Service Manual

14
C. Control Board Check
Before replacing a CB that does not show a visible defect and that you suspect is bad,
always conduct the following check procedure. This procedure will help you verify your
diagnosis. Before proceeding, check for proper voltage per appliance nameplate. Check
that the 24VAC 1A fuse is good and 115VAC 3A GM external protector is closed.
NOTICE! Control Board Change:
• "F-A" control board 2A4296-01 no longer available.
• "F-C" control board 2A8054-01 new and replaces 2A4296-01.
• Check the S1 dip switch settings to assure that they are in the factory default position.
For factory default settings, see "III.C.1. Default Dip Switch Settings." S1 dip switch
7determines bin control application. WARNING! Do not adjust S1 dip switch 4, 7, 8,
or 9 dip switches out of their factory default positions. These dip switches must
be left in the factory default position or the appliance will not operate correctly.
• When checking for 115VAC high-voltage (primary), always choose a 115VAC
neutral(W) to establish a good neutral connection.
• When checking for 24VAC low-voltage (secondary), always choose a 24VAC
neutral(LBU) to establish a good neutral connection. If the appliance is in alarm, see
"III.B. LED Lights and Audible Alarm Safeties."
• When checking for 5VDC, use CBred K4 connector pin closest to CB black
K3connector for DC ground (GND).