Heater won't turn off!!

[tnickers]

We have central heat / ac & the heater isn't shutting off at the temp the thermostat is set to...this morning I had to shut off the breaker, but as soon as I turned it back on tonight the heater started up again (therm was OFF). I turned the therm on & set for 71, but the heater stayed on and temp is now 72. Anyone had this problem? I know the whole unit is old & we need a new handler, but could this be something else? Hubby won't be home for another day or so (trucker) & I'm hoping someone here will know what I'm talking about. Thanks!

[HayZee518]

if the thermostat didn't have any effect then I would turn to the control circuits of the unit. a relay could be burnt closed. these are litte relays about the size of a half pack of cigarettes. control circuit is probably 24 volts.