Harman Stove Company Hot Air s SF1500A - Manual (Page 11)

11
3-90-70744R11_05/13
duct work and Operating Instructions
duct work.
This figure shows a typical duct system
layout. Be sure the entire system is properly
sized to provide the correct static pressure
for optimum blower performance. Have
any new duct system designed by a HVAC
professional.
Operating Instructions
Adjusting Automatic draft Control - In
order for your new furnace to function, the
controls must be properly adjusted. The heat
output is regulated by the automatic draft
control, on the bottom door of the furnace.
Refer to the illustrations at right; The electric
draft motor (A) opens and closes the flapper
door (B). The flapper door opens to feed more air to the fire and closes to reduce the air to the
fire. The maximum air flow can be adjusted by turning the adjuster bolt (C) counter-clockwise
for more air and clockwise for less air. NOTE: To preserve motor life, all adjustments of this
bolt should be done while the flapper door is in the closed position. The idle adjuster (D)
controls the minimum amount of air that enters the firebox when the flapper door is closed.
Adjustment is made by turning the adjuster vertical for zero air, or horizontal for maximum
idle air. It is best to start at a medium setting as shown at right.
Adjusting the fan control- Shut off the power at the circuit breaker before removing the
fan control cover. Make sure the copper jumper (circled below) is removed before using the
furnace. Note the three pointers on the dial. The one on the right is the high limit adjustment.
Pre-set at 200 degrees, it’s function is to close the automatic draft control flapper door if the
temperature in the plenum reaches 200 degrees. do not change this setting. The center
pointer adjusts the temperature at which the blower starts. A good initial setting for this is
150 degrees. The pointer on the left is to adjust the temperature at which the blower stops. A good
initial setting for this pointer is 100 to 110 degrees. If it is set too low, the air will feel cool coming
out of the registers at the end of the blower cycle.
Thermostat- Set the thermostat to the desired temperature. When more
heat is needed, the thermostat opens the automatic draft control flapper
door. This allows air into the firebox, which raises the output of the fire.
When the temperature in the plenum reaches the set temperature of the
center pointer on the fan control, the blower will begin blowing heated
air through the ductwork. When the thermostat reaches it’s setpoint, the
automatic draft control closes the flapper door, thus, reducing the output
of the fire. As the temperature in the plenum drops to the set point of
the left pointer on the fan control, the blower will stop. A solid fuel fire
cannot cease output immediately, therefore, your room temperature
may exceed the thermostat setting at times. You also may notice times
that the blower runs for a short period even though the draft control
is closed. Again, you can’t just stop a wood or coal fire instantly, and
temperature may build enough to run the blower. This is normal and will
be noticed more with coal than with wood.
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return Air
Supply Trunk
Plenum
Figure 5
Figure 6
Figure 7