Furnace power

Jim_22

This isn't steam/hydronic related, but I know someone here has an answer.
We experienced one hell of an ice storm here in the western NY area last Thursday night with approx 250,000 households losing power. I was out till Saturday afternoon, as of today there are still 20,000 people out.
I ran my house on a portable generator without problems, but when I tried the same thing at my In-laws, neither furnace in the double would run on the generator. Both are Goodman/Nordyne 100,000 btu, 92+, gas fired upflow residential furnaces. The generator was 120vac, 60 hz, 20 amps. On call for heat the draft inducer would spin up and prove, hot surface ignition would come on and the main burner would light, only to drop out instantly. Then the cycle would start all over again and again. In talking to people over the last few days I found others with high efficiency units who had identical problems.

I was able to run my computer while powering my house with this generator with no problems.

Any ideas?

Jim