Section 12. Electrical - High Voltage - Trane 4TWR4 Installation And Operation Manual

11.3 Defrost Control - 036 Model ONLY
Defrost controls have a selectable termination temperature. As shipped, defrost will terminate at 47°F. For a
higher termination temperature, cut Jumper J2 to achieve 70°F when at or below 30°F ambient. See Service
Facts shipped in the outdoor unit for more information.
Pin Identification (See Illustration at right)
1. TEST_COMMON (Shorting any of the other pins to this pin causes the function of the other pin to be
executed. Leaving this pin open results in the normal mode of operation.)
2. TST = Test (Shorting TEST_COMMON to this pin speeds up all defrost board timings.)
3. FRC_DFT = Forced Defrost (Short TEST_COMMON to this pin for two (2) seconds to initiate a forced
defrost. Remove the short after defrost initiates.)
Defrost Control Checkout
Normal operation requires:
•
LED on board flashing 1 time/second.
•
24V AC between R & B.
•
24V AC between Y & B with unit operating.
•
Defrost initiation when FRC_DFT pin is shorted to TEST_COMMON pin.
If a defrost control problem is suspected, refer to the service information in control box.
Defrost Termination Temperatures
Outdoor
Temperature
>22°F
As
Shipped
10°F–22°F
6°F–10°F
Cut >30°F
Jumper 2
6°F–30°F
All < 6°F

Section 12. Electrical - High Voltage

12.1 High Voltage Power Supply
! WARNING
LIVE ELECTRICAL COMPONENTS!
During installation, testing, servicing, and
troubleshooting of this product, it may be nec-
essary to work with live electrical components.
Failure to follow all electrical safety precau-
tions when exposed to live electrical compo-
nents could result in death or serious injury.
The high voltage power supply must agree with
the equipment nameplate.
Power wiring must comply with national, state,
and local codes.
Follow instructions on unit wiring diagram located
on the inside of the control box cover and in the
Service Facts document included with the unit.
18-BC95D1-5E-EN
Termination
Temperature
47°F
ODT + 25°F
35°F
47°F
70°F
12 min. or 35°F
every 3 hrs.
Defrost Board
Detail
JUMPER 2
TEST PINS
J1
J2
J3
U1
FRC_DFT
TST
11