John Wood Polaris Commercial High-Efficiency - Manual (Page 23)

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occurrence of igniter failure due to excessive condensate.
Important: A mixing valve (provided) must be installed in
the hot water outlet to reduce the risk of scald injury when
setting the thermostat in excess of 120°F (48.9°C).
Many home heating systems
used with this water heater are
designed for temperatures higher
than 130°F (54.4°C). Refer to
the manufacturer’s instruction
manuals supplied with this type
of equipment for recommended
temperature settings.
Important: Adjusting the
thermostat past the 120°F
(48.9°C) setting on the
temperature dial (see figure 22) will increase the risk of scald
injury. Hot water can produce first degree burns within:
(48.9°C)*
(54.4°C)*
(60°C)*
(48.9°C)*
(54.4°C)*
(60°C)*
* Temperatures shown are approximates
and may vary.
(48.9
° C)
(54.4
° C)
(60 ° C)
Figure 22:
Temperature Dial
Stacking
Stacking occurs when a series of short draws of hot water
(3 gallons [11.3 liters] or less) are taken from the water
heater tank. This causes increased cycling of the burner
and can result in increased water temperatures at the hot
water outlet. A mixing valve must be installed in the hot
water supply line to reduce the risk of scald injury.
Water Temperature Regulation
The thermostat is adjusted to its lowest temperature setting
when it is shipped from the factory. Water temperature
can be regulated by moving the temperature dial to the
preferred setting. The preferred starting point is 130°F
(54.4°C); however, in some instances, setting the water
heater higher than 130°F (54.4°C) can reduce the
Water temperature over 125°F (51.6°C) can cause
severe burns instantly or death from scalds.
Children, disabled and elderly are at highest risk
of being scalded.
See instruction manual before setting
temperature at water heater.
Feel water before bathing or showering.
Temperature limiting valves are available.
Water
Temperature
°F (°C)
Time for 1st
Degree Burn
(Less Severe Burns)
Time for Permanent Burns
2nd & 3rd Degree
(Most Severe Burns)
110 (43.3)
116 (46.7)
122 (50)
131 (55)
140 (60)
(U.S. Government Memorandum, C.P.S.C., Peter L. Armstrong, Sept. 15,1978)
(normal shower temp.)
(pain threshold)
35 minutes 45 minutes 116 (46.7)
1 minute 5 minutes
5 seconds 25 seconds
2 seconds 5 seconds
1 second 2 seconds 149 (65)
154 (67.8)
instantaneous 1 second
Table 4
Emergency Shut Down
Important: If overheating occurs or the gas supply fails to
shut off, close the manual gas supply valve. Turn off the
electrical supply to the unit and close the cold water supply
valve. Do not operate the water heater again until it has been
thoroughly checked by an authorized service technician.