Furnace doesn't heat

[Merici]

When I turn the thermostat up, air blows from my furnace, but it isn't warm air. The furnace doesn't seem to be "cooking" the air before it blows it out. I replaced the thermostat and the same thing happens. It's a gas furnace with electric ignition on the pilot. Any suggestions about what may be wrong here?

Thanks!

[kactuskid]

I bet if you turn off the power switch to the furnace and turn it back on, that it'll reset and start blowing warm air again. This just basically resets the problem, though it'll happen immediatly again. You should have a small light that's inside the panel on your furnace. Then number of "blinks" it has correlates to a problem. Your manual should tell you the code, it's probably a "lock out".

If it is, alot of things will cause this, a cracked ignitor or clogged flue are just a couple that come to mind. You'd be best to call in a tech to troubleshoot it for you since this is a safety interlock telling your furnace to shut down.

[Hube]

If the burner is lighting ok, the fan should not kick in until a minute or so after. This delay lets the heat exchanger get hot so when the fan does kick in it will be in the 130 degree range or slightly higher.
Question to you; does the air eventually get warm before the burner shuts off?
If the air always stays cool, then you may need to replace or adjust the fan's on/off control. It could also be a faulty fan relay.

[Merici]

Hub, no, the air never gets warm. I turned the thermostat up and left the house for a couple of hours. When I came home the house was no warmer. I know it should start heating first, then blowing the warm air out.

[Hube]

Merici; If on a call from the T stat the burner does'nt light,it could indicate a faulty gas valve, or an ignition problem(igniter)itself. Check it over for any loose contacts at the gas valve's terminals and also make sure the igniter is clean .(steel wool)
Have you checked to see if the burner lights up?
Have you checked to see if the igniter is sparking on start-up?
if your not familiar with these items, then your best to call in a Tech.