Install Instructions

57
SEQUENCE OF OPERATION
Read the Sequence of Operation below before attempting to
correct any operational problems. Refer to the Features And
Components section beginning on page 7 for the location
of various water heater components described below. See the
Sequence Of Operation Flow Chart on page 58 also.
1. When the control system is rst powered, during boot
up, it will display water heater model information during
initialization. After a few moments the control system LCD
which is part of the UIM (user interface module) will display
the default screen known as the "Desktop" screen.
2. If the control system determines that the actual water
temperature inside the tank is below the programmed
Operating Set Point minus the Differential setting, a heating
cycle is activated.
3. The control system then performs selected diagnostic
system checks. This includes conrming the low gas
pressure, blocked exhaust, blocked intake and ECO (energy
cut out) switch contacts are closed. The Blower Prover
Switch contacts are conrmed open.
4. If all diagnostic checks are successfully passed, the control
system energizes the Combustion Blower for pre-purge.
5. The control system must conrm the Blower Prover Switch
contacts close after the Combustion Blower is energized.
6. If the Blower Prover Switch contacts are conrmed closed
the control system energizes the Spark Ignition Control.
7. The control system energizes the 24 Volt Gas Valve allowing
gas to ow to the Main Burner.
8. The control system 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 the control system will
try for ignition up to two more times. If ame can not be
veried after three trials for ignition, the control system will
lock out and display the “Ignition Failure” Fault message.
9. If a ame is veried, the control system will enter the heating
mode where it will continue heating the water until the
Operating Set Point is reached. At this point, the control
system will de-energize the 24 Volt Gas Valve and enter the
post-purge cycle (approximately 30 seconds).
10. The control system de-energizes the Spark Ignition Control.
11. The water heaters covered by this manual are capable of
modulating their ring rate. The ring rate is dictated by the
hot water draw and various other temperature limitations.
12. The Combustion Blower will run for the duration of the post-
purge cycle to purge the water heater of all combustion
gases. When the post-purge cycle is complete, the blower is
de-energized and will coast to a stop.
13. The control system now enters the standby mode while
continuing to monitor the internal storage tank water
temperature and the state of other system devices. If the
tank temperature drops below the Operating Set Point
minus the Differential setting, the control will automatically
return to Step 2 and repeat the operating cycle.
TROUBLESHOOTING
INSTALLATION CHECKLIST
The list below represents some of the most critical
installation requirements that, when overlooked, often result
in operational problems, down time and needless parts
replacement. This is not a complete list. Before performing
any troubleshooting procedures use the list below to check
for installation errors. Costs to correct installation errors are
not covered under the limited warranty. Ensure all installation
requirements and instructions in this manual have been
maintained and followed.
WATER HEATER LOCATION
1. Ensure proper clearances to combustibles are maintained
and there is sufcient room to service the water heater. See
Clearance To Combustible Materials on page 12.
2. Ensure the area is free of corrosive elements and ammable
materials. See the instructions on page16.
VENTING
1. Ensure the intake air and/or vent (exhaust) piping is
the correct size for the installed length. See Venting
Requirements on page 22.
2. Ensure the maximum equivalent feet of pipe has not been
exceeded for the intake air and/or vent pipe. See Table 6 on
page 23.
3. Ensure the maximum number of elbows has not been
exceeded in the intake air and/or vent pipe. See Venting
Requirements on page 22.
4. Ensure the intake air screen has been removed from the
intake air connection on the water heater when installing the
water heater in a Direct Vent conguration. See Figure 18
on page 25.
5. Ensure all exterior clearances for the intake air, vent,
concentric, and low prole terminations are maintained.
See Vertical Termination Installation on page 25,
Sidewall Termination Installation on page 27, Concentric
Termination Installation on page 30 and Low Prole
Termination Installation on page 34. These clearances and
those cited by local and national codes must be maintained.
GAS SUPPLY AND PIPING
1. Ensure a supply gas regulator has been installed for each
water heater. See the requirements for a Supply Gas
Regulator on page 13.
2. Ensure the supply gas line to each water heater meets
the minimum supply gas line size requirements. See the
requirements for the Gas Supply Systems on page 13
and the installation instructions on page 40 and 41.
CONDENSATE DRAIN
Ensure the condensate drain is properly connected to the
exhaust elbow on the water heater and draining freely to a
suitable oor drain. See Figure 8 on page 16 and Condensate
Drain Installation on page 39.
ELECTRICAL CONNECTIONS
1. Ensure the power supply connections to the water heater
are polarity correct. See the requirements for the Power
Supply on page 13 and Electrical Wiring on page 41.
2. Ensure the water heater is properly grounded. Flame
sensing requires an adequate earth ground. If the water
heater is not properly grounded it will cause Ignition Failure.