Lochinvar Power-Fin 502 Installation & Operation Manual page 71

9
Domestic water heaters
The following chart (Table 9E) details the relationship of water
temperature and time with regard to scald injury and may be
used as a guide in determining the safest water temperature for
your applications.
TABLE 9E
APPROXIMATE TIME / TEMPERATURE
RELATIONSHIPS IN SCALDS
120°F
125°F
130°F
135°F
140°F
145°F
150°F
155°F
Setting the temperature selector to higher
CAUTION
settings provides hotter water, which
increases the risk of scald injury.
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 9-1 thru 9-4). Higher
water temperatures reduce the volume of condensate formed.
Should overheating occur or the gas supply
WARNING
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.
Adjustable high water temperature limit
control
Figure 9-6_Adjustable High Water Temperature Limit Control
More than 5 minutes
1 1/2 to 2 minutes
About 30 seconds
About 10 seconds
Less than 5 seconds
Less than 3 seconds
About 1 1/2 seconds
About 1 second
Installation & Operation Manual
(continued)
A high limit control is located on the inside of the left front
panel, as shown in FIG. 9-6. 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.
The high limit control will not reset until the
NOTICE
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. Do not
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.
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