Hello, My name is XXXXXXX XXX I will do my best to help you today.

Is the indoor blower coming on it is just that the outdoor unit isn't?

if you turn the thermostat to fan "ON" does the indoor blower come on?

you have no power ot the Furnace. this could be a breaker, a loose high voltage wire, a loose thermostat wire, a blown fuse, or a blown transformer

Inside the furnace is a control board that may or may not have fuse protection depending on the model furnace. Check this fuse and see if it is blown looks just like a care fuse will be a 3 or 5 amp

Also check the breaker and the switch on the wall next to the furnace and make sure they are on.

on this board the fuse is plugged in to the top center of the board.

the blower is running?

or you mean it works only when set to heat?

on your thermostat where the wires hook up is there just an R terminal or is there an RH and an RC terminal?

you have to pull the front off

The red wire goes to a terminal marked R or RC or RH?

I only ask because the RTH2300 was made two different ways. One way they have an R terminal and then to the right of that terminal is a space where it looks like another terminal would be. On other older models they had an RH and then an RC in that empty space .

okay perfect

now is there a jumper wire hooking the RC and R terminals?

the red wire goes to R doesn't it? nothing is under RC?

You need to take a small piece of wire and make a horseshoe shape and install this into the RC and R terminals connecting them together to make one terminal so the red wire is energized by both of them. The thermostat came from the factory with this jumper but it has fallen out somewhere along the way or disregarded at installation of the thermostat.

If the red wire is only touching the R terminal only the heat will work. If the red wire is only touching the RC terminal then only the cooling and fan "on" will work

that is the jumper

So make sure that this jumper is intact and tightened down

right

so if the heat works the cooling should work.

is the red wire under the RC or the R?

http://customer.honeywell.com/techlit/pdf/PackedLit/69-2606ES.pdf is this what your thermostat's terminal strip looks like? page 6

http://customer.honeywell.com/techlit/pdf/PackedLit/69-2448ES.pdf or is it this one page 5

and if the red wire is under G then what is the green wire under?