56
Gas Heater Startup
1. Turn thermostat or temperature controller
to its lowest setting.
2. Turn off gas supply at the manual shut-off
valve (supplied by others).
3. Turn off power to the unit at the disconnect
switch.
4. This appliance is equipped with an ignition
device which automatically lights the burner.
Do NOT try to light the burner by hand.
5. Open door to unit module housing the gas
heater.
6. Move gas control switch to “OFF”
position.
Figure 38 - Gas Control Switch
7. Install a tapped fitting for attachment to a
manometer or other gauge suitable for
14.0”wc in the inlet pressure tap. Install a
tapped fitting for attachment to a manometer
or other gauge suitable for 10.0”wc in the
manifold pressure tap.
8. Wait 5 minutes for any gas to clear out. If
you smell gas, turn off gas supply at the
manual shut-off valve (field installed). If you
don’t smell gas or have corrected any leaks,
go to the next step.
9. Turn gas control switch to “ON” position.
10. Close door to unit module housing the gas
heater.
11. Open all manual gas valves (supplied by
others).
12. Turn power on at disconnect switch.
13. Set thermostat or controller to its highest
position to initiate call for heat and maintain
operation of unit.
14. Draft inducer will run for a 5 second pre-
purge period.
15. The control energizes the spark and main
gas valve for a 20 second ignition period.
16. The control shuts spark off and waits for
a 30 second heat blower on delay period and
then energizes the indoor blower heat speed.
17.
Control
inputs
are
continuously
monitored to ensure limit and pressure
switches are closed, flame is established, and
the thermostat call for heat remains.
18. Inlet gas pressure should be between 6.0”
and 14.0”wc on Natural Gas (11.0” to
13.0”wc on Propane). Adjust supply
regulator if necessary or contact utility if
unable to obtain proper inlet pressure.
19. At burner ignition, manifold pressure will
be 1.7”wc. Furnace will continue at this input
rating for 90 seconds.
20. All control systems require a manifold
pressure of 3.50”wc at maximum input (high
fire) on Natural Gas, and 10.5”wc on Propane
Gas V3-A & V3-B (10.0”wc for V3-C).
21. Systems with modulating gas heat require
a manifold pressure of 0.40”wc at 33%
turndown on Natural Gas.
Failure to Ignite
1. For the initial start-up, or after unit has
been off long periods of time, the first
ignition trial may be unsuccessful due to need
to purge air from manifold at start-up.
