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100221773_2000189439_Rev. 01
Some people are more likely to be permanently injured
by hot water than others. These include the elderly,
children, the infirm and the physically/mentally disabled.
Table 1 (published by U.S. Government Memorandum,
1978) shows the approximate time-to-burn relationship
for normal adult skin. If anyone using hot water provided
by the water heater being installed fits into one of these
groups or if there is a local code or state law requiring a
certain water temperature at the point of use, then special
precautions must be taken.
Water
Temperature
°F
Time for 1st
Degree Burns
(Less Severe Burns)
Time for Permanent
Burns 2nd & 3rd
Degree (Most
Severe Burns)
110
(normal shower temp.)
116
(pain threshold)
116
35 minutes
45 minutes
122
1 minute
5 minutes
131
5 seconds
25 seconds
140
2 seconds
5 seconds
149
1 second
2 seconds
154
instantaneous
1 seconds
(U.S. Government Memorandum, C.P.S.C., Peter L. Armstrong,
Sept. 15,1978)
Table 1.
In addition to using lowest possible temperature setting
that satisfies demand of application, a mixing valve should
be installed at water heater (see Figure 8 & Figure 9) or at
hot-water taps to further reduce system water temperature.
Mixing valves are available at plumbing supply stores.
Consult a Qualified Installer or Service Agency. Follow
mixing valve manufacturer’s instructions for installation
of the valves. Before changing the factory setting on the
thermostat, read the “Operating The Temperature Control
System” section in this manual.
WATER HEATER OPERATION
Figure 11 shows the water heater’s sequence of operation
when a call for heat is initiated. The ignition control module
will attempt to light the burner three times. If the ignition
control does not detect ignition it will enter lockout mode
and flash the corresponding error code.
HEATER CONTROL
CHECKS TO ENSURE
BLOWER PRESSURE
SWITCH IS OPEN
BLOWER IS ENERGIZED
CONTROL CHECKS TO
ENSURE PRESSURE
SWITCH CLOSES
INDICATING BLOWER
IS OPERATING AND
THERE ARE NO VENTING
BLOCKAGES (INLET OR
OUTLET)
IGNITER IS ENERGIZED
AND MAIN GAS VALVE IS
OPENED
MAIN BURNER COMES
ON AND THE FLAME IS
SENSED BY CONTROL
MAIN BURNER
CONTINUES UNTIL THE
WATER IN THE TANK
REACHES THERMOSTAT
SETTING
MAIN BURNER
SHUTS OFF. BLOWER
CONTINUES FOR A POST
PURGE TIME
HEATER
THERMOSTAT
CALLS FOR HEAT
HEATER REMAINS
ON STANDBY UNTIL
NEXT CALL FOR
HEAT
Figure 11.