Checking Gas Supply Pressure - Lochinvar EW150 Installation & Service Manual

3
Gas connections
If the regulator cover screw it not in
NOTE
place and tight, the appliance will not
function properly.
20. Turn the power switch to the "OFF" position.
21. Turn gas valves and manual gas cock knob to the "OFF"
position.
22. Remove the gas pressure fitting from the gas valve and
replace with the 1/8" hex plug (that was previously
removed) and tighten.
23. Ensure that the chamber pressure reference hose is
properly connected to the gas valve.
24. Turn the gas valve knobs to the "ON" position.
25. Turn the power switch to the "ON" position and replace
the jacket panel. The appliance is now ready to operate.
If manifold pressure cannot be properly maintained, check
gas supply pressure with a manometer connected to the
inlet pressure tap on the gas control.
Figure 3-5 Manometer Connection for Gas Supply
Pressure Measurement
MANOMETER

Checking gas supply pressure

1. Turn the power switch and thermostat to "OFF"
position.
2. Turn gas valve knob to "OFF" position.
3. Shut off gas supply at the manual valve in the gas piping
to the appliance. If fuel supply is LP gas, shut off gas
supply at the tank.
4. Remove the 1/8" hex plug, located on "inlet" side of the
gas valve and install a fitting suitable to connect to a
manometer or magnahelic gauge. Range of scale should
be 14" w.c. or greater to check inlet pressure.
5. Turn on gas supply at the manual valve, turn on LP gas
at tank if required.
(continued)
GAS VALVE
Installation & Service Manual
6. Turn the power switch to "ON" position
7. Turn the gas valve knob to "ON" position
8. Set the thermostat to call for heat.
9. Observe the gas supply pressure as the burners are firing.
Ensure inlet pressure is within specified range.
10. If gas pressure is out of range, contact gas utility,
gas supplier, qualified installer or service agency to
determine necessary steps to provide proper gas pressure
to the control.
11. If gas supply pressure is within normal range, proceed to
remove gas manometer and replace pressure tap fittings
in the gas control.
TABLE 3G - MINIMUM AND MAXIMUM GAS
SUPPLY PRESSURES
Maximum Inches (water column)
Minimum Inches (water column)
12. Turn the power switch and thermostat to "OFF" position.
13. Turn gas valve knob to "OFF" position.
14. Shut off gas supply at the manual valve in the gas piping
to the appliance. If fuel supply is LP gas, shut off gas
supply at the tank.
15. Remove the manometer and related fittings from "inlet"
side of the gas valve, replace 1/8" hex plug in gas valve.
16. Turn on gas supply at the manual valve, turn on LP gas
at tank if required.
17. Turn the power switch to "ON" position.
18. Turn the gas valve knob to "ON" position.
19. Set the thermostat to call for heat.
Upon completion of any testing on the
IMPORTANT
gas system, leak test all connections
with a soap solution while main burners
are operating. Immediately repair any
leak found in the gas train or related
components. Do NOT operate an
appliance 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 "Maintenance-Normal
Flame Pattern." Turn system off and allow burners to cool,
then cycle burners again to ensure proper ignition and flame
characteristics.
Natural
LPG
Gas
10.5" w.c. 13" w.c.
4.0" w.c. 8" w.c.
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