AO Smith ProMax Water Heater Troubleshooting

If you are having issues with your A O Smith ProMax Power Vent (C3FVIR) Water Heater, than this guide will hopefully help you resolve a variety of issues that could arise with this particular unit. In these tough times I can respect that not everyone can afford to hire a technician to repair every issue with appliances and other household staples. There are a multitude of problems that can go wrong with water heaters such as: water leaks, temperature/thermostat issues, odors, blower malfunctions among many other things. While most water heater issues can be solved by the average homeowner or landlord, if you feel that you can not safely make the repair please call in a certified technician.

PROBLEM: Not enough hot water.

SOLUTION: If there is not enough hot water first check to see that the switch is turned to the “ON” position and that the blower is plugged into a 115 VAC electrical outlet. If this does not work, the problem might be with the electrical outlet which will need to be repaired. If there are thermostat problems you might need to replace the thermostat. If the control harness is working improperly, try replacing it. If the high limit control circuit is open than replace the thermostat. Make sure the thermostat is not set too low, adjust the temperature setting accordingly. If the blower motor is defective than try replacing the blower assembly. Check and repair all possible leaks. Lastly, if your heater is undersized try reducing your hot water usage.

PROBLEM: Error in the Hot surface ignitor circuit.

SOLUTION: Check that all of the wiring is correct and secure. If the wiring is correct than you will most likely need to replace the hot surface ignitor.

PROBLEM: Water temperature sensor is either open or short circuited.

SOLUTION: First check that all the wiring is correct and secure. If the wiring is correct than you will probably need to replace the gas control valve.

PROBLEM: Pressure switch remained closed longer than 5 seconds after heat was requested.

SOLUTION: Check to see if the pressure switch wiring is correct and secure. If the wiring is correct than you should replace the pressure switch.

PROBLEM: Pressure switch remained open longer than 5 seconds after the combustion blower started up.

SOLUTION: Check pressure switch wiring to see if it is correct. Then check to see if the pressure switch tubing is connected properly. Check to see if air intake or exhaust is blocked.

PROBLEM: Water heater unit shuts down.

SOLUTION: Check to see if the wiring for the FV Sensor is correct. Then see if there are any open circuits to the FV Sensor. If the problem persists then replace the FV Sensor. If the Water heater locks you out after it shuts down consider cleaning and reinstalling the air intake screen on the blower assembly.

PROBLEM: Hot water or gas vent odors.

SOLUTION: Start by draining and flushing the heater and then refill it. Also make sure to chlorinate the water supply. If the problem continues it could be due to: lack of air supply, improperly installed vent piping, downdraft or poor combustion.

PROBLEM: Burner will not stay lit for more than 5 seconds.

SOLUTION: Try cleaning and reintalling the air intake screen as well as the lint screen on the blower assembly. Check to see if the flame arrestor is obstructed. Make sure the polarity on the electrical outlet that the heater is plugged into is not reversed. Also be sure that the ambient temperature in the room that the heater is in is not too high. The last thing you can try is replacing the gas valve as it may be working improperly.

PROBLEM: Water leaks.

SOLUTION: First make sure that the leak is not coming from any nearby appliances, then try tightening all threaded pipe connections. Next remove the cap on the rubber boot vent terminal of the blower assembly and install a drain tube to port as per required codes. If you have a leaking T&P valve install a thermal expansion tank and check relief valve to make sure it is operating correctly.

PROBLEM: Vent pipe is too hot.

SOLUTION: Make sure the air flow restrictor is working properly. Check to see if there is enough dilution air to mix with flue gases, also ensure that the dilution air is not too hot for mixing with flue gases.

PROBLEM: Yellow flame.

SOLUTION: Turn off the water heater and the gas and clean the burner head. Make sure there are no blockages in the air intake, exhaust ventings, and air openings in the bottom of the base pan.