Help -- A/c And Heat Out !

[arsenalfan]

I have a 2 story home, upstairs has a goodman unit that powers both AC and Heat, and downstairs I have the Goodman unit that powers the AC and then the gas furnace to power heat. All of a sudden yesterday the whole downstairs seemed to just shutdown. By that I mean no heat, no air, no fan, nothing.. I thought I'd be proactive and go and buy a new thermostat ( I was looking to upgrade anyway).. Then like a dummy I took the old thermo off tghe wall and did not label where the wires went to, so, I attached them to the new thermo by color.. Its a 4 wire system with yellow, red, white and green..I put in ther new thermo, and NOTHING.. still no power... I checked the breakers in the garage and they were fine... The unit upstairs works just fine for both heat and air, so I'm kind of confused... I was going to call someone out but really, if I can save a call out charge, I would like to...

as you can tell I;m no expert so any help would be appreciated..


** update ***

I did some tests after browsing online and there is no power to my thermostat.. I tried shorting the ac, the fan and the heat and no response... so does this mean a visit from the HVAC guy or is there something I can do myself ??

[mud]

first thing i would do is make sure the blower door is on completely. There should be a switch the door pushes against. If your not familiar just be careful of line voltage in that area or kill power.

[HayZee518]

control power is most likely 24 volts. fan high limit switches are 120 volt. the door switch someone mentioned is probably 120 volts. look inside the unit's control section and see if you have 120 to the transformer primary, if you do measure the secondary should jave 24 volts. check to see if you have a control circuit fuse. a glass SAE type fuse may be the problem. the gas control is part of the burner lockout so this won't even enter into the equation. there may be some over heat thermal switches in the circuit but these are automatic reset. the are normally closed devices.