Question about RTO W4 A.O Smith Gas Hot Water Heater Draft Inducer

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Gvr 40 100 will not stay lite - RTO W4 A.O Smith Gas Hot Water Heater Draft Inducer

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The Cold air screen on the bottom of the water heater is partially plugged. That is if the pilot light can be lit and stay on, but goes out when the heater should be functioning normally. This is not the removable plastic screen but a round white-yellow grid with 1/32" holes. You can try to clean it through the bottom but you may have to remove the gas line from the controller to the burner, pilot gas line, and thermocouple connection to remove that complete assembly to get access to the screen. The AO Smith booklet warns of this but they pretend the plastic screen will keep this second screen clean but it won't. After three years it was two thirds plugged.

Posted on Jul 10, 2010

  • bronze508 May 31, 2011

    Thanks for the info :) I ended up blowing out the bottom screen with my air compressor and had the vacuum right there sucking up the dust. after a couple of minutes it was cleaned out. I fired up and it stayed lit. Really glad too because trying to change out the thermocouple was going to be a hassle on this unit. Everything is working great now.


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Change out the thermocouple. if that doesnt work, check the gas pressure checked.

Posted on Dec 13, 2009

  • Info009 Jan 15, 2011

    I'm no expert or plumber, but we were experiencing a similar problem. Here's what helped us, and hopefully this will help you!

    We have an ao smith gcv 40 100 water heater at our house, and just recently our 3 year old water heater's pilot light kept going out. It would stay lit enough to heat up one cycle, but seemed to go out after the burner was done warming up the water. I called a plumber and had the thermocouple piece replaced since I didn’t feel comfortable replacing the piece myself, which was pretty expensive (about $180, mainly since he had to order the parts from ao smith plus service fees). But replacing the thermocouple device didn't help the problem, and an hour after it was installed the pilot light went out again. After searching many forums, it seems that ao smith closed system water heaters are known to have difficulty with the filter getting plugged up not allowing enough air through to allow the pilot light to stay lit. My personal theory for our problem was that after the burner went out, the blocked filter wouldn't let the air out from the gust of the burner extinguishing which blew out the pilot light (or the filter didn't allow enough air in to keep the pilot light on).

    The filter for our water heater is about an inch off the ground located in the middle of the heater, and it's approximately a one foot diameter circular screen. If you take off the air intake screen at the very bottom (looks like a black plastic strip with holes about a foot long), grab a mirror and a flashlight, you can see the circular filter underneath the water heater.

    I’ve also read on forums saying that a shop vac that can blow air out is also helpful in cleaning the filter, but I do not own one of these, plus my vacuum doesn’t have that feature. Anyway, what I did was went to a department store (I went to Lowe’s but Home Depot will have these), bought a 1/2" 5' pvc pipe (couldn't find a 1/2" pvc pipe that was 2 or 3 feet long) for only $1.19. I had also bought a 1/2" elbow for the pvc pipe that cost $0.45 thinking it would help my vacuum the filter, but the elbow was too big and would not swivel under the water heater between the floor and the filter so I couldn't vacuum directly on the filter. I made an approximately 1" x 1" x 1" box out of cardboard and duct tape leaving one side open. With the open side facing up, I cut 2 edges to open one of the sides like a flap, then taped the flap to the pvc pipe. I then used duct tape and taped the other end of the pvc pipe to my vacuum where it allows attachments. That allowed me to stick the pvc pipe under the water heater and vacuum directly up against the filter. After vacuuming the filter, our water heater finally has been working great after we’ve endured 2 weeks of constantly lighting the pilot and having to wait 15 minutes for the water to heat up before one person could shower!

    You can also find the manual for AO Smith gas water heaters here, but the manuals are not very helpful for troubleshooting since majority of the problems it’ll tell you to contact a service agency.

    Hope this helps! And hopefully your problem isn't the thermocouple but the filter like ours and this $2 fix will save you a couple hundred dollars!




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SOURCE: gas pilot wont stay on

they are universal, the only thing youi need to know is how long it should be, most will take a 30inch, just to make sure you have enough, our oyu can take the one out that you have and match it up, the one you take out will actually measure a little shorter then the new one which is ok, just make sure you put the burner assembly back in the perch correctly, if not you will have bigger problems then you want to have

Posted on Jun 28, 2009

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