Water Heater Pilot Outage


  #1  
Old 12-21-03, 10:00 AM
puji
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Gas waterheater pilot light goes off .

A couple off days ago I discovered that the pilot light was off and it smelled like gas. I discovered, that the pilot light does not switch off after going off. I guess the thermo coupling is bad and needs to be replaced. Is this also connected that the pilot light turns off easily? The heater is about 13 years old.

thanks
puji
 
  #2  
Old 12-21-03, 10:17 AM
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Lightbulb water heater

If the pilot went out and it still let the gas out the pilot Id say the gas valve is whats bad also .13 years on the tank It might pay to get a new one rather than a new gas valve ED
 
  #3  
Old 12-21-03, 10:28 AM
puji
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Thank you for the prompt reply. It is a 50 gal heater and the new ones are probably round $400 to $500. So I want to see weather it is that serious.
I checked more and the gas supply for the pilot turns offt after about a minute. What is a reasonable time to shut off? I also do not know weather it might take longer at other times because I smelled gas before but not now testing it

puji
 
  #4  
Old 12-21-03, 10:35 AM
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Lightbulb water heater

Well you can try the T/C cost about $5 Take the one with you so you get the right kind. But Id keep an eye on it if the valve didnt shut off the pilot for sure.So check it out ok ED
 
  #5  
Old 12-21-03, 10:46 AM
puji
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Thanks again. I will try that, but there is still that question . If the thermo coupling is defect, can it cause the pilot light to switch off at random or can there be other reasons? I lived in this house for about ten years and it never happened before. The flame looks ok and large enough and I will take it the pipe out and and clean it when I replace the themo coupling. But it is important to find out why it is happening.

Thanks

puji
 
  #6  
Old 12-21-03, 07:56 PM
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Hello: puji

When the pilot is extinguished, the delay before the safety shuts down can be up to 1 to 2 minutes. That time is called dropout time. Perfectly normal up to that time.

Any amount ofter that, suspect a problem. Especially if the drop out time lasts more than 2 minutes. Or the pilot gas continues to come out when the flame is out past that 2 minutes.

Dropout time can be measured using any watch with a second hand. Extinguish the pilot flame and count the seconds watching the seconds hand on the watch.

If you listen closely and there are no area noises, you'll hear the tiny ping of the metal cap inside the control snap shut. That has to happen within not more than 2 minutes.

If the ping is heard within 60 seconds or less, the thermocuple is weak. If the ping is not heard at all or the pilot gas continues to escape after 2 minutes, the internal safety is not shutting down.

The cause of the problem, when the safety does not drop out after 60 seconds and not more then 2 minutes, is the safety valve inside the control is defective.

There is no repair that is safe nor repair that is possible. The entire control must be replaced. Doing so ensures the burner shuts down too.

If the pilot gas continues to come out after the time mentioned above, so is it very possible the burner gas will also when the thermostat calls for heating the water.

The safety the pilot shuts down when the pilot goes out also shuts down the burners gas valve. In many cases when the pilot goes out but the pilot gas still comes out after 2 minutes, so will the burner gas.

Which prsents a danger of fire and or explosion, just waiting to happen. Burner gas will fill the firebox, escape up the flu and some may spill out in to the area around the tank. Any source of ignition will set it off.

If tank replacement cost is a factor at this time, replace just the control. Failure to do so, is allowing danger to exist, a risk of fire danger and or explosion danger.

Regards & Good Luck. Sharp Advice
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Last edited by Sharp Advice; 12-21-03 at 08:22 PM.
  #7  
Old 12-21-03, 10:11 PM
puji
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Thank you for the detailed information. This is very helpfull. I allready measured it and it is 60 second. I still have to look into why I smelled gas, because with this shut off time I do not smell gas.
It is still possible that the unit started randomly not to shut off in time . So I have to watch that. The problrm is, if the fault is not present, how can I detect the problem? I did blow out the flame several times , no problem. I also think that the flame blew out in the first place, because it was relit after a gasline shut off and the cover was not put on right and fell over, so a strong brise could have blown it out. Any more suggestions?

puji

P.S. I will watch it very closely for a while
 
  #8  
Old 12-22-03, 05:55 AM
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Hi: puji

With a control that has been in use 13 years anything such sa you describe is possible and I think I have encountered them all. Ramdom and or sporadic conditions are always hard to diagnose and harder still to locate.

Based on the age of the water heater, it is always possible there is a tiny water leak inside the firebox. If the is any signs of rust anywhere, it's an indication of a pinhole water leak. The start of a bigger problem developing.

If such is visable and or evident, the water droplets may also be visable when the burner has been on after several minutes. The steel begins to expand from the heat, opens a seem in the flue and mist or tiny droplets appear.

Often the drops are directly over the pilot assembly. The water puts out the pilot not wind, etc. Misleads one to think it is a thermocouple problem, safety device problem, magneto problem, etc.

Look closely at the firebox and into the firebox. Be sure the control will not allow the burner to fire up during the inspection process. Rust and or scale is an indication it is time to begin planning on buying a tank replacement.
 
  #9  
Old 12-22-03, 09:33 AM
puji
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Hi Sharp Advice,

Good hint. I will check on that.

Thanks

puji
 
  #10  
Old 12-22-03, 02:32 PM
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Hi: puji

Forgot to mention that it is often possible to visually see the water dropping down into the firebox. Usually happens when the water inside the tank is cold.

Shortly after the burner fires up, water droplets can be seen if the outer and inner covers are removed from the firebox. The sound of hissing may also be heard as the water hits the burner and evaporates.

If enough water comes down onto the pilot, it will extinguish the flame. If the water drops away from the pilot flame, it will hit the burner only causing yellow flames and hissing sounds.

Neither are good signs. Water heater replacement is the only solution.

Post back the results of your findings. In doing so all readers of this questions will learn from it. Sharing is how we all learn.
 
  #11  
Old 12-22-03, 03:41 PM
puji
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Hi Sharp Advice,

I checked the box. There is no sign of water anywhere. The outer hull is a liitle bit oxydised but more in the orange color. You could easily whipe it off and see the metal but there are nor real rust spots (dark brownish, flaky). The same with the rest except the burner. But i think this is due to (rare) condensation in the flue dripping down on the burner. I hear the noises you were talking about occasionally, that means about twice a year. I am living in the desert and usually it is pretty dry.

Thanks for your input

puji
 
 

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