Lochinvar 497 - 2067 service manual Pressure Drop Chart, Water connections heating boilers only

4 Water connections

Water connections (heating boilers only)

Inlet and outlet water connections on Models 497 - 747 have 2'' NPT and on Models 987 - 2067 the inlet and outlet connections are 2 1/2'' NPT.

CAUTION	Field installed reducing bushings must not
	be used to reduce below the pipe diameters
	of the models listed above.

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 497 - 747 and 90 GPM for Models 987 - 2067 for a boiler equipped with a copper heat exchanger.

Installation & Service Manual

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

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 4B on page 30) 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.

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 minimum 30 second period after the temperature set point is satisfied. This timing will remove any of the residual heat from the combustion chamber before turning the pump off. See the wiring diagram in Section 10 of this manual.

Figure 4-3_Heat exchanger pressure drop chart_ Models 497- 747

Pressure Drop Chart

Models 497 - 747

HEAD	12
	10
FEETIN	8
DROP	6
	4
PRESSURE		20	30	40	45	50	55	60	65	70	75	80
	10
	2
	0

FLOW IN GALLONS PER MINUTE

Figure 4-4_Heat exchanger pressure drop chart_ Models 987 - 2067

MODELS 987 - 2067

28