Rheem Water Heater Vapor Sensor Keeps Tripping – Fixed!

Do you rush to get another sensor when the old one malfunctions? Sometimes, the vapor sensor is not the culprit. You should know that these gadgets are designed to last for over a decade. 

So then, why does your Rheem water heater vapor sensor keep tripping? 

Dust and chemical vapors from household cleaning agents can trigger vapor sensors—safety gadgets that shut down the unit when it detects flammable vapors. Sometimes, leaking sewage gas can also set off these sensors erroneously.

This article will explore why your Rheem water heater flammable vapor sensor keeps tripping. What’s more? You’ll learn how to fix it, too! 

How Do Vapor Sensors Work? 

Know thy enemy, which in this case is your flammable vapor sensor.

A flammable vapor sensor is a safety gadget that shuts down the gas valve when there’s a significant concentration of flammable vapors that can ignite and cause fire outbreaks. It’s the job of these gadgets to detect them before a fire starts. 

In Rheem hot water heaters, the vapor sensor is located just beneath the jacket door at the bottom of the unit. It relays information to the gas valve. If there’s a problem with the sensor, the gas valve will beep seven times after a three-second pause. 

vapor sensor

Reasons Why the Vapor Sensor Keeps Tripping

There are quite a lot of reasons why your vapor sensors can keep tripping. 

Surprisingly, a little drop of cleaning agents can easily set it off. It’s why plumbers advise you not to place a water heater unit in the laundry room or any place close to gas pipes. 

Other reasons include:

Hydrocarbon Solvents 

Hydrocarbons are volatile and can easily ignite in the air. Sadly, most cleaning products contain these chemicals. For example, mineral spirits are the most diverse cleaning agent in homes. 

Water vapor sensors are designed to trip off within a minute of spilling hydrocarbon solvents. So always store your oil-based paints or finish in places far away from the unit. 

Dust and Debris 

Dust accumulates in the arrestor screen and prevents the free flow of air into the entire unit. Furthermore, the trapped air increases the water heater’s internal temperature, also triggering the sensor. 

High Temperature 

Vapor sensors can only work within a select temperature range (160°C to 200°C). Your sensor trips off when the temperature inside the combustion chamber is higher than the standard thermal ratings.

What’s more, the sensor connects to the thermal cutoff switch. This switch regulates the internal temperature of water heater units.

How to Vapor Sensor from Tripping in Rheem Hot Water Heater Heaters

Before you buy a (possibly unnecessary) replacement sensor, start with these troubleshooting options:

Reset Water Heater Vapor Sensor

As a DIYer, resetting the sensor should be your first course of action in gas water heaters. Thankfully, this process is not so complex. 

To reset your sensor, identify the gas control valve in your gas water heater. Most Rheem hot water heaters come with White Rodgers gas valves.

In this section, we’ll detail for you how to reset the sensor in different gas valves. 

How to Reset Vapor Sensor in White Rodgers Gas Valve

  1. Switch off or unplug the water heater from the main power supply. 
  2. Wait ten seconds, and then plug it back in.
  3. Once the flammable vapor error code appears, press both the left and right buttons at the same time.
  4. Hold it down for five seconds until the green light starts blinking. 
  5. Press the left and right buttons in the following order: Left, Right, Left, Left, Right, Left, Right, Right.
  6. If the reset is successful, all the LED lights will light up. 

How to Reset Vapor Sensor in Intelli-Vent Gas Valve

  1. Turn off the power supply to the heater. 
  2. Wait for at least ten seconds before switching on the unit. 
  3. Press both the left and right temperature buttons at the same time. Hold them down until the vacation LED light starts to blink.
  4. Press down on both buttons within the next ten seconds. Press them until the vacation LED light becomes stable. 
  5. The gas valve will reset and cancel out the error codes. 

How to Vapor Sensor in Honeywell Gas Valve

This method is quite different from other water heater gas valves. So take note of these steps:

  1. Unplug the unit from the main power switch. 
  2. Then, wait for ten seconds before plugging it back in. Once the unit is plugged in, you’ll have about 30 seconds to complete the next step. 
  3. Hold the switch on the gas valve. Turn it from the vacation setting to the very hot setting. 
  4. Repeat this motion five times to successfully reset the error code. 

Clean the Flame Arrestor Screen 

Clean and remove debris and dirt clogging up the flame arrestor or air intake screen. It’s preferable to install your unit in a dust-free environment. 

Place the unit on a platform. 

When you place the unit on the ground, it is easy for dust and sewage gas to clog up the vapor sensor. Gas vapors are also heavier than air molecules and do not rise above 18″ in a ventilated room. Try raising the unit at least 18 inches off the ground. 

When Should You Replace Your Vapor Sensor? 

What happens if the gas valve reset does not work? Try testing the resistance level before replacing your sensor. 

You can only replace the sensor if the resistance level is below 11k ohms or above 45k ohms. Use a millimeter to test the sensor and take note of the readings. 

Conclusion: Water Heater Vapor Sensor Keeps Tripping 

Now you know why the sensor keeps tripping. Use the above guide to solve the problem, and don’t forget to call a repairer if it gets too challenging.