John Wood Power Direct Vent (Non-ENERGY STAR qualified models) - Manual (Page 26)

V) OPERATION
Water Heater Operation
Figure 19 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 con-
trol does not detect ignition it will enter lockout mode. The
Robertshaw control will display a System Status Code (see
Table 2), the White-Rodgers control will flash the corre-
sponding error code.
Burner Flames
Inspect the burner flames through the viewport and com-
pare them to the drawings in Figure 20. A properly operat-
ing burner should produce a soft blue flame. Blue tips with
yellow inner cones are satisfactory. The tips of the flame
may have a slight yellow tint. The flame should not be all
yellow or have a sharp blue-orange colour. Contaminated
air may cause an orange coloured flame. Contact a qualified
service technician if the flame is not satisfactory.
Stacking
Stacking occurs when a series of short draws of hot water
(11 litres (3 US gallons) 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 tempering device is recommended in the hot
water supply line to reduce the risk of scald injury.
Emergency Shut Down
Important: Should overheating occur or the gas supply fails
to shut off, turn off the water heater’s manual gas control
valve and call a qualified service technician.
The thermostat is adjusted to its lowest temperature when it
is shipped from the factory. Water temperature can be reg-
ulated by moving the temperature dial to the preferred set-
ting. The preferred starting point is 49°C (120°F). Align the
index bar on the thermostat with the desired water temper-
ature as shown in Figure 16. There is a hot water scald
potential if the thermostat is set too high.
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 set-
ting. This will maintain the water at low temperatures with
minimum energy losses and prevent the tank from freezing
during cold weather.
Operational Conditions
Condensation
Moisture from the products of combustion condenses on the
tank surface and the outside jacket of the water heater and
forms drops of water, which may fall onto the burner or other
hot surfaces. This will produce a “sizzling” or “frying” noise.
This condensation is normal and should not be confused
with a leaking tank. Condensation may increase or
decrease at different times of the year.
– 26 –
CORRECT FLAME
SOFT BLUE
INCORRECT
FLAME LAZY
YELLOW
Figure 20 Flame Characteristics
TIPS MAY HAVE
A YELLOW TINT
YELLOW INNER
CONES ARE
SATISFACTORY
WARNING
Keep the area around the heater clear and
unobstructed.
CONTROL CHECKS TO
ENSURE 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
VALVE IS OPENED
MAIN BURNER ON AND
THE FLAME IS
SENSED BY CONTROL
MAIN BURNER
CONTINUES TILL THE
WATER IN THE TANK
REACHES
THERMOSTAT
SETTING
MAIN BURNER SHUTS
OFF. BLOWER
CONTINUES FOR A
POST PURGE TIME
CALL FOR
HEAT
Figure 19 Sequence Of Operation