4. Be sure the gas control has been in the Off position for at
least 5 minutes before starting the furnace.
5. Move the gas control to the ON position.
NOTE: This furnace is equipped with an ignition device which
automatically lights the burner. This furnace cannot be lighted
manually. Do not try to light the burner by hand.
6. Turn on the electrical power to the furnace.
7. Set the room thermostat to a point above room temperature
to light the main burners.
8. Observe the pressure reading on the pressure gauge.
9. Refer to the Manifold Pressure vs. Altitude Chart for the
correct manifold pressure. If necessary, remove the regulator
adjusting burner box reference tap on the gas control valve
(has barbed fitting and hose on sealed combustion units) and
turn the regulator adjusting screw clockwise to increase
pressure and input, or counterclockwise to decrease pressure
IMPORTANT: If the manifold pressure cannot be adjusted to
the correct value, contact your gas supplier.
10. Move the gas control to the OFF position.
11. Disconnect the pressure gauge from the ¹⁄₈" (3.2 mm) NPT
outlet pressure tap.
12. Replace outlet pressure tap plug and the regulator adjusting
burner box reference tap (has barbed fitting and hose on
sealed combustion units) on the gas control valve.
13. Move the gas control to the ON position.
14. Replace the burner access door.
IMPORTANT: Do not use this furnace if any part has been under
water. Immediately call a qualified person to inspect the furnace
and to replace any part of the control system and gas control
which has been under water.
1. Be sure you have all of your tools.
2. Dispose of/recycle all packaging materials.
3. Check the furnace in its final location. Be sure the vent is not
Measure Temperature Rise
1. Adjust the room thermostat to the highest temperature
2. After 20 minutes of heating operation, measure the furnace
temperature rise. Take air temperature readings in both the
return air ducts and the heated air ducts (about 6 ft from the
furnace where they will not be affected by radiant heat) as
NOTE: If more than one run of return or heated air ducts is
used, air temperature measurements should be taken in each
duct. These measurements can be converted to an average
to obtain the temperature rise of the whole system.
15. Set the room thermostat to the desired temperature
necessary to achieve optimum temperature rise.
Manifold Pressure vs. Altitude Chart for Natural Gas
For Altitudes 7,500 to 10,000 ft (2,286 m to 3,048 m)
Above Sea Level
Do not adjust manifold pressure. An orifice change is required.
For the correct orifice size, see Table F.4 in Appendix F of the
National Fuel Gas Code (ANSI Z223.1/NFPA 54, latest edition).
A. Measure return air here.
B. Warm air
3. If furnace doesn't maintain temperature rise within the range
shown on the furnace rating plate, adjust the blower speed.
C. Measure supply temperature here.
D. Return air