John Wood Atmospheric Gas (Standard) - Manual (Page 22)

22
VAC
GAS CONTROL VALVE/THERMOSTAT
SETTINGS
GAS CONTROL/TEMPERATURE KNOB
STATUS
LIGHT
IGNITER
120°F (48.9°C)
MARK
FIGURE 17A.
Should overheating occur or the gas supply fail to shut off,
turn off the manual gas control valve to the appliance.
NOTE: During low demand periods when hot water is not
being used, a lower thermostat setting will reduce energy
losses and may satisfy your normal hot water needs. If hot
water use is expected to be more than normal, a higher
thermostat setting may be required to meet the increased
demand. When leaving your home for extended periods
(vacations, etc.) turn the temperature dial to its lowest
setting. This will maintain the water at low temperatures
with minimum energy losses and prevent the tank from
freezing during cold weather.
Operating the Temperature Control System
VAC
List of status codes are shown
at top of gas control valve/thermostat.
FIGURE 17B.
Water Temperature Adjustment
The water temperature setting can be adjusted from
55°F (12.7°C) to 155°F (68.3°C). Turn the Gas Control/
Temperature Knob to the desired setting/temperature.
NOTE:
•
Some models are certified for 180°F (82.2°C) outlet
temperatures. See the Data Plate on the front of the
water heater for the maximum outlet temperature.
• The temperatures indicated are approximates. The
actual temperature of the heated water may vary.
Operating Modes and Settings
•
Standard Mode - The controller adjusts the water
heater to maintain the temperature set by the user.
• Vacation Setting - The Vacation setting (VAC) sets the
controller at approximately 55°F (12.7°C). This setting
is recommended when the water heater is not in use
for a long period of time. This effectively turns the
controller temperature setting down to a temperature
that prevents the water in the water heater from
freezing while still conserving energy.
Status Light Code
Normal Flashes:
•
0 Flashes Indicates Control Off/Pilot Out.
• 1 Flash Indicates Normal Operation.
• A solid red light indicates that the gas control
valve/thermostat is shutting down.
Diagnostic Flashes:
If the water heater is not working, look for the following
diagnostic flashes after lighting the pilot. For more details, see
“Status Light and Diagnostic Code Troubleshooting Chart.”
2 Flashes Indicates Thermopile Voltage Low
4
Flashes Indicates Overheat Failure
5 Flashes Indicates Sensor Failure
7 Flashes Indicates Electronic Control Failure
8 Flashes See “Status Light and Diagnostic Code
Troubleshooting Chart.”
Operational Conditions
Condensation
Whenever the water heater is filled with cold water, some
condensate will form while the burner is on. A water
heater may appear to be leaking when in fact the water is
condensation. This usually happens when:
a. A new water heater is filled with cold water for the first time.
b. Burning gas produces water vapor in water heaters, par-
ticularly high efficiency models where flue temperatures
are lower.
c. Large amounts of hot water are used in a short time and
the refill water in the tank is very cold.
Moisture from the products of combustion condense on the
cooler tank surfaces and form drops of water which may fall
onto the burner or other hot surfaces to produce a “sizzling”
or “frying” noise.
Water Temperature
°F (°C)
Time for 1st Degree
Burn
(Less Severe Burns)
Time for
Permanent Burns
2nd & 3rd Degree
(Most Severe Burns)
110 (43)
116 (47)
116 (47)
122 (50)
131 (55)
140 (60)
149 (65)
154 (68)
(normal shower temp.)
(pain threshold)
35 minutes
1 minute
5 seconds
2 seconds
1 second
Instantaneous
45 minutes
5 minutes
25 seconds
5 seconds
2 seconds
1 second
(U.S. Government Memorandum, C.P.S.C., Peter L. Armstrong, Sept. 15,1978)