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  1. #1

    furnace and generator

    Ok, this one has me baffled. I have owned a Honda Eu2000I generator for a few years now. I have used this generator for camping and as a back up for around the house too. During the winter when we have power failures I've always been able to run our old (gas)furnace, fridge and a couple lights with no problems. Last year we upgraded our furnace to a new Trane high efficiency model. It has an electronic ignition and a computer control board in it. Well I just learned today (during a 4 hour blackout) that our new furnace wont ignite when plugged into the generator. The vent motor kicks on, then igniter tries to light but doesn't. Then vent blower turns off. Then the main blower turns on and blows cold air. The furnace shows an error code and that says "check igniter" During all of this the generator shows no signs of a large load.

    Things that I researched and have tried with no success...

    I changed the polarity...still faulted

    I bought and installed an eight foot ground rod with 6 gauge copper ground wire into the ground and connected it to the generator....still faulted

    I connected a ground from the house wiring directly into the furnace while plugged into the generator...still faulted

    But as soon as I plug it into the house current (after power is restored) she works like a champ!!! Generator....no go!!

    I just don't understand why when its plugged into the generator it wont ignite, but plugged into the wall its just fine. Other replies that i have read online is dirty power or uneven voltage. Well their fix for that was to use a nice inverter style generator like the Hondas or yamahas, but that is exactly what I'm using. I'm pretty bummed that we have no more back up for our winter power outages which unfortunately happen often in our area. If anyone with any experience with this that might have any ideas that I'm not getting, I would greatly appreciate your input.

    Rob

  2. #2
    Join Date
    Mar 2008
    Location
    Shelby Twp MI
    Posts
    820
    Do you have a kit for the house to plug the gen into or do you run cords? If you run a cord what gauge and how long of a run is it? Was there anything else hooked to the gen?
    Jim

  3. #3
    Join Date
    Nov 2004
    Posts
    1,024
    well this is on the border of DIY
    but here goes
    I will be general about why u can't get it to work.

    most generators give out a slightly different sine wave than what comes from the power co.
    this is why your furnace won't run.

  4. #4
    Join Date
    Mar 2004
    Location
    Grottoes VA
    Posts
    5,856
    Use a U.P.S. as a go between.
    Karst means cave. So, I search for caves.

  5. #5
    Join Date
    Oct 2001
    Posts
    6,855
    i'll take a shot....the TR in the furnace is it seeing a true 24Vs or higher sounds like it is trying to start and the VA pull is failing it.check it with a meter right on the TR on the secondary next time....you'll figure it out,have to have that furnace going during a winter power failure.try googling it their are a load of people trying to figure out why ...i put in 'generator running furnaces with electronics" they are saying it might be a truer ground furnace to generator,and generator to pipe.....and or the sign waves from the generator aren't what the power company supply
    "when in doubt...jump it out" http://www.youtube.com/watch?v=Px5YcOeQB4I

  6. #6
    Join Date
    May 2004
    Location
    Austin, TX
    Posts
    1,732
    Your sine wave is dirty, and the electronics do not like it.

    Buy a ac filter that has a couple of large capicators (sp) to smooth out
    the ac.

    This should solve the problem.

  7. #7
    Ok, I got it running off the generator!!! The problem appears to have been that the Honda generator does not have a bonded neutral ground like you find in normal house wiring, its a floating neutral. I guess the new Trane furnaces electric ignition system needs this bonded neutral ground to operate! I made an extension cord with junction box with a plug. In the box I jumped the ground to the neutral. I connected the ground from the ground rod outside to the generator ground terminal. I plugged in the new furnace and she is running great off the generator!! We now have our heat back-up for power outages again!!! Thanks again everyone for your replies!!!

    Rob

  8. #8
    Join Date
    Jun 2006
    Location
    SW MO.
    Posts
    5,060
    Last year I ran my furnace off my 5000 watt Troy-bilt generator. Had no issues. My furnace is a Trane XR80 mod. TDD100C945F3 ser. 40446KK1G with a W.R. Intel Ignition board p/n 50A65-476-07. My furnace has a cord so I was able to plug it right in to the generator.

    Just one word of caution, I put the generator right at the garage door with it fully open. The generator was venting towards the outside. My furnace is in the gararge. 5am the CO detector went crazy. I of course moved it farther outside and closed the garage door.
    I repair air conditioners to keep people cool when it's 110+ degrees outside.
    I repair heaters so people don't freeze to death.
    I shut down furnaces that are unsafe to operate.
    Make fun of my profession, but dang it, I save lives.

    We're awl pawthetic and kweepy and can't get giwrls. That's why we fight wobots.

  9. #9
    Join Date
    Mar 2008
    Location
    Houston, Texas
    Posts
    352
    Quote Originally Posted by edward301 View Post
    Your sine wave is dirty, and the electronics do not like it.

    Buy a ac filter that has a couple of large capicators (sp) to smooth out
    the ac.

    This should solve the problem.
    Very good advice, almost all of the portable generators put out sloppy power. This frequently causes electronics to freak and shutdown or constantly restart. However the natural gas generators that I've dealt with supply very clean power. (usually better than from the utility company)

  10. #10
    Join Date
    May 2008
    Location
    Jax Fl.
    Posts
    1,943
    A lot of the Hondas have a built in inverter that produces a "designer sine wave". They are actually good for electronics, if grounded properly.
    Just be careful of acidentally feeding shore power back into the inverter, since a failed one costs as much as the generator.

  11. #11
    Join Date
    Dec 2007
    Location
    Frognot TX
    Posts
    836
    I've used many generators over the years and never had any problems with the operation of any electronic devices, the first one I had was a 6 kw homelite with a 10 horse Brigs rope start, ran everything fine then got a Miller Bobcat that has a 10 kw everything ran great, now have a 54 kw that I pull with the tractor works good too. And I can run the whole place, no power shedding around here.

    I guess it's in the quality of the generator, the sine wave of 60hz electricity is 2200 miles long give or take, so it would have mess up fast before it got in your house

  12. #12
    Join Date
    Nov 2001
    Location
    east kansas
    Posts
    8,012
    Quote Originally Posted by z-family View Post
    Ok, I got it running off the generator!!! The problem appears to have been that the Honda generator does not have a bonded neutral ground like you find in normal house wiring, its a floating neutral. I guess the new Trane furnaces electric ignition system needs this bonded neutral ground to operate! I made an extension cord with junction box with a plug. In the box I jumped the ground to the neutral. I connected the ground from the ground rod outside to the generator ground terminal. I plugged in the new furnace and she is running great off the generator!! We now have our heat back-up for power outages again!!! Thanks again everyone for your replies!!!

    Rob
    The electricians may have a problem with the way your neutrals and grounds are ran. Try an electrical board to be safe.
    Beware of advice given by some guy on the Internet.

  13. #13
    Join Date
    Jan 2005
    Location
    Area 51
    Posts
    984
    Try keeping a 100 watt light bulb powered rom the generator all the time
    "Paddle faster, I hear banjo music"

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