DCN: 141-00940-09 11/02/07
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out. This delay is to allow the compressor head pressure to bleed off before starting again. In addition, at
the end of every heating or cooling call the MOT is triggered to prevent rapid cycling of the system.
NOTE: The Status LED on the Control Unit circuit board will change to flash twice to indicate the
system is in a MRT or MOT delay period.
Standard HVAC System Setup
Standard System Mode Selection
. To set the Control Unit for standard GAS/ELECTRIC operation, set
the dipswitch SW1 position 1 to the STD SYS position (SW1-1 = OFF).
Fan Mode Selection
. Normally, GAS heating systems DO NOT require fan calls along with the heat call
due to automatic fan operation in the furnace. For Gas systems, dipswitch SW1 position 2 should be set to
the STD FAN position (SW1-2 = OFF).
Electric and hydronic heating systems generally DO require that a fan call be generated along with the heat
call. For these systems, dipswitch SW1 position 2 should be set to the FAN/HEAT position (SW1-2 = ON).
Be sure to check your HVAC system’s requirements.
Note: Dipswitch SW1 position 3, the CO selection is not required for standard systems. Leave in the Off
position (SW1-3 = OFF)
TXB16 Control Unit HVAC System Outputs for Standard Systems
Operating Mode
Outputs (no Fan with Heat)
Outputs ( Fan with Heat)
Manual Fan
G
G
Heating Stage 1
W1
W1, G
Heating Stage 2
W1, W2
W1, W2, G
Cooling Stage 1
Y1, G
Y1, G
Cooling Stage 2
Y1, Y2, G
Y1, Y2, G
