We have just turned the heat on for the season. Our upstairs heat is working fine, but there is no heat downstairs even though the thermostat says the heat is on. The fan works when turned on but only blows cold air.

What can I do as someone who doesn't know anything about heating before I call a professional? I have already checked to make sure the main breaker isn't flipped.

What type of heat do you have for your downstairs? See here for other things to add about your system to help get a good answer. So you have separate heating systems for down and up?

* Detailed explanation of all symptoms - Be as brief and specific.

The downstairs thermostat says the heat is on though nothing is coming from the vents. The fan does work when it is on (only blowing cold air). When I turn the thermostat to on, I can hear something running at the intake vent. I haven't been up to check if anything is running in the attic though because I am home alone with two small children.

* What type of heating system, such as:hot water baseboard, forced hot air, etc.

It is a central heating unit. Carrier is the maker. It heats both floors with separate controls on each level. My upstairs heat works fine. I did go in the attic and made sure a switch wasn't flipped, but I don't know what else to check for up there.

* What type of heat source, such as oil, natural gas, electric, etc.

Heat source is natural gas.

* Make and/or model number of the heating or cooling unit, themostat, zone valve, etc.

I don't know the make or model number, and I can't get into the attic to check before my husband comes home late tonight.

I did call someone to come, and they will be here tomorrow. I just wondered if there was something I overlooked. I'd hate to pay oodles of money for something that is simple to fix.

Thanks for any help.

I can answer my own question now. It was a bad gas intake valve. Part was under warranty. Do these things usually go bad after just 2 years?

Not usually but with any thing man made they can. I'm a tech and have seen them fail in days.