Install Instructions

NOTICE
The gas valves are referenced to the fan
pressurized chamber by a hose connected
from the vent of the gas valve regulator
to the chamber pressure tap located on
the front inside portion of the jacket.
Reference the drawings in this section for
component and connection points for
pressure measurement. The referenced
chamber pressure must be subtracted from
the manifold pressure to obtain actual net
manifold pressure for normal operation.
A manometer or magnahelic gauge legible
in 0.1'' increments up to 10 inches w.c. is
required to check and adjust the manifold
pressure. The regulator cover screw on the
gas valve must be in place and tight for the
unit to operate properly.
27
3 Gas connections (continued)
10. If gas supply pressure is within normal range, remove the
gas manometer and replace the pressure tap fittings in the
gas control as indicated by the following steps.
11. Turn power switch to the “OFF” position.
12. Turn gas valve knob to the “OFF” position.
13. Shut off gas supply at the manual gas cock in the gas piping
to the unit. If fuel supply is L.P. gas, shut off gas supply at
the tank.
14. Remove the manometer and related fittings from the “inlet
side of the gas valve, replace 1/8'' hex plug in the gas valve
and tighten.
15. Turn on the gas supply at the manual valve, turn on L.P. gas
at the tank if required.
16. Turn the power switch to the “ON” position.
17. Turn the gas valve knob to the “ON” position.
18. Set the electronic temperature control or thermostat to call
for heat.
⚠ WARNING
After completing any testing on the gas
system, leak test all gas connections. Apply
a soap/water solution to all gas connections
while main burners are operating. Bubbles
forming indicate a leak. Repair all leaks at
once. Do not operate this unit with a leak in
the gas train, valves or related piping.
Check burner performance by cycling the system while you
observe burner response. Burners should ignite promptly.
Flame pattern should be stable, see Burner Flames in the
Maintenance section of this manual. Turn system off and allow
burners to cool, then cycle burners again to ensure proper
ignition and flame characteristics.
INLET
GAS
VALVE
CONTROL
KNOB
OUTLET
SUPPLY INLET
PRESSURE TAP
Figure 3-3_Measuring gas supply pressure at combination
gas valve
Gas manifold pressure adjustment
1. Remove the thumbscrew that fastens the control panel
access door and remove the door.
2. Turn the power switch located in the lower left corner
behind the control panel access door to the “O” or “OFF”
position.
3. Remove the top front jacket access panels to access the gas
valve(s).
4. Locate the reference hose on the first gas valve which goes
from the vent fitting on the gas valve to the barbed fitting
on the deck of the unit (see FIG. 3-4).
5. Remove the flexible cap from the barbed fitting on the “tee”
located in this line and hook one side of the manometer, or
(-) side of a magnahelic gauge, to this “tee”. Retain this cap
for future use.
6. Remove the 1/8'' hex plug from the manifold pressure tap
on the gas valve (see FIG. 3-4). Retain plug for future use.
7. Install a fitting in this tap that is suitable for connection of
a hose to a manometer, or (+) side of a magnahelic gauge
(see FIG. 3-4).
8. Turn the power switch to the “I” or “ON” position.
9. Push the reset button(s) for the ignition control(s), if
necessary.
10. Set the temperature control to call for heat (see Setting
Temperature Control, page 41).
11. Once the unit is firing, the manometer/magnahelic will
reflect the net manifold gas pressure. Compare this reading
to the respective value in Table 3E for Natural Gas or
Propane Gas.
Installation & Service Manual