gas burner wont turn on

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  #1  
Old 03-07-08, 07:13 AM
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gas burner wont turn on

Help... I hear the circulator pump running but the gas burners wont turn on. I have a 2 zone hot water baseboard heating system in our townhouse. Here are pics of my heating system:
http://i213.photobucket.com/albums/c...er-outside.jpg
http://i213.photobucket.com/albums/c...ler-inside.jpg

My guess is the pilot light is out but I never saw a pilot light there in the first place. I have an electronic intermittent pilot ignition. The white object in the middle of the inside picture is the pilot light control. The entire system is 20 years old but I believe that the pilot ignition control was added over 5 years ago. Please send me any suggestions. I have johnson controls G779 Univ. Intermittent Pilot Ignition Control. My gas valve is a Honeywell VR844M. My boiler is a peerless cast iron boiler. I hear fast ticking or clicking for 5 times when the thermostat calls for heat.

Thanks for your help.
 

Last edited by vinny121; 03-07-08 at 08:01 AM. Reason: addd more tech info
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Old 03-07-08, 07:57 AM
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You have to determine if the gas valve is getting ~24 volts to the pv terminals on the gas valve, and if there is spark occuring down in by the pilot.

Not only do you need high voltage DC spark current coming out of the control module (AC voltage incoming to the module, high voltage DC transformer inside it), but you need a good ground for the spark down in by the pilot, and that is if nothing is wrong with the rubber insulated spark wire that might be allowing spark to bleed through the insulation to a metal ground before the ignitor.

Have you done any reading regarding all this on this forum as we have talked about this a lot here.
 
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Old 03-07-08, 08:45 AM
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hi, thanks for the reply

Do you have a link to posts that have this explanation? I did a search and it seems like there are other issues with different configurations. I am mostly interested and clueless about trying to troubleshoot live electrical circuits. I really don't know how to do that... I have a voltmeter and a voltage and ac current detector but thats it. How do I do that? Please help. If you have a more links, that would be appreciated also. I am a homeowner and usually don't do this too often.
 
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Old 03-07-08, 11:05 AM
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On the control module you should be able to rig up a screw driver or otherwise improvise to see if you can get spark to jump, at that point, between what you rest against the terminal (like a screwdriver metal), or connect to it, and a good metal ground. Hold it away say 1/4 inch. If no spark during any try for ignition we can then concentrate on the electrical end of things.

If you DO get spark, then we can find out either how it's not getting to proper ground in the burner, or if you have a problem with low voltage current geting to the gas valve.

Be careful that the module will zap like a car spark plug! So use the same care. And the test is basically the same as you'd do for testing spark at a plug.

And regarding the gas valve's PV terminals you should be able to set your voltmeter to an AC volt-range listed on your meter anywhere from 50-250 volt range and take a reading from a PV terminal to any good metal ground to see if during the try for ignition that ~ 24 volts shows up at the gas valve. IF it does, then retry the same test with the wire disconnected from the gas valve, and test the WIRE (with red probe on wire and black probe on any good metal, not the terminal, to rule out any possible backfeed.

If you do these two things, we can move on to further instruct.
 
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Old 03-07-08, 04:19 PM
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Exclamation Here is my test report... is it the control?

Hi,

Thanks for the informative test. The very first thing I did was test for 24V on the THS (thermostat) wire and that tested good. I also saw the green led stay steady. Then I tested for spark in the spark wire with a screw driver and that drew spark. But when I tested PV1 (gas valve) it did not show 24 V (just stayed at 0 Volts). According the control instruction manual, I looked up case: spark is present but pilot will not light. If this case fails, I need a new control. Is this true? By the way the plastic on the bottom right rear of the controller is all warped and cracked... don't know if that means anything. So am I right to say the control is bad? Please reply...its pretty cold in here. Either way the stores are probably closed now.

I wanted to see the pilot light so I tried to remove the boiler tube (1 in dia) but the pilot gas tube (1cm dia) was preventing me from doing that. Is there an easier way to see the pilot light? Because it is pretty concealed. I had all the lights off and I didnt see any light when the system was sparking. The pilot ignitor is behind some metal concealed in the boiler.

Anyway at least I now know how to remove and clean those long tubes now!
 

Last edited by vinny121; 03-08-08 at 01:12 PM. Reason: added more detail
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Old 03-08-08, 01:08 PM
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Yes, it sounds like it is the control module. The reason is that since you are getting spark at the module, this means you are getting the necessary 24 volts through the entire safety switches system as you should (ruling out a problem there), so therefore you are getting 24 volts coming INTO the module. And you are getting spark to leave the module. But for some reason, once the sparking starts, it is not completing the circuit inside the module that allows 24 volts to come out of it to go to the pilot connections at the gas valve. And the fact your module is warped and cracked pretty much clinches it.

Make sure no condensate water from say a leaky draft inducer gasket above has not been leaking down onto the module. You wouldn't want to put in a new module and have some leak start working on the new one.

Let us know if this fixes it for you.
 
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Old 03-08-08, 01:49 PM
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right again!

You are right. The pipe for the taco circulator pump is rusted (above the pump where it connects to the pipe). Of course everything vertically below it is rusted too. Plus the control module is located just below the leak. I guess I need a plumber to replace the gasket because some water is seeping through? I won't know where the water is coming from exactly until I run the system again with the new control. I have ordered the new control module and will pick it up in a couple of days. Thanks for your help once again!
 
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Old 03-12-08, 07:20 AM
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Hi the control module was replaced and the heat now is on! Thanks once again. I put insulation on the pipes to avoid this issue again. I purchased 1/2 inch thick insulation that had adhesive to close both ends. As soon as the heat turned on, the adhesive failed and the insulation separated. This is frustrating since I purchased the largest internal diameter (1 1/8") insulation that Home Depot had. Anyway, some insulation coverage of the pipes is better than none.
 
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