OPERATING INSTRUCTIONS
CAUTION: This furnace is equipped with an intermittent pilot
and automatic re-ignition system. DO NOT attempt
to manually light the pilot.
TO LIGHT PILOT AND MAIN BURNERS:
1. Turn “off” electric power to unit.
2. Turn room thermostat to lowest setting.
3. Turn gas valve knob to “on” position.
4. Turn “on” electric power to unit.
5. Set room thermostat to desired temperature.
( I f t he r mo s ta t “s e t” te m pe ra tu re is ab o ve ro om
temperature, pilot burner ignition will occur and, after an
interval to prove pilot flame, main burners will ignite).
TO SHUT DOWN:
1. Turn “off” electric power to unit.
2. Depress knob of gas valve while turning to “off” position.
POST-START CHECK LIST (GAS)
After the entire control circuit has been energized and the
heating section is operating, make the following checks:
1. Check for gas leaks in the unit piping as well as the supply
piping.
2. Check for correct manifold gas pressures. See “Checking
Gas Input”.
3. Check the supply gas pressure. It must be within the limits
shown on rating nameplate. Supply pressure should be
checked with all gas appliances in the building at full fire.
At no time should the standby gas line pressure exceed 13",
nor the operating pressure drop below 5.0" for natural gas
units. If gas pressure is outside these limits, contact the
local gas utility for corrective action.
MANIFOLD GAS PRESSURE ADJUSTMENT
Small adjustments to the high-fire gas flow may be made by
turning the pressure regulator adjusting screw on the automatic
gas valve. Refer to Figure 15.
Adjust as follows:
1. Remove the cap on the regulator. It’s located next to the
push-on electrical terminals.
2. To decrease the gas pressure, turn the adjusting screw
counterclockwise.
3. To increase the gas pressure, turn the adjusting screw
clockwise.
NOTE: The correct manifold pressure for these furnaces is
3.65 IWG
±
0.3.
FIG 12-GAS VALVE AND CONTROLS
HEAT ANTICIPATOR SETPOINTS
It is important that the anticipator setpoint be correct. Too high
of a setting will result in longer heat cycles and a greater
temperature swing in the conditioned space. Reducing the
value below the correct setpoint will give shorter “ON” cycles
and may result in the lowering of the temperture within the
conditioned space.
PRE-START CHECK LIST
Complete the following checks before starting the unit.
1. Check the type of gas being supplied. Be sure that it is the
same as listed on the unit nameplate.
2. Make sure that the vent and combustion air hoods have
been properly installed.
Gas Valve
Anticipator Setpoint
1st Stage
2nd Stage
Honeywell VR8440
0.30 amp
0.11 amp
White-Rodgers 36C68
START-UP
ON-OFF CONTROL
HIGH FIRE ADJ.
(UNDER SCREW)
PILOT ADJ.
(UNDER SCREW)
FIG. 13 - TYPICAL GAS VALVE
530.18-N11Y
Unitary Products Group
17
