All installations and services must be performed by qualified service personnel.
6
Compressor contactor
The control provides switched 24VAC to operate a compressor contactor. Rating shall be class 2 - 24
VAC pilot duty @ 24 VAC (< 200mA).
EAC (electronic air cleaner)
The control provides a 120VAC output for an electronic air cleaner. This output is energized whenever the fan
motor is energized (either low, heat or cool speed). Connection is made via male quick connect terminal
labeled "EAC".
Humidifier
The control provides a 120 VAC output for a humidifier. Connections are made to a male quick connect
terminal labeled "FAN". The control does not switch this output, it provides a pass-through connection from
P1-7 from the switched primary voltage of the Burner Module. In this application, the humidifier will operate
on any blower operation. Humidifier should be controlled by humidistat to prevent operation during cooling
fan operation.
Status LED
A red LED is provided to indicate any thermostat input has been recognized by the microprocessor on the
control. See Diagnostic Features for a function description of operation.
Thermostat Input LEDs
Four green LEDs are placed beneath their respective thermostat connections (W, Y, G and DEHUM) and
operate whenever a call is present. See Diagnostic Features for a function description of operation.
Motor CFM LED
This green LED will flash once for every 100CFM the blower is producing.
E. Operating Modes
Standby Mode
All outputs are off and the control is waiting for a thermostat demand. The thermostat inputs, and limit
switch are continuously monitored. The control initiates action when a thermostat call is received or limit
switch opens.
Fan Mode
A call for fan ("G") is received from the thermostat. If no other mode is calling for blower operation, the
control will choose a “Low” speed value from the position of DIP switch SW1 positions 4 through 6, as
shown in the CFM Tables and operate the fan at that speed. The fan mode will be operated as long as the
"G" input is calling
and neither the Heat mode nor the Cool mode is calling for blower operation. When the
Heat and Cool modes call for blower operation, their respective outputs will take over after their respective
turn-on time delays have expired. The speed Output is present until the fan call is satisfied.
Cooling Mode
A call for cool ("Y") is received from the thermostat. If the heat mode is not active or the anti-short cycle
delay is not in effect, the control will energize the “CC” terminal. After a 10 second delay blower ramps up to
the “COOL” speed determined by the position of DIP switch SW1 (positions 4 through 6) determine a speed as
shown in CFM Tables.
When the call for cool is satisfied, the “CC” terminal is de-energized and the cooling off delay of 45 seconds is
started. Forty-five seconds later the blower speed ramps toward zero and the control reverts to Standby Mode.
Summary of Contents for OH16-125
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