Lochinvar 90, 500 Minimum Pump Performance, Remote Sensor Installation, Heat Exchanger

Installation & Service Manual

7Domestic water heaters (continued)

Minimum Pump Performance

Based on heating potable water with a hardness of 8 to 25 grains per gallon and total dissolved solids not exceeding 350 ppm. See “Water Chemistry”, page 47.

BTU/hr INPUT	GPM	Ft. Hd.
90,000 - 500,000	30	8

Remote Sensor Installation

Water heaters are provided with an extra temperature sensor that MUST BE field installed. The sensor is shipped loose in the I & O packet. This remote mounted sensor will be the primary temperature sensor which will inform the appliance’s built-in thermostat control. For domestic water heating, the sensor MUST BE installed into a bulbwell on the storage tank. This is required to maintain the desired temperature in the tank and reduce cycling of the heater.

The sensor must also be connected to two blue wires provided in the upper left-hand corner of the control panel. It will be necessary to add additional wire to reach from the appliance to the remote water source. Use twisted pair wire, minimum 18 gauge or larger. See Table 5A, page 33 regarding distance versus wire gauge. INSTRUCTIONS

EXTERNAL SENSOR FOR TANK, SYSTEM OR PUMP DELAY

REMOTE SENSOR CONNECTOR IS	NOTE: COLOR OF WIRES AND
LOCATED ON SIDE OF UNIT.	LEAD STYLES MAY VARY
	WITH SENSOR PROVIDED.
	CONNECTIONS ARE POLARITY
	INSENSITIVE.
SIDE PANEL

Figure 7-4_External Sensor for Tank, System or Pump Delay

Heat Exchanger

This is a highly sophisticated heat exchanger, designed to carry water in such a way that it generates a scouring action which keeps all interior surfaces free from build-up of impurities. The straight-line, two pass design of the tubes sends water into the headers at a properly rated velocity. The configuration of the headers, in turn, creates a high degree of turbulence which is sufficient to keep all contaminants in suspension. This “scouring action” provides greater cost savings for owners. Tubes are always able to transfer heat at peak efficiency. Every surface within this water containing section is of a nonferrous material, providing clear, clean, rust-free hot water. Straight copper tubes-finned on the outside for maximum heat transfer glass lined cast iron one piece cored headers make up an entirely rustproof unit. On all models, header inspection plugs can be removed for field inspection and cleaning of copper tubes. The entire heat exchanger may be easily removed from the unit.

Thermostat Settings

1.The thermostat is adjusted to a low test setting when shipped from the factory.

2.Set the thermostat to a maximum water temperature of 125°F which will satisfy hot water demands and prevent risk of scald injury.

Households with small children or invalids may require 120°F or lower temperature setting to reduce risk of scald injury. Some states may require a lower temperature setting. Check with your gas supplier for local requirements governing the temperature setting. Remember, no water heating system will provide exact temperature at all times. Allow a few days of operation at this setting to determine the correct temperature setting consistent with your needs.

NOTICE	(1) This water heater, when set at the
	lower temperature setting, is not capable
	of producing hot water of sufficient
	temperature for sanitizing purposes. (2)
	Higher stored water temperature
	increases the ability of the water heater to
	supply desired quantities of hot water,
	however remember:
	Hotter water increases the risk of scald
￿ CAUTION
	injury.

Incorrect piping of the cold water supply to the system may result in excessive low temperature operation causing condensate formation on the heat exchanger and operational problems. The cold water supply piping must be installed in the discharge piping from the heater to the storage tank. This allows the cold water to be tempered in the storage tank before entering the heater. See typical installation drawings provided in this manual. Higher water temperatures reduce condensate formation.

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