Lochinvar 402 - 2072 Relief valve, Heating boiler installations, Piping of the boiler system

4 Water connections (continued)

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.

Heating boiler installations

Piping of the boiler system

The drawings in this section show typical boiler piping installations, see FIG.’s 4-3 through 4-6. 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.

Water connections (heating boilers only)

Models 402 - 752 have 2" NPT inlet and outlet connections and Models 992 - 2072 have 2 1/2" NPT inlet and outlet connections.

￿ CAUTION	Field installed reducing bushings must not
	be used.

Installation & Operation Manual

Any reduction in pipe size may decrease flow resulting in high water temperatures, boiler noise, flashing to steam, and non- warrantable heat exchanger damage.

The boiler may be installed with a primary/secondary piping system provided to the boiler. It is important to guarantee that adequate flow is provided to properly dissipate heat from the boiler and also ensure that flow through the boiler does not exceed the maximum recommended flow rate of 55 GPM for Models 402 - 752 and 90 GPM for Models 992 - 2072 for a boiler equipped with a copper heat exchanger.

Boiler circulator requirements

This is a low mass, high efficiency hot water boiler which must have adequate flow for quiet, efficient operation. Pump selection is critical to achieve proper operation. A pump should be selected to achieve proper system design water temperature rise. Pipe diameter and length are critical to ensure proper flow through the boiler. A System Temperature Rise Chart (Table 4C on page 38) is provided to assist in proper pump selection. This table provides GPM and boiler head-loss at various temperature rises for each model based on Btu/hr input. Temperature rise is the difference in boiler inlet temperature and boiler outlet temperature while the boiler is firing at full rate.

Example: The boiler inlet temperature is 160°F (71.1°C) and the boiler outlet temperature is 180°F (82.2°C). This means that there is a 20°F (11.1°C) temperature rise across the boiler. The boiler temperature rise is visible in the Operator Interface on the boiler’s front control panel.

Circulator pump specifications

1.Maximum operating pressure for the pump must exceed system operating pressure.

2.Maximum water temperature should not exceed the nameplate rating.

3.Cast iron circulators may be used for closed loop systems.

4.A properly sized expansion tank must be installed near the boiler and on the suction side of the pump.

Circulator pump operation (heating boilers only)

The boiler pump must run when the boiler is firing. Separate supply circuits can be provided or the two circuits (pump and controls) can be combined for connection to one circuit, properly sized for both.

Pump delay operation

A pump delay operation feature is provided. The boiler’s circulating pump will cycle on at each call for heat, before the burner fires. The pump will continue to operate while the burner is firing. The pump will run for a 30 second period after the temperature set point is satisfied. This timing is selectable from the Operator Interface. This timing will remove any of the residual heat from the combustion chamber before turning the pump off. See the wiring diagram in Section 9 of this manual.

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