Lochinvar 999 - 750, 399 Connecting To Electrical Supply, Relief Valve, Water Flow Switch

Installation and Service Manual

2-1/2" NPT

WATER OUTLET

2-1/2" NPT

WATER INLET

INSPECTION

PLUGS

FIG. 32 Water Connections

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. Place no other valve between the relief valve and the unit. To prevent water damage, pipe the discharge from the relief valve to a suitable floor drain for disposal when relief occurs. Do not install any reducing couplings or other restrictions in the discharge line. The discharge line will allow complete drainage of the valve and line. Manually operate the relief valves at least once a year.

CAUTION: Avoid contact with hot discharge water.

Water Flow Switch

A water flow switch is factory installed. The flow switch is wired in series with the 24 VAC safety control circuit at the

FIG. 33 Control Panel Component Location Drawing

units terminal strip. This wiring connection installs the flow switch in the 24 VAC safety circuit to prove water flow before main burner ignition. The factory supplied flow switch is installed in the outlet side of the front header. The 399,999 - 750,000 units require a minimum flow of 15 - 18 GPM whereas the 990,000 - 2,070,000 units require a minimum flow of 26 GPM to make the flow switch and start burner operation. Ensure that the pump installed on the unit will supply adequate flow to make the flow switch contacts and operate the unit. A water flow switch meets most code requirements for a low-water cut off device on appliances requiring forced circulation for operation.

Low Water Cutoff

(If Equipped)

If installing this unit above radiation level, you must install a low water cut-off device at the time of appliance installation. Electronic or float type low water cutoff controls are available as a factory supplied option on all units. Inspect the low water cutoff every six months, including flushing of float types. The low water cutoff control is located on the control panel directly behind the control panel cover.

The reset and test buttons (if equipped) are located on the control panel cover.

CONNECTING TO ELECTRICAL SUPPLY

This unit is wired for 120 VAC service. The unit, when installed, must be electrically grounded in accordance with the requirements of the authority having jurisdiction or in the absence of such requirements, with the latest edition of the National Electrical Code ANSI/NFPA No. 70. When the unit is installed in Canada, it must conform to the CAE C22.1, Canadian Electrical Code, Part 1 and/or local Electrical Codes.

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