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Hello, its very difficult to verify the safety switches with a volt meter on these AC electronic systems because of feed backs (that is not a problem on DC circuits like in a car but is with these systems)
Please attach a well focused, close up photo of the wiring diagram glued inside the service panel, you can use the paper clip icon at the right end of the toolbar at the top of this dialog box, Include a picture of the thermostat wire connections to the printed circuit board in the same area.
If there is no paper clip icon, look for the '+attach files' link at left of your send button.
I can mark it up with trouble shooting instructions. You will need a multi meter ($30 at a hardware store) and some experience working with appliances, let me know a lot about your skill sets in those regards.
Try sending the pictures again, none arrived, use the paper ciip icon at the right end of the dialog box tool bar, or the '+attach files' button to the left of your send button do do that.
Or you can post them to www.flickr.com and post the URL for the pictures on flickr here.
We can go from there.
Our server has been known to be a bit buggy at times. I got 3 photo's this time. However they were all of the printed circuit board.
The wiring diagram is an 8 x 11 sheet of paper plus or minus a few inches, printed with the wiring diagram, and glued to the inside of the blower service door.
That photo must be very carefully taken with very good light, from straight on, not at an angle, and exceedingly well focused. That is the one I mark up with trouble shooting instructions...
I see the area is poor lit, you may want to take the panel with the diagram on it, into the house where the light is good and take a close up of it, there... again the photo must be taken from straight on, any angle will blur it out so that I cannot read the fine print on it.
Hello again, that type of igniter has on average a 2 to 5 year life span, it it has not been replaced in a long time there is a good chance its bad... during the ignition phase, check for voltage to the igniter, and if you have voltage there, usually 120 volts, but sometimes those are 24 volt igntiers. and the igniter is not glowing, it is a bad igniter... remove it, and if you see a black line across the face of the heating element it is bad for sure.
Beyond that, the way to text limit switches, is to bypass them with a jumper wire *briefly, for a test only... attempting to do it with a volt meter leaves you open to getting ghost reads.
Let me know how this goes.
Thanks, I still need you to check voltage to the igniter... there is a mosaic of interactions here that I am considering... one test tells me a lot about a range of problems in the system.... ohm tests are also good, in my 51 years with the tools however, about 90% of my ohm reads were bogus, I had to take them repeatedly to insure the test probes were making good contact in order to get good reads.
Did you test the limits with a volt or ohm meter or by jumpering them... Jumpers are all that work 100% reliably, due to electronic feed back in the AC circuits.
The ventor motor is required to come on *before* the ignition will be powered... you have that sequence of operations backwards in your mind. That is the root of some of your confusions.
The other aspect is that you are relying on meters (sound assisted or not) to provide accurate readings, when in fact they very often provide false reading.
Operating on the basis is going to lead you off into the tall weeds. I don't know how better to say it.
I will opt out now so that other of our experts here can take a look and decide if they can help you on this range of issues and problem with your furnace. Good luck with all.
Good Afternoon, I am Kevin, one of the techs here.......
I read over what you and Phil did. Can I ask what symptoms you had before you changed the board?
So if I understand you correctly, you had exactly the same symptoms before you changed the board?
have you tried at the board, jumping R and W?