[ScottJamie]

Coleman EVCON furnace/central air forced heat/air? Is what's on the furnace inside the pantry.

The air worked fine this morning, then as soon as my husband left, I realized I was warm, and checked the thermostat. It was 85 degrees in the house (but was set on 72) and the unit wasn't working.

When my husband came home, he flipped all switchs on the inside unit, and the breaker (although they had not been tripped). The unit will not come on, nor will the Auto Fan come on.

Could this be a thermostat problem, or something with the central air/furnace. Any helpful tips, or advice is welcome.
Thanks in advance!
Jamie

[labman]

Easy things first. There is a single pole breaker for the furnace, not the 2 linked together for the air. Throw both of them as far as they will go toward off, and then back on. If that doesn't do it, it may be the controls.

Usually there is a 24 volt AC transformer in the furnace with the secondary winding connected to a red wire running to the thermostat and a blue wire, common, to the gas valve, A/C relay, and fan relay. From the thermostat there will be white wire to the gas valve, yellow to the A/C, and green to the fan. The thermostat is wired to switch the power from the red to the white, yellow, and green as needed with the blue completing the circuit. Most thermostats and furnaces have the contacts labeled R, B or C, W, Y, and G for the corresponding wire colors. It may be wired to have the A/C control wires return to the furnace and its controls and then a second wire goes to the A/C unit. Internal wiring may replace the green wire if the thermostat does not give you the option of fan only or continuous fan. Digital or programmable thermostats may need the blue wire connected to them.

With the thermostat set to cool, check for 24 volts between the Y contact and the B or C. If not, check the R and B for 24 volts. Often there is a small fuse before or after the transformer. It you have power to the Y terminal, chances are either the blower of compressor would work.