Amana/Goodman furnace odd issue

[Robert Adams]

Ok got it up and running... When it comes to something failing for me it is always the " I have never heard of that failing like that before" or the " that shouldn't cause that". For me and everything I work on weather it be cars houses machines you name it. For me it will always be the most obscure failure mode known to man that not even the engineers have even thought about it... 

           I went over what it was telling me in the code.. Now I have learned to distrust the usual testing and methodology as for me it rarely works... Got to thinking about the neutral to ground and hot to ground. Now the meter said it was good but... I say don't trust it cause I know better... 
           

            So I figure let me bond the neutral and ground at the unit and see what happens. Lo and behold all is good again and working perfect as soon as I connected them. So I undo that and go to the panel and move the ground to another hole same with the neutral and get them nice and tight again and then pull the bonding screw and clean it a little and crank that screw back into place. 

        Now we are all good. The meter was showing it as just fine but for some reason the board is extremely finneky and sensing something my meter couldn't.  


            Now I can tall you about the 94 Le Sabre I bought as a dealer buyback since they couldn't fix it. Had 20K on it and I paid 3K for it. Check engine light would come on as soon as you started the car for the coolant temp. They tried everything except... 
           Through my experience with those ecms at the time... I turn the key on let it sit for a few seconds before trying to start it. Crank it and no light and all is good. The ECM was bad and they kept preaching it's never the ECM it's wiring etc. I was letting the ECM warm up. 
            I put a $100 ECM in it drove for another 140K with minor repairs and would top out at 36mpg on the freeway...

[Phil Thien]

            Now I can tall you about the 94 Le Sabre I bought as a dealer buyback since they couldn't fix it. Had 20K on it and I paid 3K for it. Check engine light would come on as soon as you started the car for the coolant temp. They tried everything except... 
           Through my experience with those ecms at the time... I turn the key on let it sit for a few seconds before trying to start it. Crank it and no light and all is good. The ECM was bad and they kept preaching it's never the ECM it's wiring etc. I was letting the ECM warm up. 
            I put a $100 ECM in it drove for another 140K with minor repairs and would top out at 36mpg on the freeway...

But did the Le Sabre's heater work?

[Robert Adams]

But did the Le Sabre's heater work?

       It actually did... The AC was freezing cold which was more important in Texas. The El Camino on the other hand is always cold even though it has the same HVAC as a station wagon for just a 2 seat cab..

[Roly]

       It actually did... The AC was freezing cold which was more important in Texas. The El Camino on the other hand is always cold even though it has the same HVAC as a station wagon for just a 2 seat cab..

I think when you pulled the bonding screw and cleaned it that is what was the real fix,  I would think if you returned the ground wire to the ground bus it would continue to work.   A digital meter can give misleading readings as they put a very small load on the circuit.  Remembered it worked for 6 years as it was.   Roly

[Robert Adams]

I think when you pulled the bonding screw and cleaned it that is what was the real fix,  I would think if you returned the ground wire to the ground bus it would continue to work.   A digital meter can give misleading readings as they put a very small load on the circuit.  Remembered it worked for 6 years as it was.   Roly

             It's all back to the way it should be. Yeah I still use my old wavetek meter and it doesn't have the features of the newer meters. They were bought by fluke and they changed the colors etc and kept selling them as fluke meters till they phased out the older ones.

           And the panel is only about 10 years old as well but for some reason one device had an issue with it having invisible oxidation..

[blackhat]

More surprising is that you weren’t getting flame sense faults with a bad ground. Glad you found it.

[Robert Adams]

More surprising is that you weren’t getting flame sense faults with a bad ground. Glad you found it.

        Not so much a bad ground but what the board is doing is at every power on and every cycle start when it lights the ignitor it checks to see of the panel is bonded. The tiny millivolt signal it was sending through wasn't making it through the connection. So hot tip if you are trying to power one up in an old house that isn't grounded you will have to bond at the unit. Same goes if you are trying to temporarily run a unit on a jobsite etc. 
 
     It's the only device I have run into that actually checks and will not run on an unbonded panel (or one with a hare of corrosion on the connection you can't see).