Pilot won't stay lit on AO Smith Water Heater

[gossamer]

Hi, first post to the forum. I'm a relatively handy homeowner/DIY. We have an AO Smith 50gal gas water heater that's at least twenty years old. This morning I noticed the hot water faucet was cold. I went to the water heater and did not hear any gas/flames and could not see the pilot through the view port, so I went through the procedure to try and restart the pilot.

Even while striking the ignitor, I could not see anything through the view port, but after turning the knob from Pilot to On, the gas did fire and it started to heat the water again. At least for a few hours. It only reached a lukewarm temp before apparently going out again, and now it doesn't appear to start at all.

What are my next steps? Here are two pictures with the model info and what the access panel looks like. Any ideas greatly appreciated. Obviously we'd like to get this working as quickly as possible.

 

[breplum]

Seeing the ignitor spark is very tricky. You have to know where to look.
Clear any inlet screens. Clogged screens are a common problem.
It is hardly worth doing anything more except replace the WH since it is soooo old.

 

[BlueSkyHigh]

A lack of proper airflow could be causing the pilot flame to be weak and not able to keep the thermocouple hot enough to keep things operating. To that end, when was the last time that the air filter screens around the bottom of the tank were vacuumed clean? Also, depending on your level of expertise and desire, you could remove the burner/ignitor assembly and clean/burnish the thermocouple assembly that generates the tiny amount of electrical energy that keeps the pilot light energized while ensuring that the pilot light thermocouple is still in the center of the pilot light. Of course that requires you to turn off the gas supply and remove the appropriate fittings, etc.

But, as mentioned by @breplum, you definitely got your money's worth out of the water heater and it should probably be replaced.

 

[gossamer]

A lack of proper airflow could be causing the pilot flame to be weak and not able to keep the thermocouple hot enough to keep things operating. To that end, when was the last time that the air filter screens around the bottom of the tank were vacuumed clean? Also, depending on your level of expertise and desire, you could remove the burner/ignitor assembly and clean/burnish the thermocouple assembly that generates the tiny amount of electrical energy that keeps the pilot light energized while ensuring that the pilot light thermocouple is still in the center of the pilot light. Of course that requires you to turn off the gas supply and remove the appropriate fittings, etc.

But, as mentioned by @breplum, you definitely got your money's worth out of the water heater and it should probably be replaced.

Thanks so much for your help.

Given it's 20 years old and really should be replaced, will the new one be a drop-in replacement? I thought I remembered something about no longer being able to use the chimney flue to send the exhaust here in New Jersey?

Do I need a pump to pump the water out, given the water heater is in our basement and is probably already at the lowest point? I believe the street level may be a bit lower, so it's possible I could connect a hose and run it to the street to drain, but I may need a pump to get it started.

Perhaps you know of a youtube how-to video to explain what I need to know?

 

[BlueSkyHigh]

Do I need a pump to pump the water out, given the water heater is in our basement and is probably already at the lowest point? I believe the street level may be a bit lower, so it's possible I could connect a hose and run it to the street to drain, but I may need a pump to get it started.

Because your water heater is installed in the basement, I suspect that there must be a drain somewhere in the vicinity covered by a grate in the floor to dump the water should a leak or catastrophic failure of the water heater occurred that you could run the hose from the drain on the bottom of the water heater into or possibly there is a sump with a pump in it to take care of a flooded basement?

 

[gossamer]

Because your water heater is installed in the basement, I suspect that there must be a drain somewhere in the vicinity covered by a grate in the floor to dump the water should a leak or catastrophic failure of the water heater occurred that you could run the hose from the drain on the bottom of the water heater into or possibly there is a sump with a pump in it to take care of a flooded basement?

I don't think there is a drain anywhere. It would be really nice to have a sink in the basement, there's no sump pump or other drain.

However, it's not necessary, at least for now, BECAUSE I FIXED IT!!!

I was able to pull out the heating assembly, clean off a significant amount of rust that had deposited on top of the burner, vacuum it all out, and put it back together. I'm now confident that was the problem, so at least we have a reprieve for a while and my wife can take a shower without having to go to her parents, lol.

We'll still keep the appt with the plumber to see what they propose.

Thank you all!

 

[gossamer]

Okay, looks like I spoke too soon :-(

The pilot and burner stayed lit for about ten minutes, but again went out, even after thoroughly cleaning it.

What else could cause this? Is it possible cleaning the valve here would help?




The burner itself looks to be in fine shape.

 

[BlueSkyHigh]

Take some light sandpaper or emery cloth and clean the thermocouple off. It's the piece of metal coming out of the white insulator. It looks atrocious and it should be shined up! If you really want to keep the water heater going, consider replacing the thermocouple. By the way, the burner is is the big round thing from which the main fire comes from when the water heater is heating and not the pilot light assembly.

 

[gossamer]

Take some light sandpaper or emery cloth and clean the thermocouple off. It's the piece of metal coming out of the white insulator. It looks atrocious and it should be shined up! If you really want to keep the water heater going, consider replacing the thermocouple. By the way, the burner is is the big round thing from which the main fire comes from when the water heater is heating and not the pilot light assembly.

Okay, I have cleaned the thermocouple, but now it doesn't start at all :-(

I can see the pilot is lit, but the burner doesn't ignite after starting the pilot and turning the dial on top to "ON". Perhaps I damaged something?

Here's what it looks like now:



Also, I was referring to the actual top side of the burner previously:


Any idea what I might have done wrong? If I need a thermocouple, it looks like this is the assembly I need for an AO Smith PVR-50-100?
https://www.amazon.com/Assembly-Replacement-Compatible-100109295-9003542005/dp/B09W6553LK/

 

[BlueSkyHigh]

Make sure you’ve turned the thermostat up to the hot enough. If the pilot’s on you didn’t do anything wrong with respect to cleaning the thermocouple.

 

[gossamer]

Make sure you’ve turned the thermostat up to the hot enough. If the pilot’s on you didn’t do anything wrong with respect to cleaning the thermocouple.

The thermostat is definitely high enough. The water is now cold.

And I'm thinking it must have something to do with the thermocouple, considering it at least started before cleaning it. I'm going to try and clean it out again and wait until the new assembly arrives tomorrow.

 

[BlueSkyHigh]

Cold showers suck! AFAIK, the thermocouple does nothing more than to produce the tiny amount of electricity that keeps the valve to supply gas to the pilot light and not the main gas burner assembly. It's the thermostat that controls the flow of gas to the main burner. Once again, if the pilot light remain lit then the thermocouple is doing its job.

 

[gossamer]

Cold showers suck! AFAIK, the thermocouple does nothing more than to produce the tiny amount of electricity that keeps the valve to supply gas to the pilot light and not the main gas burner assembly. It's the thermostat that controls the flow of gas to the main burner. Once again, if the pilot light remain lit then the thermocouple is doing its job.

okay, thank you. Is it possible I somehow damaged one of the lines when reassembling it?

I'm trying to figure out what could have happened between the time where it ran for about ten minutes to now where it doesn't run at all, with the only difference being just removing the assembly and cleaning it. Maybe the valve is now clogged or something?

 

[MicEd69]

As others have said, if the pilot light is lit, and the controls are set to provide hot water, and the water heater burner doesn't come on, the gas valve/controls may very well be the problem. A water heater that can vote in the presidential election next year should be replaced. I wouldn't be spending good money after bad if it were mine.

 

[BlueSkyHigh]

A water heater that can vote in the presidential election next year should be replaced. I wouldn't be spending good money after bad if it were mine.

Thanks for that!

 

[gossamer]

As others have said, if the pilot light is lit, and the controls are set to provide hot water, and the water heater burner doesn't come on, the gas valve/controls may very well be the problem. A water heater that can vote in the presidential election next year should be replaced. I wouldn't be spending good money after bad if it were mine.

Yes, very funny

So as it turns out, it's working! I'm so dumb. I think I underestimated just how long the tank keeps the water warm, because when the burner never started, I never even thought it was because the water was already at temperature. I was watching it the whole time.

This was always about keeping it going long enough until we can replace it in a more scheduled way.

Thanks every for all of your help. Hopefully it truly is resolved now, but I'll be back when I try and replace it myself in a few weeks

 

[arctic bill]

A lack of proper airflow could be causing the pilot flame to be weak and not able to keep the thermocouple hot enough to keep things operating. To that end, when was the last time that the air filter screens around the bottom of the tank were vacuumed clean? Also, depending on your level of expertise and desire, you could remove the burner/ignitor assembly and clean/burnish the thermocouple assembly that generates the tiny amount of electrical energy that keeps the pilot light energized while ensuring that the pilot light thermocouple is still in the center of the pilot light. Of course that requires you to turn off the gas supply and remove the appropriate fittings, etc.

But, as mentioned by @breplum, you definitely got your money's worth out of the water heater and it should probably be replaced.

I would change the thermocouple and see what happens

 

[Twowaxhack]

I would’ve cleaned the burn chamber, replaced the thermocouple and cleaned the pilot orfice and recommended replacement at first opportunity.

Standard procedure……

The burn chamber door seal would also need to be replaced.