Forbottom (end) return installations, the above optional
external rack may be used, it" the unit was not provided with an
internal filter. Minimum filter size and suggested filter materials
are shown in Table 1.11: (If differant type filter is used, it must be
an equivalent high airflow capacity).
Table 1.11 FILTER SIZE SELECTION
B'IU FILTER SIZE END _g_
INPUT SIDE-RETURN RETURN
5"0.000 15 V1 X25 12X25
75.oooI
100.0(30 i 15 IA X 2.5 IS Vl X 25 t_arm din' na,ta t.=.
125.0001 15V2 X2.5 19X25
Here's How Your Heating System Works:
The furnace operates automatically. A thermostat that you set
at the temperature most comfortable to you controls it. When the
inside temperature drops below this setting, your thermostat will
turn on the heating system.
When the thermostat calls for heat, power from the
a'ansformer energizes the fan control board. The fan control
energizes the induced draft blower motor. The pressure switches
will close and inidate the ignition sequence. The SmartValve" will
energize the pilot gas valve. The SmartValve" will light the pilot
automatically. If the pilot flame is sensed, the main valve will
open and the pilot flame will light the burners.
The electronic fan control will automatically turn on the
blower after 30 seconds. Fan ON control is not adjustable. The air
moved over the heating element by the blower is warmed and
passes through the ducts to the room registers.
When the thermostat is satisfied, the circuit is de-energized
and the main gas valve stops gas flow to the burners. The blower
continues to run until the selectable fan OFF time period has
expired. (See Figure 2.14 for setting the desired fan OFF time.)
The heat-sensing switch performs as the high temperature
limit switch. If the furnace overheats for any reason, the limit
switch opens, breaking the circuit to the main gas valve. If the
limit is activated, check for a restriction in the duct system (i.e.,
dirty filters, blocked duct'work, closed registers, etc.). The blower
motor and inducer motor will be energized as the unit cools. As
soon as the limit switch closes the burners will relight, but unless
the overheating condition is corrected, the furnace will cycle on
limit. If the furnace is cycling on the limit switch corrective action
must be taken. Failure to correct this condition could possibly
damage the heat exchangers and may not be covered by the
walTanty.
WARNING
Should overheating occur, or the gas supply fail
to shut OFF, turn off the manual gas valve to the
appliance BEFORE turning off the electiical
supply. A failure to adhere to this warning can
result in a fire or explosion and bodily harm.
This furnace is equipped with a Honeywell SV9501 "Hob
Surface Pilot" ignition control. If the unit does not light due to a
gas interruption, the system will continue attempting to light until
the gas is restored and the unit lights or the system is turned
"OFF". The sequence of lighting is as follow:.
30 sec. Trial for ignition - igniter & pilot valve energizes
25 see. Lockout - igniter & pilot valve de-energized
30 sec. Trial for ignition - igniter & pilot valve energized
5 min. Lockout - igniter & pilot valve de-energized
As long as the thermostat is calling for heat this cycle will
repeat indefinitely until the pilot lights.
STARTUP AND OPERATIONAL CHECKOUT
WARNING
Do not use this furnace as a construction heater:
Use of this furnace as a construction heater
exposes the furnace to abnorma! conditions,
contaminated combustion air and the lack of air
f'tlters. Failure to follow this warning can lead to
premature furnace failure and/or vent failure
which could result in a fire hazard and/or bodily
harm.
The automatic gas valve controls the flow of gas to both the
pilot and main burners. The ignition system control switch built
into the automatic valve body has 2 positions: "OFF" and "ON"
(Figure 1.12). To shut off gas manually: Slide switch from "ON"
to "OFF" position. When in "OFF" position, the main bun_rs and
the pilot are extinguished.
This furnace is equipped with an automatic hot-surface pilot
ignition control and does not require the manual lighting of a pilot
for furnace operation.
20246506 Issue 9939 Page 11 of 22
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