A
M-TRAC1
IOM-55
May 2019
10
(reason for the lockout) will be lost. When power is resumed the M-TRAC1 will remain locked
out, but only green LED flashing irregularly.
CONTROL
SYSTEM TIMING
Damper opening delay: Depends on type of damper actuator used.
Blower startup: 54 seconds after terminal FS is energized.
Low Limit bypass: 4.5 minutes from initial startup, 50 seconds nuisance timer.
Trial for ignition: 30 sec.
DISCHARGE AIR SETPOINT
The M-TRAC1 is a discharge air temperature controller with a built in face mounted set point
knob (that is activated by connecting terminal S to SP). Optionally, the M-TRAC1 is available
with a remote set point, with varying set point ranges. When a remote setpoint is provided, the
M-TRAC1 face mounted set point will have no effect.
Additional methods of resetting the discharge air temperature setpoint may be used. Refer to
the unit function and electrical drawing.
DISCHARGE AIR SENSOR
The M-TRAC1 is designed to use either a single or dual discharge sensors, wired in series. Dual
sensors are always used in equipment with temperature rise over 100˚F (55°C) or with dual
fans. In most applications the discharge air sensor(s) is located in the supply blower outlet.
The discharge air sensor also serves as a low limit (or freeze protection) sensor. The part
number of the sensor is noted on the electrical drawing.
The M-TRAC1 automatically checks the discharge air sensor(s). If the M-TRAC1 reads an open
sensor it will disable temperature control and reduce the firing rate to low fire, then shutdown
the appliance. Open sensor checking may be disabled by switching on DIP switch #4.
LOW LIMIT
The M-TRAC1 control is typically configured so that the discharge air temperature sensor also
performs the function of a low limit or freeze stat. If DIP switch 3 is ‘off’ the low limit function
is enabled. If the discharge temperature falls below 40˚F (4°C) the appliance will shut down and
the LED for low discharge temperature will begin flashing. On initial startup the M-TRAC1 will
internally bypass the low limit for 3 minutes. After this time, the low limit discharge
temperature must be below the low limit setpoint (40°F / 4°C) for 50 seconds before the
M-TRAC1 will shut the appliance off.
If DIP switch 3 is ‘on’, the low limit safety function is disabled.
