Trane 4TWL6036A1000A Service Facts Download Page 12

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4TWL6036A-SF-1F-EN

Table 3. LED FAULT CODES (continued)

LED

FAULT

CODES

FAULT DESCRIPTION

DEFROST

CONTROL

BEHAVIOR

5 FLASH

Soft Lock Out

5 flash goes away
after soft lockout
period expires. See
Note 2.

6 FLASH

Defrost cycles too close
together

Heating short cycle
fault triggers 6 flash.
The system will follow
10 adaptive time
heating cycles and
then return to
demand defrost.

9 FLASH

Low Ambient Soft Lockout.
Outdoor temperature
dropped below 3°F. (OFF at
-12°F/ON at 3°F)

Outdoor temperature
is below -12°F. See
Note 5.

1. Initiate Adaptive/Timed Limp Mode 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 strategy called

“Adaptive Limp Mode”. Adaptive limp mode is
defined as a timed heating mode following rapid
defrosts (accumulated heating times between
defrost totaling less than 15 minutes). Once invoked
the DFC will limit defrost periods and maximize
heating capacity. While in adaptive limp mode the
DFC will monitor heating and defrost periods for no
longer than 10 cycles. The DFC will then release the
board to demand defrost; however, if the LPCO
trips while in limp mode the system will initiate a
soft lockout and exit limp mode.

If both Coil Temp Sensor and Ambient Temp
Sensor have failed, initiate a 5 minute forced
defrost every 60 minutes of run time. This in
conjunction with the normal low pressure trip, will
initiate a soft lockout.

a. A short heating cycle that enters defrost in 15

minutes or less and/or enters two more defrosts
with less than 15 minutes of accumulative run
time each will enter an Adaptive Limp Mode (6
Flash).

b. Coil sensor failure will initiate a Timed Limp

Mode. This will be accompanied by a 2 flash.
The DFC will initiate defrost after 60 minutes of
accumulated heating runtime and terminate
after a 5 minute defrost. The limp mode will
clear after the sensor fault is cleared.

c. Ambient sensor failure will initiate an Adaptive

Timed Limp Mode. This will be accompanied by
a 1 flash. The DFC will initiate defrost after 60
minutes of accumulated heating runtime and
force a defrost, which will terminate on coil

temp. The limp mode will clear after the sensor
fault is cleared.

d. This could be caused by a condenser fan motor

failure, low charge or other reasons.

3. The first 15 minute soft lockout the system will

return to normal operation. Should this continue to
operate 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 4 flash will be
announced and system operation is interrupted. If
the ambient temperature climbs above 40°F for
more than 30 minutes this clears this fault count
and resumes normal operation.

a. If or when normal operation is restored after the

ambient temperature climbs above 40°F for
more than 30 minutes and another LP trip is
monitored on the 9th trip this will initiate a hard
lockout that will not be cleared by temperature
or time.

4. Once ambient drops to -12 or lower wait 5 minutes

before soft lockout begins. During soft lockout the Y
signal passes through to the X2 output. Resume
operation when ambient temperature rises to -3°F
or higher and after 5 minute soft lockout period
expires. LPCO should reset around 5°F.

5. During a Hard Lockout, the X2 relay opens so that

the Y signal d

ess n

ott pass through.

LPCO

HEATING Mode

Flash

Code

Trip

15 minute soft lock-out

period

5 and 6 flash