Hot Water Tank Flammable Vapor Sensor Lockout - A.O. Smith - Promax

taviyo

After recently painting my basement floor I discovered to my surprise that I had no hot water. After doing some investigating on my hot water tank, it was revealed that the hot water tank had placed itself in a lockout due to detection of flammable vapors by the FVIR sensor, caused by the drying solvent based concrete floor sealant. Unfortunately, my manual gave me only directions to contact my nearest service center as a solution for this error code and the A.O. Smith troubleshooting hotline was outside of regular business hours (I believe they do not list a reset procedure in the manual because of liability issues associated with a homeowner attempting to bypass the flammable vapor sensor when there is the possibility for enough flammable vapors to constitute an explosion). I was just painting my floor, there was no chance for any explosion and I need hot water SO, I will post here the solution that I couldn't find anywhere else in hope that others will not have to experience this frustration if they find themselves in a similar circumstance.

Please ensure your basement/mechanical room is well ventilated during this process. Use at own risk.

-Locate the FV sensor at the bottom of the tank located inside grey plastic clip box.

-Turn power off to hot water tank.

-Remove sensor by disconnecting both spade connectors and place in well ventilated area for 4 hrs (Mine reset itself in 1.5 hrs).

-BYPASS SENSOR -
(Only do this if you are certain vapor level is below any possibility for explosion and you must get your hot water tank working)

Place the sensor inside a sealed plastic ziploc bag and push the two spade connectors through the plastic thus sealing the unit off from the fumes.
-OR-
Insert equivalent series resistance between 70,000-1,700,000 ohms.

-Replace sensor on hot water tank.

-Cycle power ON.

-Depress both left and right arrows for 5 seconds until vacation light flashes.

-Again depress both left and right arrows for 10 seconds until all lights are lit.

Your hot water tank should now release the lock-out and normal operation should resume. If your hot water tank does not resume it may be an indication of FV sensor failure. Ensure the fully vented FV sensor has a resistance of 70,000-1,700,000 ohms.

JerryKo

i have 2 gas hot water heaters and one electric one in my 3 unit apt building.
the flammable vapour sensors have gone off 3 times each in my gas heaters in the last year... that is 6 sensors in a room that only has furnaces and hot water heaters, and 4 spare car tires.
can i do anything to prevent this from happening? my plumber that comes in charges me around $170 each time he comes in, and he doesnt smell any flammable vapours, nor do I. the plumber doesnt know what the problem could be, he doesnt have these issues with the same hot water heaters in other buildings, just mine. it doesnt happen on the air heaters, just the hot water heaters.

any suggestions from anyone?

taviyo

JerrkyKo,

I believe that flammable vapors are causing your issue and your plumber is not helping you by doing a reset on your tanks. Plumbers like this guy make small fortunes on resetting these FV sensors as they are quick and easy fixes with a large house call bill. I would suggest finding someone more interested in fixing your real problem which is most likely a leaking gas fitting(s). At the very least, more properly ventilate your utility room and find out how to do the reset on your tanks yourself to save yourself the $170 headache.

T

gsoccer17jd

Thanks for the info on resetting this sensor. After returning from vacation, the key board lit up w/3 lights after I attempted to turn the tank back on. The instruction manual stated it was a FV Sensor. I checked for gas leaks and all was OK. It worked great. I removed the switch and waited 90 minutes after setting it outside. - reassembled and it started on the 2nd attempt. Thanks again-!!!!!!

DIY_novice

Thank you TAVIYO !! Like you, I had been painting in my basement with oil-based paint (painting walls). I even had the windows open. Next day, no hot water! Not so helpful manual says to call qualified repair person. Yes, I can see point (it is a huge safety issue after all) . . . but still. Tried resetting myself by unplugging and plugging back in. Did not work.

A friend found your post. You saved me $165 in labor ($65 "diagnostic charge" + minimum $100 trip charge). They also were quoting me an additional $100 to replace the FV Sensor.

So THANK YOU again !!

taviyo

You can make the cheque out to taviyo PO Box 12345

That's fantastic, I'm glad I posted this solution here as I'm sure there are alot more people that this has helped that haven't posted responses.

LarryM

Well this is just fantastic
I also painted my basement with oil based paint on Sunday with the window open but it being early March I had to close the window because it is cold. I also cleaned my brush and roller in mineral spirits which I left in the pan for about 4 hours. (not the brush and roller)

Well come Tuesday morning no hot water...WTF
I get home tonight from work and school and still no hot water so I decided to read my owners manual after I see odd lights on the control panel. (the house stinks from the paint and mineral spirits)...the manual shows it is locked down because of the vapors

Glad I found this post. Last time I will use oil based paint and mineral spirits in the basement. Now I have to let everything air out and try the OPs method and pray I have hot water tomorrow night. Cold shower tomorrow morning

Also found this on the internet. Helpful for AO Smith units with Intelli-Vent gas control

LarryM

FYI the method I listed with the reset steps worked perfectly