Generator question

[evanc]

So after 11 days in the dark and cold and reports of 10more days I need some advice. My forced hot air gas furnace is relatively new and has a computer board in it. I have been warned not to hook my old job site generator to the furnace for fear of damaging the computer. The generator has plenty of wattage to do the job.

Are these concerns valid? If so what do I need to do to run my furnace off this generator?

Would a good sized inverter...car battery....charger....generator be ok? If so how big an inverter do I need?

Sorry for so many questions, but I know for this kind of advice this is the place to be.
Thanks from the jersey shore...Evan

[Osvaldo de Banfield]

I think that no problem would be if the generator has power and voltage corresponding to the oven you are wanting to wire to it. Computer must be SMPS or transformer isolated from the supply, so if it has a rare waveform (not too sine), the CPU will never know it.

Are you damaged from Sandy?? Lament if it is true!

Salu2.

[kevinahcc20]

Check the furnace before you hook up to determine how the control module is wired. Chances are that the control module is powered off a DC supply fed by the 120VAC mains to the furnace. If so I would expect the DC supply to provide any needed isolation from noise, etc on the mains supply. If I had been in the cold for 11 days I'd likely be taking the chance.

[Frank Berry]

The generator should run your furnace just fine.

[evanc]

Thanks for the replies. We have a wood stove in the living room that is now also the bedroom for the 4 of us. The temps are mid 50s f overnight. Not too bad, at least I have a house to heat. If the furnace worked I could get out longer without worrying about the house getting cold during the day and not being able to warm it up before nightfall. Also I believe it would give my wife an emotional lift to hear the furnace fire up.
Thanks, Evan

[Enzo]

Be careful, make sure to isolate the furnace connections from the rest of the house wiring, otherwise the generator will try to power the whole house back through the service panel. And if the power grid outside should come back online wwhile you are generating, something will blow.

[freax]

I've been researching this a little bit, and I've picked up the advice from someone else that putting a 60w-100w incandescent or halogen light load onto the generator wired in parallel to your furnace will give the generator a steady load, and won't result in the generator stomping on its choke or throttling up to compensate for a heavier load.

But this is all relative to the load that the furnace is going to put onto your generator, and the size of your generator, can we get some further information about your setup there?

You say the generator has plenty of wattage to do the job, how much is it?

Whats the wattage of your furnace fan?

You mention an inverter, NO! if its a modified sine wave inverter then NO don't use it!!, if its an extremely expensive $1000 pure sinewave inverter then yes it might work, but be very careful of manufacturers stating that an inverter is a pure sinewave when infact its not! If it says "pure" on the inverter then thats not a good sign!

If the furnace has a mains powered fan in it then this WILL burn out when run from a modified sinewave inverter...

[tvrgeek]

A nice big line filter would not hurt.

[evanc]

The generator is 8k watt running and 13k startup. I knew to disconnect from the panel for the line mans safety. I tried it and the furnace doesn't work powered from his generator. The computer controlling the furnace has 2 LEDs that can flash diagnostic codes. I get a code that is not listed on the little chart in the furnace. Worth a try, but I couldn't make it work.
Evan

[tvrgeek]

Mine works fine. Processor controlled Carrier 89% type.

Do you ground your generator chassis? Actually required by code.