Lochinvar 800 operation manual Gas Pressure, Gas valve replacement

7Gas connections

Installation & Operation Manual

￿WARNING

When re-tightening the set screw, be sure to tighten securely to prevent gas leaks.

Do not check for gas leaks with an open flame -- use the bubble test. Failure to use the bubble test or check for gas leaks can cause severe personal injury, death, or substantial property damage.

Figure 7-7Inlet Gas Supply Check - Models 600 - 800

REMOVE THE 1/8” (3 MM) PIPE PLUG ON THE INLET FLANGE TO THE VALVE AND INSTALL A SUITABLE 1/8” (3 MM) FITTING (FIELD SUPPLIED) FOR THE MANOMETER TUBING.

14.Turn on the gas supply at the manual gas valve.

15.Turn the power switch to the “ON” position.

16.Adjust the temperature set point on the control panel of the SMART SYSTEM control module to the desired water temperature so the appliance will call for heat.

17.Check burner performance by cycling the system while you observe burner response. The burner should ignite promptly. Flame pattern should be stable. Turn system off and allow burner to cool, then cycle burner again to ensure proper ignition and flame characteristics.

DETAIL

Figure 7-5Inlet Gas Supply Check - Model 399

LOOSEN THE SET SCREW ONE (1) FULL TURN

AND PLACE THE MANOMETER TUBING OVER

THE PRESSURE TAP.

Figure 7-6Inlet Gas Supply Check - Model 500

LOOSEN THE SET SCREW ONE (1) FULL TURN

AND PLACE THE MANOMETER TUBING OVER

THE PRESSURE TAP.

Gas Pressure

The gas pressure must remain between 4 inches w.c. (.99 kPa) minimum and 14 inches w.c. (3.5 kPa) maximum for Natural gas and between 8 inches w.c. (1.9 kPa) minimum and 14 inches w.c. (3.2 kPa) maximum for LP gas during standby (static) mode and while in operating (dynamic) mode. If an in-line regulator is used, it must be a minimum of 10 feet (3 m) from the Knight XL boiler. It is very important that the gas line is properly purged by the gas supplier or utility company. Failure to properly purge the lines or improper line sizing, will result in ignition failure.

The problem is especially noticeable in NEW LP installations and also in empty tank situations. This can also occur when a utility company shuts off service to an area to provide maintenance to their lines.

Gas valve replacement

The gas valve MUST NOT be replaced with a conventional gas valve under any circumstances. As an additional safety feature, this gas valve has a flanged connection to the venturi and blower.

DETAIL

￿WARNING

￿WARNING

Failure to follow all precautions could result in fire, explosion, or death!

DO NOT adjust or attempt to measure gas valve outlet pressure. Attempting to alter or measure the gas valve outlet pressure could result in damage to the valve, causing potential severe personal injury, death, or substantial property damage.

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