View Full Version : Bad control board
Blue Hen Mom
Feb 21, 2009, 01:38 PM
We have an older Trane gas furnace (TUC series) and the control board went bad (model 50e47-060). The furnace would come on, but there was no signal to the ignitor per the technician who wanted to charge almost $1K to replace the control board. With money being so tight, we purchased a new board on our own, part #cnt03776, model 50e47-860, and installed it per the instructions. The furnace worked for about a day, but we are evidently having the same problem. The furnace kicks on, you can hear it preheating, and you can hear the click to send the signal to the ignitor but nothing. The light on the board is solid green, indicating normal function. Does anyone have any ideas about what we should look at next to get some heat? And is it possible that we may have shorted out the new board? Thanks in advance for your help!
KC13
Feb 21, 2009, 02:45 PM
Have you checked the ignitor? These fail more frequently than ignition modules. Look for a crack or pit near the center of the element. Handle with the same care you would an egg, and don't touch the element with your bare hands.
Blue Hen Mom
Feb 21, 2009, 03:06 PM
Have you checked the ignitor? These fail more frequently than ignition modules. Look for a crack or pit near the center of the element. Handle with the same care you would an egg, and don't touch the element with your bare hands.
The technician did say it looked pretty rough and would probably need replacing soon. Thank you for your input... I'll definitely check that out.
mygirlsdad77
Feb 21, 2009, 04:16 PM
After you hear the click signaling the glow plug to come on, do you hear another click shortly after(say ten to thirty seconds later) that turns the gas valve on(you should be able to hear the flow of gas if this is happening). If so(and glow plug never glows, then I'm betting you need a knew glow plug(igniter). If you or somebody you know is handy with a multimeter, you could test wires going to glow plug to see if you are getting 120v when glow plug should be glowing. If you get 120, then definitely a bad plug. If no voltage, then the problem lies elsewere. Please let us know what you find.
Blue Hen Mom
Feb 22, 2009, 06:41 PM
Well, we got the ignitor out... and the wire has been spliced to add about another inch to the lead wires. Now I'm concerned that the replacement part # on the ignitor's connector, B144676P01 is not correct. It also has another number, Norton 271N on it. Is it normal to splice wires on an ignitor?
mygirlsdad77
Feb 22, 2009, 06:59 PM
Yes, you can splice the wires(as long as igniter is same voltage,usually 120v.) There are many universal igniters out there that requir splicing of the wires. As long as the igniter mounts correctly and is located exactly the same as the old one, you will be fine splicing the wires. Just make sure that all braiding around wire is intact outside of splice.
Here is what I recommend for splicing. Don't cut the connector off the control side. Cut the connector off the old glow plug and the new glow plug.(leave enough wire for splicing). Now splice the connecter from the original plug to the new plug, this way you will be able to use the quick connect on the furnace. Also in the future if you need to change the igniter, you will still have the quick connecter at the furnace. Let me know if this is making sense. And please let me know if the glow plug fixes your problem.
KC13
Feb 22, 2009, 07:26 PM
With the ignitor out, look closely at the surface of the heating element. Any cracks and/or pits, particularly near the center? If so, replace it. Try to find an OEM replacement if at all possible.
Blue Hen Mom
Feb 26, 2009, 08:33 AM
Well, thank you for your input. We got a new ignitor, installed it, and we now have heat! Not sure what you mean by an OEM ignitor, but we purchased the same make and model that was in the unit (looks like a long M with a flint-ish surface). All in all, this was a HUGE learning experience for us. And the cost to repair it on our own was much less than the vendor, $350 versus $1030. Thank you all again for taking the time to answer my questions!
KC13
Feb 26, 2009, 09:27 AM
Don't sweat that vendor - they will find a replacement victim soon enough... :rolleyes:
mygirlsdad77
Feb 26, 2009, 05:56 PM
Glad you got it fixed by yourself. Good job.
Blue Hen Mom
Apr 5, 2009, 05:21 AM
Hi... I'm back... heater's not working again. First, we replaced the control board as indicated above, then we replaced the glow stick. Now, the new board indicates a lockout. I've reset the system twice. You can hear the cycling series but again the blower is not coming on. My husband says he checked and there is power getting to the igniter. Any ideas?
wmproop
Apr 5, 2009, 05:45 AM
Have you checked ? Is there power going to the blower?
This is a big problem with Trane equipment,, we label them along with Lennix as junk
If its old as you say, it might be time to think about upgrading to a new and more fuel saving furnace,, when they get old they will dollar you to death
Goodluck
Angrycustomer
Jul 13, 2010, 09:08 AM
Well, thank you for your input. We got a new ignitor, installed it, and we now have heat!! Not sure what you mean by an OEM ignitor, but we purchased the same make and model that was in the unit (looks like a long M with a flint-ish surface). All in all, this was a HUGE learning experience for us. And the cost to repair it on our own was much less than the vendor, $350 versus $1030. Thank you all again for taking the time to answer my questions!
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I think the ignitor could have been replaced for about 120 bucks in say 60 minutes if I was there. Did you buy a spare ignitor too? For 150 bucks I would have offered you a full fix and a spare ignitor... at least you have the board replaced. I would send it back if you can... then your repair will be closer to the cost of a technician's rate but the time involved is still much of a nuisance. Those ignitors get calcified from the flame. You can't clean them. Its not the best ignition but easy to replace! I check them with resistance not voltage. Once they get dirty or a hairline or pit they start to read differently. Voltage of course gives you the tell tail sign of off or on; however, you can measure the resistance to see how soon you will need a new one...
Angrycustomer
Jul 13, 2010, 09:18 AM
Hi.....I'm back....heater's not working again. First, we replaced the control board as indicated above, then we replaced the glow stick. Now, the new board indicates a lockout. I've reset the system twice. You can hear the cycling series but again the blower is not coming on. My husband says he checked and there is power getting to the igniter. Any ideas?
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moisture in the pressure switch is a common failure... and easily rectified. Take off the 1/4" tube from the inducer motor from the switch and suck on it honey. If it clicks and the flame comes on your problem is moisture.