Lochinvar 402 - 2072 Optional relief valve, Thermal expansion, Cathodic protection, Notice

8 Domestic water heaters

Figure 8-5_Danger Warning

Location of Cold Water Supply Piping Connections

Incorrect piping of the cold water supply to the system may result in excessive low temperature operation causing condensate formation on the primary 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 for correct piping (FIG.’s 8-1 thru 8-4). Higher water temperatures reduce the volume of condensate formed.

￿ CAUTION	Setting the temperature selector to higher
	settings provides hotter water, which
	increases the risk of scald injury.

￿WARNING Should overheating occur or the gas supply fail to shut off, do not turn off or disconnect

the electrical supply to the pump. Instead, shut off the gas supply at a location external to the appliance.

Optional adjustable auxiliary high water temperature limit control

ADJUSTABLE AUXILIARY HIGH WATER TEMPERATURE LIMIT CONTROL (OPTION)

Installation & Operation Manual

A high limit control is located on the inside of the left front panel, as shown in FIG. 8-6. The setting of this control knob limits maximum discharge water temperature. The water heater temperature limit control is adjustable up to a maximum setting of 210°F (99°C). This water heater also includes a fixed high water temperature limit control set to 200° (93.3°C). The RESET key on the display must be pushed whenever water temperature has exceeded the set point of the limit. The temperature of the water in the heat exchanger must drop a minimum of 15°F (8.3°C) below the setting of the high limit control before the reset function can be activated. A high limit message will be shown in the Operator Interface when water temperature exceeds the high water temperature limit control set point.

NOTICE	The high limit control will not reset until the
	water temperature has dropped below the set
	point of the high limit.

Optional relief valve

This water heater is normally supplied with a temperature and pressure relief valve sized in accordance with applicable codes. Units may be supplied with an optional pressure only relief valve. When a water heater is equipped with this optional relief valve and is piped to a separate storage vessel, the storage vessel must have a properly installed temperature and pressure relief valve which complies with local codes.

Thermal expansion

A relief valve that discharges periodically may be due to thermal expansion in a closed system. A water heater installed in a closed system, such as one with a backflow preventer or check valve installed in the cold water supply, shall be provided with means to control expansion. Contact the water supplier or local plumbing inspector on how to correct this situation. Never plug or cap the relief valve discharge.

Cathodic protection

Hydrogen gas can be produced in a hot water system that has not been used for a long period of time (generally two weeks or more). Hydrogen gas is extremely flammable. To prevent the possibility of injury under these conditions, we recommend the hot water faucet be open for several minutes at the kitchen sink before you use any electrical appliance which is connected to the hot water system. If hydrogen is present, there will be an unusual sound such as air escaping through the pipe as the hot water begins to flow. There should be no smoking or open flames near the faucet at the time it is open.

Figure 8-6_Adjustable Auxiliary High Water Temperature Limit Control

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