20
Boss DF Construction Heaters
D. Selector Switch (Heat/Off/Vent)
This allows the end user to Heat, shut the heater OFF,
or to run fan only (Vent)
HEAT
position: fan motor and burner operate. The
thermostat cycles the heater ON and OFF automati-
cally.
VENT
position: fan motor ONLY operates. This
feature is used to circulate air if needed. VENT is not
operated by the thermostat. Manually reposition the
switch to OFF or HEAT.
FIG.15
E
D
F
E. Circuit Breaker (manual reset)
This protects an electrical circuit from damage caused
by overcurrent, typically resulting from an overload or
short circuit. Its basic function is to interrupt current
fl ow after a fault is detected preventing damage to
other electrical components, such as the circuit board.
If the breaker trips, its button needs to be manually
reset to close the circuit.
F. Voltage Meter
The identifi es if proper voltage is supplied to the
heater during operation. Observe the voltage indica-
tor during start-up and operation to ensure the heater
is receiving the proper voltage (120 VAC) during
operation. Poor voltage will cause heater malfunction.
G. Red Status Light
• The light will be constantly on during normal heating
operation.
• It will not be on when the switch is in vent mode.
Owner's Manual • Boss DF
G
• The red light will fl ash if a problem occurs. Count the
number of times it fl ashes & refer to Troubleshooting in
the manual.
H. Thermostat
The thermostat is a NEMA 4X, fully enclosed control of
single stage design with a 3°F / -16°C temperature
differential. The thermostat operates ONLY the heating
cycle. The thermostat can be checked by:
1. Remove the cover from the thermostat.
2. Set your volt meter to AC volts and refer to wiring
diagram on inside of cover.
3. Plug the heater in and set the selector switch to heat.
4. Check for 120 VAC to the incoming power terminal LINE
(L1) to ground.
5. If present, turn up the thermostat and check for 120 VAC
from the return (Heating) terminal to ground.
6. If 120 VAC is delivered to the thermostat but voltage is
not going out, the thermostat is defective.
Note: an alternate method is checking for ohms between
both L1 and Heating terminals. A reading of 1 ohm
indicates contact closure. A reading of OL indicates a failed
thermostat.
FIG.16
HEATING
LINE IN