Lochinvar 90 3Gas connections continued, Gas Manifold Pressure Adjustment Procedure, 2_Wrench

3Gas connections (continued)

	WHEN FLANGE
	IS USED
	WHEN FLANGE
APPLY WRENCH	IS NOT USED
TO FLANGE ONLY

APPLY WRENCH FROM

BOTTOM OF GAS CONTROL

TO EITHER SHADED AREA

Figure 3-2_Wrench

8.For L.P. gas, consult your L.P. gas supplier for expert installation.

Installation & Service Manual

1.	Turn the power “OFF” at the main disconnect switch.
2.	Turn gas valve control knob to “PILOT” position on
	standing pilot models. Ensure that the standing pilot
	remains on. If the pilot goes out, follow the “Lighting
	Instructions” in Section 6 - Startup for standing pilot
	models to light the pilot. Turn gas valve control knob to
	“OFF” position on spark ignition models.
3.	Remove the 1/8" hex plug located on the outlet side of the
	gas valve and install a fitting suitable to connect to a
	manometer or magnahelic gauge. See FIG. 3-3. Minimum
	range of scale should be up to 5" w.c. for Natural gas
	models and 10" w.c. for L.P. gas models.
4.	The 500,000 Btu/hr model will have two gas valves with a
	pressure regulator on each valve. Repeat the following
	adjustment procedure to set the manifold pressure on each
	gas valve.
5.	Remove the pressure regulator adjustment cap screw on

IMPORTANT

Upon completion of any piping connections to the gas system, leak test all gas connections with a soap solution while system is under pressure. Immediately repair any leaks found in the gas train or related components. Do Not operate an appliance with a leak in the gas train, valves or related piping.

	the gas valve. See FIG. 3-3 for location.
6.	Turn the power “ON” at the main disconnect switch.
7.	Turn gas valve control knob to “ON” position.
8.	Set the thermostat(s) to call for heat.
9.	Observe gas regulator pressure when all burners are firing.
	See Table 3B, Manifold Pressure (page 19) for proper
	regulator pressure settings.

Gas Manifold Pressure Adjustment Procedure

10. If adjustment is necessary, turn regulator adjustment screw

clockwise to raise regulator gas pressure, counterclockwise

INLET

PRESSURE

TAP

MANOMETER

PRESSURE REGULATOR

ADJUSTMENT

(UNDER SCREW CAP)

OUTLET

PRESSURE TAP

PILOT OUTLET

GAS CONTROL KNOB

RED RESET BUTTON

to lower gas pressure, to proper setting. NOTE: Adjustment

fitting is plastic and may require slightly greater turning

force than a metal fitting.

11. Turn the power “OFF” at the main disconnect switch.

NOTICE	Do not increase regulator pressure beyond
	specified pressure setting.

12.	Turn gas valve control knob to “PILOT” position on
	standing pilot models. Turn gas valve control knob to
	“OFF” position on spark ignition models.
13.	Remove fitting from the gas valve and replace the 1/8" hex
	plug that was previously removed and tighten.
14.	Repeat the adjustment procedure for the second gas valve
	on the 500,000 Btu/hr model.
15.	Turn the gas valve control knob(s) to “ON” position.
16.	Turn the power “ON” at the main disconnect switch. The

UNION

GAS VALVE

Figure 3-3_Manifold Pressure Adjustment

appliance is now ready to operate.

If manifold pressure can not be properly adjusted, use the procedure on page 22 to check gas supply pressure with a manometer connected to the inlet pressure tap on the gas control.

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