Operating The Temperature Control System; Gas Control Valve/Thermostat - John Wood POWER VENTED GAS FIRED WATER HEATER Installation And Operating Instructions Manual

Operating The Temperature Control
System
It is recommended that lower water temperatures be used
to avoid the risk of scalding. It is further recommended, in
all cases, that the water temperature be set for the lowest
temperature which satisfi es your hot-water needs. This will
also provide the most energy effi cient operation of the water
heater.
Short repeated heating cycles caused by small hot-water uses
can cause a temperature increase of the hot water by 11C°
(20F°) higher than the heater's temperature settings. If you
experience this type of use you should consider using lower
temperature settings to reduce scald hazards.
DANGER
HOT
HOT
BURN
HOT WATER CAN SCALD:
Water heaters are intended to produce hot water. Water
heated to a temperature which will satisfy space heating,
clothes washing, dish washing, and other sanitizing needs
can scald and permanently injure you upon contact. Some
people are more likely to be permanently injured by hot water
than others. These include the elderly, children, the infi rm,
or physically/mentally handicapped. National plumbing code
requirements limit the temperatures of certain fi xtures in the
home. Local codes may have additional requirements. If
anyone using hot water from this heater fi ts into one of these
groups or if there is a local code or state law requiring certain
temperature water at the hot-water tap, then you must take
special precautions. In addition to using the lowest possible
temperature setting that satisfi es your hot-water needs, a
means such as a mixing valve, should be used at the hot-
water taps used by these people or at the water heater. Mixing
valves are available at plumbing supply or hardware stores
(see Figure 11 & 12). Follow manufacturer's instructions for
installation of the valves. Before changing the factory setting
on the thermostat, in this manual, see Table 3.
The water heater should be located in an area where the
general public does not have access. If a suitable area is not
available, a cover should be installed over the thermostat to
prevent tampering.
Water temperature over
125°F (52°C) can cause
severe burns instantly
resulting in severe injury or
death.
Children, the elderly and the
disabled and are at highest
risk of scald injury.
Feel water before bathing or
showering.
Temperature limiting devices
such as mixing valves must
be installed when required
by codes and to ensure safe
temperatures at fixtures.
Read instruction manual for
safe temperature setting.
The water temperature setting was factory set at the lowest
temperature.
This water heater is equipped with an adjustable thermostat
to control water temperature. Hot water temperatures required
for automatic dishwasher and laundry use can cause scald
burns resulting in serious personal injury and/or death. The
temperature at which injury occurs varies with the person's
age and time of the exposure. The slower response time of
children, aged or disabled persons increases the hazards to
them. Never allow small children to use a hot-water tap, or
to draw their own bath water. Never leave a child or disabled
person unattended in a bathtub or shower.
Setting the water heater temperature at 49°C (120°F) will
reduce the risk of scalds.
Should overheating occur or the gas supply fails to shut
off, turn off the manual gas control valve/thermostat to the
appliance.

Gas Control Valve/Thermostat

ON/OFF TEMPERATURE
SWITCH
SETTING DIAL
Figure 35
Approximate
Temperature
Temperature
Dial Setting
VERY HOT
C
B
A
HOT
LOW
VAC
Table 3
Note: The temperatures indicated are approximate. The actual
temperature of the heated water may vary.
The Vacation Setting (VAC) sets the controller at approximately
21°C (70°F). 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.
– 25 –
54°C 60°C 65°C
(130°F) (140°F) (150°F)
49°C 43°C
(120°F) (110°F)
Time to induce a 2nd
and 3rd Degree burn to
°C (°F) adult skin
68 (155) Less than 1 second
65 (150) Less than 3 seconds
60 (140) About 5 seconds
54 (130) About 30 seconds
49 (120) More than 5 minutes
43 (110) Normal shower temp
21 (70) N/A
68°C
(155°F)
21°C
(70°F)