OWNER’S MANUAL MODEL: 8745 TUCSON Vent-Free HEATER
-17-
INITIAL ADJUSTMENTS
Variable Output Control
The gas control valve is equipped with a variable
output control. This control varies the
rate
of heat
produced by the unit by varying the gas pressure to
the main burner tube. The
length
of the burn cycle
is affected by a combination of heat output and the
thermostat setting. If your stove cycles on and off
often, try, first, reducing the burn cycle by turning
the
HI/LOW
knob, on the control valve to a lower
setting.
Using the variable output control, the heat output of
the unit can be reduced for mild fall and spring
months, or maximized for the colder winter months.
This adjustment can be made by the homeowner as
necessary by turning the variable output control
knob to
“HI”, “LO”,
or any setting in between.
Air Shutter
The air shutter is preset by the manufacturer for
optimum operation and should not be adjusted by
the owner. The air shutter is used to regulate the
air-to-gas combustion mixture which in turn
influences the size and color of the flames.
Pilot Adjustment
The pilot light is preset by the manufacturer and
should not need adjustment. The pilot light flame
should be large enough to engulf the thermopile
and, on a NG assembly, the thermocouple as well
(located next to the pilot), but not so large as to
create excessive noise or consume excessive gas.
However, it can be adjusted by means of the pilot
light adjustment screw located on the gas control
valve. Open valve door to access the pilot
adjustment
screw. Refer to
# 3
of
Figure 5
to
determine the location of the pilot adjustment
screw.
Note that the pilot flame must engulf the thermopile
so that the thermopile can generate sufficient milli-
voltage (325 to 750mv) to power the millivolt gas
control valve. The flame on the pilot should look
like
Figure 9.
Controlling the Tucson by the wall
mounted thermostat may become erratic,
nonexistent, or the unit may go out, if the pilot light
flame is too small or misdirected away from the
thermopile.
Figure 9
DAILY OPERATION
Daily Operation
The Tucson gas-fired heater is easily operated by
the homeowner once installed and adjusted by
qualified service personnel. The unit is controlled
via the wall-mounted thermostat during the heating
season. Set the thermostat to the desired room
temperature and the unit will cycle on and off as
required. By adjusting the variable output control,
located on the gas control valve, the rate of heat
output can be varied to meet the heating
requirements of the season. Choosing a low flame
setting will result in longer burn cycles at a reduced
output, while choosing a high flame setting will
result in a shorter, hotter burn cycle.
