18-BC97D1-1D-EN
15
Table 21. Defrost Control
Defrost controls have a selectable termination temperature. As
shipped, defrost will terminate at 47°F. for higher termination
temperature, cut Jumper J2 to achieve 70°F. See Service Facts
shipped in the outdoor unit for more information.
Pin Identificationon J5 (See Illustration)
1. TEST_COMMON (Shorting to FRC_DFT causes the control to
initiate Forced Defrost. Leaving this pin open results in the
normal mode of operation).
2. 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:
• Status LED on board flashing 1 time/second in standby or 2
times/second with call for heating or cooling.
• 24V AC between R&B
• 24V AC between Y, Y0, & 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.
EElleeccttrriiccaall —— LLooww VVoollttaaggee
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