gas furnace not firing up
We just replaced our older heating system with a new Trane dual-fuel system. Everything has been fine, but we have a problem now. With the thermostat on Auto system, we understand that the heat pump will work until it can't, and then it will call up the gas heater. But sometimes the gas heater doesn't want to engage. We can hear it trying to fire, and there is an interesting yellow glow that we can see in the heater (looking through the grill work). But it doesn't always fire up, and last night the furnace tried for a good five minutes before the decision was made to manually change the thermostat to Emer. heat. When that was done, the heater fired up just fine, and cycled off and on during the night to keep the house temp. where we wanted it. We have had the technician out, and he has checked the system and declared that everything is set okay. An interesting note: our older system, which was not a dual fuel system, but just a gas heater plus an AC, had the same problem toward the end of its time with us. Could we have a gas pressure problem, instead of a heater or thermostat issue? Many thanks for any ideas.