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tonyguy · Mar 8, 2009, 05:30 PM

Hello I have a carrier 1990 central gas heater not a heat pump the other day I turned it on and nothing I went into the garage and heard the ignitor clicking and could hear gas coming out of the pilot but no flame I measured the volts coming out of the ignitor box and it was 10 volts I then turned the system on and put a lighter at the pilot don't worry I had the lighter on first The pilot lit up and after about a minute the furnace came on then when it warmen the blower came on and my house heated just fine when I shut the system down all worked great the flame went out the blower stayed on then shut down here is the model number 518cxx036ooomaaa I am thinking it might be the ignitor or the control board ps the ignitor doesn't sound as loud wheb clicking as before anyhelp would be great ty Tony:cool:

hvac1000 · Mar 8, 2009, 10:44 PM

Does you pilot assembly have 3 wires like this? If so try cleaning the pilot orifice to see if that helps. If the unit is clicking as you say then that noise is probably the spark jumping or near the pilot spark assembly. It could also be a defective high voltage wire that carries the spark voltage from the board/ignitor control to the pilot spark assembly. You might also look at this in the dark when sparking to see if the voltage is jumping to a place where it does not belong proving a bad cable.

tonyguy · Mar 9, 2009, 02:01 PM

Originally Posted by hvac1000

Does you pilot assembly have 3 wires like this? If so try cleaning the pilot orifice to see if that helps. if the unit is clicking as you say then that noise is probably the spark jumping or near the pilot spark assembly. It could also be a defective high voltage wire that carries the spark voltage from the board/ignitor control to the pilot spark assembly. You might also look at this in the dark when sparking to see if the voltage is jumping to a place where it does not belong proving a bad cable.

Do you think it can be a defective ignitor box ? The clicking is very quiet before it made much more sound also I pulled the red wire and touched the ignitor box while it was clicking and no sensation of electrical impulse thanks for any help PS haven't cleaned anything yet .

hvac1000 · Mar 9, 2009, 02:07 PM

I pulled the red wire and touched the ignitor box

Take red wire to a ground and see if it produces sparks during the ignition cycle
The red wire should be spaced 1/8th inch or so from the ground to see if the spark will jump.

tonyguy · Mar 9, 2009, 03:36 PM

Originally Posted by hvac1000

I pulled the the red wire and touched the ignitor box

Take red wire to a ground and see if it produces sparks during the ignition cycle
The red wire should be spaced 1/8th inch or so from the ground to see if the spark will jump.

I did that and nothing I also put a new wire from the ignitor box to ground 1/8 inch away and no spark it sounds really weak

hvac1000 · Mar 9, 2009, 05:21 PM

Sounds like a defective high voltage power supply.

tonyguy · Mar 9, 2009, 06:01 PM

Originally Posted by hvac1000

Sounds like a defective high voltage power supply.

Would it be in the black ignitor box or the control panel ?

hvac1000 · Mar 9, 2009, 09:42 PM

Black ignitor box would be my first suspected component. I would replace it after it was tested and found to be defective.

tonyguy · Mar 10, 2009, 12:55 PM

Originally Posted by hvac1000

black ignitor box would be my first suspected component. I would replace it after it was tested and found to be defective.

Thanks for the reply can I test it myself ? If so how ? And like I mentioned earlier the volts going into the black ignitor box was 40 from the control panel board the volts coming out were only 10 thank you for help .

hvac1000 · Mar 10, 2009, 02:02 PM

Usually the voltage for the black ignitor in is 24 volts range on the imput side. Usually if the box generates a spark it is good but if not it is bad.

tonyguy · Mar 10, 2009, 02:12 PM

Originally Posted by hvac1000

usually the voltage for the black ignitor in is 24 volts range on the imput side. Usually if the box generates a spark it is good but if not it is bad.

Coming out of the ignitor to the pilot is only 10 volts

hvac1000 · Mar 10, 2009, 04:35 PM

Actually it should be a lot more than that.

Does it look like this one.

hvac1000 · Mar 10, 2009, 04:49 PM

If you have 24 volts on the supply side of the spark box but only 10 volts from the high voltage stud to ground then I would say the spark box is bad.

http://cgi.ebay.com/Carrier-Spark-Ig...QQcmdZViewItem

tonyguy · Mar 10, 2009, 05:20 PM

Originally Posted by hvac1000

Actually it should be a lot more than that.

Does it look like this one.

Yes exactly

tonyguy · Mar 11, 2009, 11:29 AM

Originally Posted by tonyguy

yes exactly

Yes that's the one how many volts should be going into it ? From the T 1 & T2 ? I called a Heating guy and all he wanted was my money he said its not that there are many things it can be and said he needs to come over I said no thanks

hvac1000 · Mar 11, 2009, 01:57 PM

The spark box uses 24 volts as its power source. Look on the inside of the blower door for your wiring diagram since I do not have one.