Certain Rheem water gas water heater models feature electronic controls with a flammable vapor sensor installed on the bottom portion of the water heater unit. This sensor is designed to shut off your water heater system to prevent fires in case flammable vapors are present within the area. If your flammable vapor sensor caused your water heater to shut down, check the area immediately for leaking gas or other flammable products. Common household chemicals such as bleach can also trip the safety system as well as unsuccessful burner ignition attempts.
White Rodgers Intelli-Vent PowerVent Control Equipped Models
Turn the water heater's blower switch off and disconnect the power cord for the water heater (refer to your particular model's operation guide for the exact location of the blower switch). Disconnect the Molex connector attached to the bottom of the control pad (the left most connector with five pins).
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Turn on your multi-meter and set it to read resistance or "ohms". Connect one of the multi-meter's probes to the number two pin and the other probe to the number three pin of the Molex connector (middle black wires). If the reading on your multi-meter reads below 9k or above 45k ohms, the flammable vapor sensor is faulty and in need of replacement; you cannot reset the system until this issue is resolved.
Reconnect the Molex connector to the bottom of the control pad, reconnect the water heater's power if and turn the blower switch to the "ON" position. Press both the left and right buttons on the control pad at the same time. Wait for the green light on the control pad to blink and press the following buttons in sequence: Left, Right, Left, Left, Right, Left, Right, Right (you will need to perform these actions within 30 seconds of reconnecting the power cord to the water heater in order to be successful).
Honeywell Gas Control Equipped Models
Check around your hot water heater for flammable products and for a natural gas leak. Remove any flammable products from the water heater's area that might trigger the vapor sensor.
Call your local fire department and/or gas company immediately if you smell the presence of natural gas. Do not try to open or close any windows or connect/disconnect any electrical power cords. Evacuate the home as soon as possible to avoid injury or possible death.
Turn the water heater's gas valve switch to the "OFF" position, wait for a few seconds and then flip the switch to the "ON" position to reset the system. The water heater's gas valve is located near the bottom of the unit and connects to your home's natural gas line. If your water heater does not begin working or another "lock out" condition occurs, have a competent hot water heating specialist diagnose the system and make repairs.