Installation Manual

7
BASIC OPERATION
The water heaters covered in this manual have a helical coil
shaped heat exchanger that is submerged in the storage tank.
The water heater’s Main Burner is a radial design burner, it
is mounted on the top and res downward through the heat
exchanger. This is a forced draft burner; hot burning gases are
forced through the heat exchanger under pressure and exit
through the exhaust/vent connection located at the bottom of the
water heater. See Figure 1 and Figure 2.
BLOWER
BURNER
ASSEMBL
Y
MAIN
BURNER
(radial design)
HEAT
EXCHANGER
INTAKE AIR
(combustion air)
CONNECTION
4 INCH PVC
HELICAL
COIL
VENT (exhaust)
OUTLET
Figure 1
FEATURES AND COMPONENTS
MODULATION
The water heaters covered by this manual are capable of modulating
their ring rate. The CCB monitors the water temperature in the
tank and regulates the ring rate to achieve the target temperature
setpoint. The ring rate is dictated by the hot water draw, proximity
to the tank temperature setpoint, and various other temperature
limitations. Periodically, when the heater is in modulation mode, the
CCB will increase the blower speed for a short period of time to clear
out any condensation that has accumulated in the heat exchanger
then decreases the blower speed back to the modulating ring rate
required to maintain the desired tank temperature setpoint. This
ramping up and down of the blower speed is considered normal
operation of the water heater.
BLOWER/BURNER ASSEMBLY DETAIL
SPARK
IGNITER
COMBUSTION
BLOWER
FLAME SENSOR
MAIN BURNER
(radial design)
BLOWER
FLANGE
INTAKE AIR
(combustion air)
CONNECTION
4 INCH PVC
Figure 2
Spark Electrode
The control system energizes the spark ignition control with
120 VAC during the ignition period. The spark ignition control
then sends an electrical current to the spark igniter which in turn
ignites the main burner air/gas mixture.
See the Sequence of Operation on page 54.
Flame Sensor
The control system also monitors the ame sensor to conrm
a ame is present at the Main Burner. If a ame is not veried
during the ignition trial period (3-5 seconds) the control system
will immediately de-energize the 24 VAC Gas Valve. See the
Sequence of Operation Flow Chart on page 55.