Kees DFG (DIRECT FIRED GAS) MAKE-UP AIR UNITS - Manual (Page 9)

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13. REMOTE TEMPERATURE SELECTOR
The function of this dial is to set the desired discharge temperature the unit is to supply. This dial
working in conjunction with the discharge temperature sensor sends a D.C. voltage signal to the
amplifier that modulates the burner to a specific supply temperature.
14. ROOM SELECTRASTAT
The function of this room thermostat is to vary a D.C. voltage signal to the amplifier that will
modulate the burner to maintain a supply air temperature to satisfy space temperature.
15. CLOGGED FILTER SWITCH & LIGHT
The function of this control system is to sense by negative pressure a dirty filter condition and
signal that filter maintenance is required. With a negative pressure above the setting of the filter
switch (sensed on the leaving side of the filter), the switch will trip, energizing the filter light on the
remote control panel.
Set: A visual inspection should be made of the filters until the first cleaning is necessary. At this time
adjustment of the switch should be made. Turn switch adjustment clockwise until the switch
closes. After cleaning or replacing the filters, check to make sure the light is no longer lit.
16. TIME CLOCK
The function of this clock is to cycle the unit "ON" or "OFF" for a set time period during each 24
hour period on a constant running unit; or to cycle the unit from day to night for day/night
operating units. On day/night units, the remote control panel will have a time clock override
switch that can be used on the time "OFF" periods to switch the unit back on to constant running.
Set: Program the unit for the desired time "ON" and "OFF". Instructions are included with the time
clock.
17. PREPURGE TIMER
The function of this timer is to purge the combustion area and the discharge supply duct before
the burner flame safety circuit is energized.
Burner circuit power will energize the pre-purge timer. When the timed purging period is over,
the flame safety circuit will be energized.
Set: 1 minute.
18. AUDIBLE ALARM
The function of this alarm is to give an audible alarm signal down in the space, along with the
alarm light on the remote panel, when there is a burner flame failure.
On a flame failure, and after a 30 second safety timing period, the alarm contacts of the burner
control module will close. This will energize the flame failure light and the audible alarm. To
silence the alarm, the green reset button on the flame safety will need to be reset.