2 wired t-stat

You need to preform a continuity check between your T-stat wires. More than likely, the wire that initializes the call for heat is grounded to one of the other wires. Also, if the unit worked fine prior to the initial problem, it's likely that you haven't purchased the proper t-stat for the unit. Wall heaters typically operate using a millivolt t-stat and not your typical heating stat you would find on a central unit. If you did purchase the correct stat, then more than likely it's not wired correctly, or you have a direct short, as mentioned above, in the wiring.

As usual.....when dealing with electrical, no matter how low of current, please turn off the gas and any electrical current that the unit may have prior to servicing.

It depends on which wires are crossed. Switching the wires on a two wire high limit, thermostat, or thermopile will not matter. The wiring on the gas valve must be correct for the fryer to work properly and safely.

More important than the length is the routing of the wires to reduce chances of cross-feeding of the ignition pulse into another wire.
Don't know if any place shows the routing of the plug wires.. You may need to look at another engine like yours to see how the wires are routed and which length wire goes where. Good luck.

IS your thermostat set to automatic on the fan switch? If so then you may have a stuck fan relay in the air handler. If it has an electronic control board the relay is on the board and the whole board would need replaced. If it is not a stuck relay then you could have a crossed wire from the thermostat to the air handle, usually the green wire from the t-stat, it could be crossed with the red wire that supplies 24 volts to the t-stat.

If the circuit breaker is not tripped (and you have line voltage to the unit) - and your inside blower motor is running - then your problem is with the thermostat/or the wiring from t-stat to outside unit.
Could it be you don't have the t-stat set on "cooling," or possibly not set at a low enough temperature to allow the unit to be turned on? Note: your t-stat must be set 'below' the inside temp, i.e. if the room temp is 78 degrees - you must turn the selector to below 78, i.e. 75, 74, so on.
Check your low voltage wire going to the outside unit - usually a thin brown wire which encases 2 smaller wires (usually red and yellow) that goes to the 'starter relay' inside the outside unit. Make sure a dog hasn't chewed it in - two - or someone hasn't cut it with a weed eater. If this is the case, turn the t-stat to off, and un-plug the inside unit (furnace) and splice the wires back together.
You can do this fairly easy with a pair of cutters and if the wires are 'color coded' you will know which wire(s) to splice back together. Note: this is 24V wiring but still you should make sure power is off - because 24V can zap you sometimes - AND you want the power off so you don't 'cross' the wires and short out the transformer.
There is a chance that the thermostat is bad - but it is not likely, and in any event you'd probably need a serviceperson to diagnose this.

Disregard wire colors. Instead wire by terminal designation. In other words :
Wire on "R" Terminal on old thermostat to "R" Terminal on new thermostat no matter the color.

T-stat wiring is commonly connected with the following color codes:

On a straight heat and cool system:
White = W on T-Stat
Yellow = Y on T-stat
Green = G on T-stat
Red = R on T-stat

On heat pump systems:
Blue = W2 on T-stat

There is no guarantee that your system is wired using this system so you will need to look in the furnace and see where the wires are connected to. You will have another set, probably 2 wires, going to your outside A/C unit. They are typically red and white but could be any color as long as they are hooked up to the same connections. I.E. blue on R at t-stat and to R on furnace would be OK, it just makes it harder to service the unit if you don't know what wire is for what.

Just check your furnace connections and connect the same wires to your t-stat no matter their colors.

It dose not matter what color the wires are, put 1 wire on the w terminal and the other on the r terminal, if you have a millivolt system check the instruction of the thermostat to see if can be used on a millivolt system, Good luck.

r stat to r furnace
w stat to w furnace
g stat to g furnace
y stat to y furnace to condensing one wire to y the other to netural of the trans former c it doesnt matter which colors as long as it is wired like I just said. good luck Tom

your red wire will go to the R, RC, or RH terminal on the stat does'nt matter which one ,this is the wire that provides 24 volt from the furnace. the white wire will connect to the W terminal on the stat. If there is a jumper wire that came on the stat going from RC to RH leave it on.