OK, a week ago my furnace blows cold air.. we call service man, he comes out and sais well you've got a bad gas valve! OK we better put a new one on since winter is on its way. He puts gas valve #1 on and it shorts out, he only had one on the truck so the next day he installs gas valve#2. alrighty man we got heat again, but wait why in the wide world of sports is the thing kicking on and off for?? It never did that before we put new gas valve on? The gas valve is a white rogers c6303 type 300. PLEASE SOMEONE HELP!! Any ideas?? :confused:

Your heat anticipator which is located on your thermostat has to set to the total amp draw of the heating circuit when he changed the valve the amp draw changed he should have set it then

If the new valve was the same part as the old one, I doubt it would have thrown the heat anticipator off that much. It sounds to me like you have a bad temperature sensor, or if an older furnace, a limit switch.