period.

2. This Defrost control utilizes a safety method called

“Inferred LPCO”. If both Coil Temp Sensor and
Ambient Temp Sensor have failed, initiate a 15
minute forced defrost after every 60 minutes of run
time. This is in conjunction with the normal Low
Pressure trip definitions. An “Inferred LPCO” trip is
defined as: A heating cycle that enters defrost in 15
minutes or less and then enters another defrost in
the same heating call within 15 minutes of the last
defrost call -does not complete a learning
algorithm. This could be caused by a condenser fan
motor failure or other reasons. The first soft lockout
occurs on the 4th defrost that was entered before

the learning routine could complete in the same
heating call. It is announced with a 5 flash and a 6
flash fault. After this first 15 minute soft lockout, the
system will return to normal operation. Should this
continue operating in this manner, there will be a 30
minute soft lockout and so on. At the end of the
lockout process, if a hard lock is necessary —a flash
will be announced and system operation is
interrupted. If the ambient temperature climbs
above 40 degrees F for more than 30 minutes, this
clears this fault count and resumes normal
operation.

3. Do not track if Y cycles off or if defrost takes 15

minutes (Max Time Override). Ambient Sensor
reading is monitored at the end of defrost and
should not deviate more than +/-5° F. Ambient
Sensor must report a lower temperature than the
Coil Sensor immediately after defrost (Coil Sensor
should always be higher than Ambient Sensor
when defrost terminates).

4. Do not track if Y cycles off or if defrost takes 15

minutes (Max Time Override). Coil Sensor reading
is monitored at the end of defrost and reading must
be less than Ambient Sensor after 15 minutes of run
time.

5. Once ambient drops to -7° F or lower, wait 5

minutes before soft lockout begins. During soft lock
out the Y signal passes through to the X2 output.
Resume operation when ambient temperature rises
to 3° F or higher and after a 15 minute soft lockout
period expires.

6. During Hard Lockout, the X2 relay opens so that the

Y signal does not pass through.

LPCO

Inferred

LPCO

HEATING Mode

Flash Code

1st Trip

15 minute soft lock-out period

5 and 6 flash

2nd Trip

30 minute soft lock-out period