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 sufficient room to service the water heater. See Clearances on page 54.

2.Ensure the area is free of corrosive elements and flammable materials. See the instructions on page54.

Venting

3.Ensure the intake air and/or vent (exhaust) piping is the correct size for the installed length. See Venting Requirements on page 54.

4.Ensure the maximum equivalent feet of pipe has not been exceeded for the intake air and/or vent pipe. See Table 7 on page 54.

5.Ensure the maximum number of elbows has not been exceeded in the intake air and/or vent pipe. See Venting Requirements on page 54.

6.Ensure the balance plate and intake air screen are removed from the intake air connection on the water heater when installing the water heater in a Direct Vent configuration. See Figure 17 on page 54.

7.Ensure all exterior clearances for the intake air, vent and concentric terminations are maintained. See Vertical Termination Installation on page 54, Sidewall Termination Installation on page 54 and Concentric Termination Installation on page 54. These clearances and those cited by local and national codes must be maintained.

Gas Supply And Piping

8.Ensure a supply gas regulator has been installed for each water heater. See the requirements for a Supply Gas Regulator on page 54 and Supply Gas Regulator Installation on page 54.

9.Ensure the supply gas line to each water heater meets the minimum supply gas line size requirements. See the requirements for the Supply Gas Line on page 54 and the installation instructions on page 54 and 54.

Condensate Drain

10.Ensure the condensate drain is properly connected to the exhaust elbow on the water heater with a water trap to prevent vent gases from escaping into the installed space and draining freely to a suitable floor drain. See Figure 9 on page 54 and Condensate Drain Installation on page 54.

Electrical Connections

11.Ensure the power supply connections to the water heater are polarity correct. See the requirements for the Power Supply on page 54 and Electrical Wiring on page 54.

12.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.

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 54 for the location of various water heater components described below. See the Sequence Of Operation Flow Chart on page 54 also.

1.When the control system is first 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 confirming the low gas pressure, blocked exhaust, blocked intake and ECO (energy cut out) switch contacts are closed. The Blower Prover Switch contacts are confirmed open.

4.If all diagnostic checks are successfully passed, the control system energizes the Combustion Blower for pre-purge.

5.The control system must confirm the Blower Prover Switch contacts close after the Combustion Blower is energized.

6.If the Blower Prover Switch contacts are confirmed closed the control system energizes the Hot Surface Igniter for the igniter warm-up period.

7.The control system monitors the igniter current and must sense a minimum of 2.0 AC amps for SUF 130 300 & 400 models and 3.1 AC amps for SUF 130 500 models during the igniter warm up period (12-17 seconds).

8.If igniter amperage is confirmed at or above the required minimum the control system energizes the 24 VAC Gas Valve allowing gas to flow to the Main Burner.

9.The control system de-energizes the Hot Surface Igniter.

10.The control system monitors the flame sensor to confirm a flame is present at the Main Burner. If a flame is not verified during the ignition trial period the control system will try for ignition up to two more times. If flame can not be verified after three trials for ignition, the control system will lock out and display the “Ignition Failure” Fault message.

11.If a flame is verified, 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 VAC Gas Valve and enter the post-purge cycle (approximately 30 seconds).

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.