TriancoGas faulty valve?

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  #1  
Old 02-03-03, 02:19 AM
AH30
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Question TriancoGas faulty valve?

Hi, I wonder if someone can help with what, I hope, is a simple (newby) problem.

I have a TriancoGas 25/45 boiler. The pilot light stays lit as long as I keep the 'starter' button pressed. As soon as I let it go, the pilot light goes out and there is a click from one of the boxes inside the boiler.

I have replaced the thermocouple and I still have the same problem.

Does anyone have any idea what i can try next? I have been looking around on the net for advice and there may be some suggestion that it could be a faulty gas valve. Does this sound feasible?

Thanks in advance.
 
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  #2  
Old 02-03-03, 02:44 AM
bigjohn
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You might have a bad gas valve, but first it would be useful to check the strength of the millivoltage produced by the thermocouple. The pilot burner flame may be insufficient. Does the pilot flame envelop about 3/8" to 1/2" of the END of the thermocouple?
 
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Old 02-03-03, 02:53 AM
AH30
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Thanks for the reply bigjohn.

I will try and check the voltage produced by the thermocouple. The flame does cover the end 1/2" of the thermocouple.

Something that my wife has just reminded me of. Over the last couple of months, once or twice, the heating has cut out (pilot light and main burner) when the boiler is 'fired-up'. Again, with one of those clicking sounds. Does this narrow it down?

Thanks
 
  #4  
Old 02-03-03, 07:18 AM
bigjohn
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The click noise may be coming from the safety relay inside the gas valve dropping out. The process starts with the pilot burner staying lit. Without that nothing else will happen. The thermocouple should produce 23 to 28 millivolts open circuit if you have a good thermocouple, good pilot flame, and proper postioning of the pilot flame.
 
  #5  
Old 02-03-03, 08:00 AM
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Are you sure??

You have a Thermocoupleh, and not a heat rod?


The clicking sound, do you have spark going by the pilot?

Some older furances has standing pilot with spark, and the rod is a thermomotir (SP) and when the pilot lights, the rod gets warm, and then wen it is warm, the gas valve will open
 
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Old 02-05-03, 04:36 AM
AH30
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Thanks for the continued help.

On my system the pilot safety switch is a seperate device from the gas valve and this seems to be where the clicking is coming from. The thermocouple produces 21mV. Is this enough? the pilot light will not stay lit.

It is definitely a thermocouple and there is a spark.

On the advice of a friend, I shorted out the swich by connecting the two wires together that lead to the safety switch - voila, it works. Does this mean that the problem is definitely with the switch or am I missing something? I have let the house warm up and then I have put the cables back in their proper places - I really don't want to blow myself up!!
 
  #7  
Old 02-05-03, 08:14 AM
bigjohn
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Now we're confused and need to nail down the type of ignition system you have. You're saying there is a thermocouple and a spark? What do you mean? Do you have a spark module that lites the pilot or is it a manually lit pilot? The end of the thermocouple that is not in the pilot burner- where does it go? To the safety switch you jumpered? How old is the boiler? it sounds like you're describing an old boiler with a multi component gas train. The thermocouple would screw into the pilotstat safety control and the wires from the gas valve would be in series with the pilotstat safety control. Is the 21mv open circuit or closed circuit? Open circuit means disconnected from the pilotstat safety control. Normal range is 26 to 32 millivolts open circuit. Lowest acceptable is 18 millivolts. If that is an open circuit reading, try cleaning or replacing the pilot burnerand see if the MV increases. Can you find a brand name and model # on the pilotstat safety? It's probably Honeywell, White-Rodgers or Penn/Baso.
 
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Old 02-06-03, 01:25 AM
AH30
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Sorry, it seems my ignorance is showing. It is a manually lit pilot. the end of the thermocouple that is not in the pilot does go to the safety switch.

The boiler is 10 years old. The 21mV is an open circuit reading. I have now cleaned everything and the reading has gone up to 23mV.

I cannot find a brand name on the pilot safety switch. It is just a plain gray box with no markings at all on it.

Thanks, bigjohn for your help on this.
 
  #9  
Old 02-06-03, 02:40 AM
bigjohn
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What about the gas orifice inside the pilot burner, did you take it out to see if it's clean?
 
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Old 02-06-03, 04:10 AM
AH30
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I have now and the reading is still 23mV
 
  #11  
Old 02-06-03, 05:08 AM
bigjohn
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The pilotstat safety control still won't stay pulled in? A cheap way to check it would be to go an appliance supply/parts place. You can buy a tester that is a replica of the pilot safety magnet switch. If the thermocuple will hold that closed but not your pilotstat safety switch, then replace the safety switch. Johnson Controls makes them [the safety switch that is, not sure who makes the tester], Part # L62AA-5C and Part # L62GB- 3C. Around $60 wholesale.
 
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Old 02-06-03, 07:01 AM
AH30
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Thanks bigjohn, I will try it. Fingers crossed!!
 
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