# Need input on AO Smith



## panther (Oct 27, 2010)

40 gallon natural gas AO Smith. Heater is about 9 years old. Still in good condition. Customer calls and says no hot water. I tried to light and pilot did stay lit. However, milivolt reading was very eratic on thermocouple. The thermocouple has one of those discs in between the tip and where it connects to the control valve. There was a crack in that disc. So, the supply house orders me a complete burner assembly. The control valve had a bunch of dirt and tiny specs of paint on it. So I got a new control valve for it too. Cleaned the inside of combustion chamber very well. Used my tiny vacuum brush to clean air intake at bottom of heater. Also, used compressed air to clear it. Re assembled everything and pilot will go out after the heater has reached the desired temp and burner has shut off. It will stay lit for about 3 minutes, then slowly fade and shut off. One time after burner had been on for about 5-7 minutes, it shut off immediately. I have checked flame. Flame and pilot flame are blue and steady. Draft throughf vent is good. Fresh air vent in garage not blocked. What am I missing? Any help would be appreciated.


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## panther (Oct 27, 2010)

Also, re checked milivolts on new thermocouple to make sure it wasn't faulty out of the box.


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## Epox (Sep 19, 2010)

I carry a small compressor with me at all times. I have a 18" piece of 3/8 copper tubing with a small 90 bent into end and crimped tip to act as a nozzle. From combustion chamber I BLOW compressed air through intake screen forcing dust lint etc backwards out of the screen. Then vacuum and replace or install new pilot assembly.


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## Cajunhiker (Dec 14, 2009)

Troubleshooting ideas
1. You cleaned the air intake inside the combustion area. Clean under the tank also. Attach a piece of 3/4" PVC pipe with a 90 on the end, and Duct tape other end to your shop vac hose. Vacuum the intake from under the water heater.
2. Take the flue apart and clean inside with a rag. Soot and moisture may be dropping down into the combustion area. 
3. Check the obvious, like making sure there are no obstructions in the gas supply line and that the gas valve is open all the way.


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## sierra2000 (Sep 19, 2011)

New water heater


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## dclark (Dec 12, 2010)

I’d be tempted to stick my manometer on it, to check inlet pressures while it’s firing and see if you can catch something when it goes out.
I have seen gas meters and regulators do some pretty strange things.


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## panther (Oct 27, 2010)

dclark said:


> I’d be tempted to stick my manometer on it, to check inlet pressures while it’s firing and see if you can catch something when it goes out.
> I have seen gas meters and regulators do some pretty strange things.


Yeah. That's what I'm going to do next. The funny thing about this situation is the water heater is the only fixture that uses gas in the house. Water heater is in garage. 1/2" line straight from the meter about 35' away.


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## plumbdrum (Nov 30, 2013)

sierra2000 said:


> New water heater


I agree, at 9 years old, not worth sinking any money into it with parts and labor. That being said, still good trouble shooting about the topic.

Sent from my iPhone using PlumbingZone


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## Epox (Sep 19, 2010)

An AO Smith lasting 9 years is unheard of anymore.


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## panther (Oct 27, 2010)

Update. When burner first fires I'm getting 3.9" of water column. When it's close to the desired temp it drops to 3.8". Is this normal? Psi was 1.147.


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## panther (Oct 27, 2010)

Correction. Psi 0.147.


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## UN1TED-WE-PLUMB (Oct 3, 2012)

panther said:


> 40 gallon natural gas AO Smith. Heater is about 9 years old. Still in good condition. Customer calls and says no hot water. I tried to light and pilot did stay lit. However, milivolt reading was very eratic on thermocouple. The thermocouple has one of those discs in between the tip and where it connects to the control valve. There was a crack in that disc. So, the supply house orders me a complete burner assembly. The control valve had a bunch of dirt and tiny specs of paint on it. So I got a new control valve for it too. Cleaned the inside of combustion chamber very well. Used my tiny vacuum brush to clean air intake at bottom of heater. Also, used compressed air to clear it. Re assembled everything and pilot will go out after the heater has reached the desired temp and burner has shut off. It will stay lit for about 3 minutes, then slowly fade and shut off. One time after burner had been on for about 5-7 minutes, it shut off immediately. I have checked flame. Flame and pilot flame are blue and steady. Draft throughf vent is good. Fresh air vent in garage not blocked. What am I missing? Any help would be appreciated.


Look how much this customer has invested in a 9 year old water heater. It shouldve been replaced.


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## Shoot'N'Plumber (Apr 27, 2013)

UN1TED-WE-PLUMB said:


> Look how much this customer has invested in a 9 year old water heater. It shouldve been replaced.


I agree, however, the water column going through a brand new control valve may indicate inadequate gas supply coming from main regulator. most w/h I believe require 5" wc min. So I would test the main as it comes outa the regulator.


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## Steveking (May 16, 2014)

I usually clean the combustion chambers with water on the older AO smiths and compressed air and the brush method.


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## rjbphd (Feb 5, 2010)

Steveking said:


> I usually clean the combustion chambers with water on the older AO smiths and compressed air and the brush method.


Who are you to say this without posting proper intro??


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## panther (Oct 27, 2010)

UN1TED-WE-PLUMB said:


> Look how much this customer has invested in a 9 year old water heater. It shouldve been replaced.


I'm with you on that. This is for a property management co. They always want repair before replace. Normally, a water heater of this age and depending on condition, it gets replaced. On this one, I thought a repair was reasonable. But there is definitely a little more time on this repair than I thought it was going to be.


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## panther (Oct 27, 2010)

Update. Problem solved. Re directed my focus back to the thermocouple on the new burner assembly. The reading I was getting was around 27.7 milivolts. I decided to leave the meter on it for a while to see what would happen. After about 7 minutes, the milivolts would begin to decrease. Pilot flame stayed the same size and steady. It eventually went down to around 10 milivolts. Replaced burner assembly again. Problem solved. I never expected that to be broken right out of the box.


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## Cajunhiker (Dec 14, 2009)

panther said:


> Update. Problem solved. ... Replaced burner assembly again. Problem solved. I never expected that to be broken right out of the box.


Nice catch. None of us would expect the burner assembly to malfunction right out of the box. Now we know at least it is one of the many possibilities for not keeping a flame.


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## Master Mark (Aug 14, 2009)

you really went way beyond the extra mile with that 9 year old water heater...

I was going to tell you to change out the gas valve because it 
sounded like the high limit shutting it down to me.

I hope that you dont get a call from them again in a few days saying its gone out again...if it does, that is what I would throw out the door next..



So...How much did the customer get charged???


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## sparky (Jan 8, 2014)

panther said:


> Update. Problem solved. Re directed my focus back to the thermocouple on the new burner assembly. The reading I was getting was around 27.7 milivolts. I decided to leave the meter on it for a while to see what would happen. After about 7 minutes, the milivolts would begin to decrease. Pilot flame stayed the same size and steady. It eventually went down to around 10 milivolts. Replaced burner assembly again. Problem solved. I never expected that to be broken right out of the box.


Yes I agree with Cajun,nice catch but wait a few days before you bill them to make sure it don't act up again


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## sparky (Jan 8, 2014)

panther said:


> 40 gallon natural gas AO Smith. Heater is about 9 years old. Still in good condition. Customer calls and says no hot water. I tried to light and pilot did stay lit. However, milivolt reading was very eratic on thermocouple. The thermocouple has one of those discs in between the tip and where it connects to the control valve. There was a crack in that disc. So, the supply house orders me a complete burner assembly. The control valve had a bunch of dirt and tiny specs of paint on it. So I got a new control valve for it too. Cleaned the inside of combustion chamber very well. Used my tiny vacuum brush to clean air intake at bottom of heater. Also, used compressed air to clear it. Re assembled everything and pilot will go out after the heater has reached the desired temp and burner has shut off. It will stay lit for about 3 minutes, then slowly fade and shut off. One time after burner had been on for about 5-7 minutes, it shut off immediately. I have checked flame. Flame and pilot flame are blue and steady. Draft throughf vent is good. Fresh air vent in garage not blocked. What am I missing? Any help would be appreciated.


First thing I would do is beat the ****zu out of the gas valve with a pair of channel locks,works for mark lololololololo I had to post that


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## Master Mark (Aug 14, 2009)

sparky said:


> First thing I would do is beat the ****zu out of the gas valve with a pair of channel locks,works for mark lololololololo I had to post that


 

you are mis-quoting me .....

I only smack the ICON valves....... 

NEVER do I hit the older style robert shaw valves
it dont do no good at all.....:no::no:


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## sparky (Jan 8, 2014)

Master Mark said:


> you are mis-quoting me .....
> 
> I only smack the ICON valves.......
> 
> ...


uh oh,sorry,only beat the crap outta the icon valves,my bad,them older valves are solid,may have to graduate up to a claw hammer.:thumbup::thumbup::laughing:


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## panther (Oct 27, 2010)

sparky said:


> First thing I would do is beat the ****zu out of the gas valve with a pair of channel locks,works for mark lololololololo I had to post that


It's funny. I was thinking about that when I started with this. It lightened the mood up for me. Haha.


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## dhal22 (Jul 30, 2010)

Master Mark said:


> So...How much did the customer get charged???




this is the important part.


David


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## dhal22 (Jul 30, 2010)




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## Best Darn Sewer (Dec 23, 2012)

rodeorooter said:


> A.O. Smith BTR-120 Commercial Tank Type Water Heater, Natural Gas, 71 Gallon, Master-Fit, 120,000 BTU Input can be so well-made. In fact it is not only you will definitely remember to on this great conceiving and also you will meet while using the affordable price tag should you equate to the opposite related merchandise and that is on the internet around the world. That piece is covered along with the perfect substance in addition to really modern method that our skills maker did concur along with authorize to produce this kind of greatest item for our customer and you.


What? Its written in English but I am lost with what you wrote...


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## SchmitzPlumbing (May 5, 2014)

when people talk the way he types i refer to them as marble mouth. how many marbles do you have in there? spit them out and try talking normal.:blink:


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## plbgbiz (Aug 27, 2010)

SchmitzPlumbing said:


> when people talk the way he types i refer to them as marble mouth. how many marbles do you have in there? spit them out and try talking normal.:blink:


Elvis has left the building.


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## Gargalaxy (Aug 14, 2013)

Something like this?.......


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## titaniumplumbr (Jun 11, 2014)

Ha ha I think someone has been plagiarizing the Japanese to English owners manual again


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