What resistence does Flammable Vapor Sensor need to have to be considered good?

I personally wouldn't replace a safety device (placed there by lawyers, lawsuits and the all knowing government) with anything other than OEM. While it's very likely that one manufacturers flammable vapor sensor may interchange on another brand of tank, I think it's highly unlikely that EVERY manufacturers sensor will work on every other brand of tank

Try National energy they are on line .

replace it about $20.00 for part amazon eBay


http://smartmoneymd.com/replacing-the-flammable-vapor-sensor-in-your-hot-water-heater

You can reset some models.... depending on gas control valve and FVIR design.
Some newer models you replace the sensor located on outside of tank.
http://waterheatertimer.org/How-to-troubleshoot-gas-water-heater.html#intellivent
http://waterheatertimer.org/How-flammable-vapor-sensor-works-Therm-O-Disc-25VS.pdf

Gene

If you need further help, I’m available over the phone at https://www.6ya.com/expert/gene_9f0ef4df2f9897e7

You can't bypass a flammable vapour sensor. it works on resistance not continuity. You can try moving the sensor outside for a while and it may reset itself...meaning that the resistance may fall back within range. You are best to have the sensor replaced by a qualified technician who can also verify that you do not have an underlying issue such as a gas leak which is causing the sensor to trip.

Your safety device is probably sensing humidity as vapor. That's what ours seems to do. The replacement FVD is Rheem AP13447-3 Flammable Vapor Detection Sensor. It's down near the floor, can be pried off with a screwdriver, and unplugged. It needs to be replaced, since the heater will not ignite if its unplugged or too high resistance (detecting gas, or, if broken, moisture after a rain).
http://www.amazon.com/gp/product/B007IB22NM

Certain 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. I'm not sure what control your unit has, but on a White Rodgers here's how it goes.


White Rodgers Intelli-Vent PowerVent Control Equipped Models

1. Step 1 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).
   
2. Step 2 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.
   
3. Step 3 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

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

1. Step 1 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).
   
2. Step 2 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.
   
3. Step 3 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

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
1. Step 1 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).
   
2. Step 2 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.
   
3. Step 3 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).