Lochinvar 497 - 2067 service manual Water connections, Inlet and outlet connections, Relief valve

4 Water connections

Inlet and outlet connections

For ease of service, install unions on the water inlet and water outlet of the unit. The connection to the unit marked “Inlet” on the header should be used for return from the system. The connection on the header marked “Outlet” is to be connected to the supply side of the system.

Figure 4-1_Water Connections_Models 497 - 797

2" NPT WATER INLET

2" NPT WATER OUTLET

INSPECTION

PLUGS

Figure 4-2_Water Connections_Models 987 - 2067

2-1/2" NPT WATER INLET

2-1/2" NPT WATER OUTLET

INSPECTION

PLUGS

Relief valve

This unit is supplied with a relief valve(s) sized in accordance with ASME Boiler and Pressure Vessel Code, Section IV (“Heating Boilers”). The relief valve(s) is installed in the vertical position and mounted in the hot water outlet. No valve is to be placed between the relief valve and the unit. To prevent water damage, the discharge from the relief valve shall be piped to a suitable floor drain for disposal when relief occurs. No reducing couplings or other restrictions shall be installed in the discharge line. The discharge line shall allow complete drainage of the valve and line. Relief valves should be manually operated at least once a year.

CAUTION Avoid contact with hot discharge water.

Installation & Service Manual

Water flow switch

A water flow switch is factory installed in the outlet piping on all heating boilers and water heaters. The flow switch must prove water flow before a trial for ignition can begin. The flow switch requires a minimum flow of 15 - 18 GPM on Models 497 - 747 and 26 GPM on Models 987 - 2067 to make the flow switch and start burner operation. A water flow switch meets most code requirements for a low water cutoff device on boilers requiring forced circulation for operation.

Low water cutoff (if equipped)

If this boiler is installed above radiation level, a low water cutoff device must be installed at the time of boiler installation. An electronic low water cutoff is available as a factory supplied option on all models. The low water cutoff should be inspected every 6 months.

Heating boiler installations

Piping of the boiler system

The drawings in this section show typical boiler piping installations, see FIG.’s 4-5 through 4-8. Before beginning the installation, consult local codes for specific plumbing requirements. The installation should provide unions and valves at the inlet and outlet of the boiler so it can be isolated for service. An air separation device must be supplied in the installation piping to eliminate trapped air in the system. Locate a system air vent at the highest point in the system. The system must also have a properly sized expansion tank installed. Typically, an air charged diaphragm-type expansion tank is used. The expansion tank must be installed close to the boiler and on the suction side of the system pump to ensure proper operation.

CAUTION	The boiler system should not be operated at
	less than 12 PSIG.

Hot water piping must be supported by suitable hangers or floor stands, NOT by the boiler. Copper pipe systems will be subject to considerable expansion and contraction. Rigid pipe hangers could allow the pipe to slide in the hanger resulting in noise transmitted into the system. Padding is recommended on rigid hangers installed with a copper system. The boiler pressure relief valve must be piped to a suitable floor drain. See the Relief Valve section on this page.

CAUTION	A leak in a boiler “system” will cause the
	“system” to intake fresh water constantly,
	which will cause the tubes to accumulate a
	lime/scale build up. This will cause a non-
	warrantable failure.

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