1. What should you do if the heater is not powering up?
Answer: First, verify the source power issue. Check if the voltage selector plug is correct. Inspect wires and connections for any damage. Test the FC1 and FC2 fuses for continuity. If the incoming power is correct and the fuses are not blown, proceed to test the transformer output for 22-28VAC. If any issues are found, replace the necessary components such as the fuse board or transformer.
2. How do you troubleshoot an open FC1 and/or FC2 fuse?
Answer: Ensure the correct voltage selector plug is installed. Inspect the transformer wiring for damage. Measure the transformer resistance between specified wires. If the resistance is out of range, replace the transformer. If the problem persists, contact technical support.
3. What steps should be taken if the FC3 and/or F1 fuse is open?
Answer: Check the remote connection and high limits for damage. Inspect the low voltage wiring and water pressure switch wiring. If any wiring is damaged, replace the wire harness or the specific component. Test the gas valve wires for continuity against the ground. If continuity is present, replace the gas valve.
4. How do you address an open FC4 fuse?
Answer: Inspect the ignitor and blower wiring for damage. Measure the resistance of the ignitor and blower. If the resistance is out of range, replace the faulty component. For models manufactured before September 2010, measure the blower resistance across specified wires.
5. What does the 'BD' code indicate and how is it resolved?
Answer: The 'BD' code indicates a bad board or secondary high voltage fault. Power down the heater and check the FC4 fuse for continuity. If the fuse is blown, replace it. Verify the voltage across specified pins on the fuse board and ICB. Replace the necessary components based on the voltage readings.
6. How do you clear an 'EE' or 'CE' code?
Answer: The 'EE' code indicates a defective ICB board, which should be replaced. The 'CE' code may clear with a power reset. If the error persists, inspect the display interface ribbon cable and ensure it is securely attached. Replace the display interface assembly or ICB if necessary.
7. What should be done if the 'IO' or 'SB' code appears?
Answer: The 'IO' code indicates an ignitor circuit open. Inspect the ignitor wiring and verify the ignitor ohm resistance. If the resistance is out of range, replace the ignitor. The 'SB' code indicates a stuck button, which may require replacing the display/bezel/keypad.
8. How do you troubleshoot an 'SF' or 'HS' code?
Answer: The 'SF' code indicates a sensor failure. Check the thermistor resistance between specified wires. If the readings differ by more than 1°, replace the thermistor. The 'HS' code indicates high water temperature. Ensure the water inlet and outlet are plumbed correctly.
9. What actions are necessary for a 'PF' code?
Answer: Verify that the incoming power is within 10% of the required voltage. Inspect the ground and neutral connections for cleanliness and security. If the connections are secure and the voltage is correct, replace the ICB.
10. How do you resolve an 'HF' code?
Answer: The 'HF' code indicates heat or flame sensed when the gas valve should be off. Power cycle the heater and test for 24VAC off the gas valve. If 24VAC is present and manifold pressure is not, replace the gas valve. Otherwise, replace the ICB.
11. What should be checked if the 'LO' code is displayed?
Answer: Verify adequate water flow and inspect the water pressure switch wiring. Check the continuity of the water pressure switch. If the switch is open, replace it. Inspect and test the high limits and vent pressure switch.
12. How do you address an 'IF' code?
Answer: Ensure the main gas supply is on and the gas valve inside the heater is in the 'ON' position. Verify the flame sensor and gas valve connections. Check the inlet and manifold gas pressures. Replace the gas valve or ICB if necessary.
13. What steps are involved in troubleshooting an 'AC' code?
Answer: The 'AC' code indicates the blower vacuum switch is closed when expected to be open. Test for continuity on the blower vacuum switch. If continuity exists, replace the switch. If the blower continues to run with the heater off, replace the ICB.
14. How do you resolve an 'AO' code?
Answer: The 'AO' code indicates the blower vacuum switch is open. Check the blower vacuum switch wires and vacuum tubing for damage. Verify the voltage selector plug and measure the blower resistance. Replace the necessary components based on the findings.
15. What is the procedure for programming the heater bypass operation?
Answer: Press the 'MENU ICON' button to place the heater in 'STANDBY'. Press and hold the minus button and 'MENU ICON' button for 3 seconds. 'bo' should appear on the display when the heater has successfully entered bypass mode.
16. How do you program the temperature lock-out?
Answer: Press the 'MENU ICON' button to place the heater in 'STANDBY' mode. Press and hold the minus and plus buttons for 3 seconds. Adjust the temperature using the minus or plus button. Finalize by pressing the 'MENU ICON' button until the heater returns to 'STANDBY'.
17. What are the flow requirements for the heat exchanger?
Answer: The minimum flow requirement varies by model, with a maximum water flow of 125 GPM. Flow less than the minimum can cause issues such as dry firing or boiling water, while exceeding the maximum can damage the heat exchanger.
18. How do you inspect the heat exchanger?
Answer: Remove the black metal trim plate and water connection side upper end cap. Disconnect unions from plumbing and remove hex head bolts. Remove the water manifold to expose the heat exchanger tubes. Inspect for damage from aggressive water chemistry.
19. What are potential failure causes for the heat exchanger?
Answer: Potential failure causes include low pH, high sanitizer levels, annealed fins due to low water flow, freeze damage, high pH, alkalinity or calcium hardness, and sooted conditions from improper fuel and air mixture.
20. How do you test and adjust gas pressure?
Answer: Measure the inlet static pressure and load pressure. Adjust the manifold pressure at the gas valve if necessary. Ensure the inlet gas pressure meets the requirements set forth by the data plate on the heater.
21. What should be done if the heater fails to light?
Answer: If the heater fails to light, the gas valve de-energizes for a 30-second blower post purge. The sequence retries three times until lockout (IF code) and waits 60 minutes before retrying. Ensure all connections and pressures are correct.
22. How do you verify electrical and gas connections?
Answer: Check connections located on both the left and right side of the heater cabinet. Ensure low voltage, high voltage, and gas supply connections are secure. Verify the control hookup is located outside the control box.
23. What are the safety precautions for handling the heater?
Answer: Only qualified technicians should attempt repairs. Replace damaged wiring immediately and ensure the heater is properly grounded and bonded to reduce the risk of electrocution and electric shock hazards.
24. How do you handle a 'Polarity Failure' (PF) code?
Answer: Ensure the voltage is within 10% of the required voltage. Verify both neutral and ground connections are clean and secured. If the connections are correct and the error persists, replace the ICB.
25. What is the sequence of operation for the heater?
Answer: The control checks for an open blower vacuum switch, starts a pre-purge cycle, and checks for a closed blower vacuum switch. At proper ignitor temperature, a 4-second trial begins. The gas valve opens, and the flame is monitored. The blower operates for a 30-second post purge.
26. How do you test the continuity of the water pressure switch?
Answer: Remove wires from the water pressure switch and measure continuity across the terminals while the pump is running. If open, replace the pressure switch.
27. What should be done if the exhaust gas limit switch does not have continuity?
Answer: Test continuity across the exhaust gas limit switch. If open, replace the switch. If the switch does not exist and the problem persists, contact support.
28. How do you verify the correct flame sensor is installed?
Answer: Verify that the installed flame sensor is 5 inches. If a 3-inch sensor is installed or if the sensor is damaged, replace it with the 5-inch version
29. What are the steps for inspecting orifices and burner tubes?
Answer: Inspect gas orifices and burners for blockage. Clean as required. If damaged, replace the components. If not damaged and the problem persists, contact technical support.
30. How do you ensure the blower vacuum switch is functioning correctly?
Answer: Isolate the blower vacuum switch and measure continuity between switch terminals. If continuity exists, replace the switch. If the blower continues to run with the heater off, replace the ICB.
