Cooling/Heat Problem

[furi0us]

We have a coleman 3400a816 serial number 088867338. when we turn on the t-stat and set it to 76 for cooling or heatin nothing comes one at all...the out side unit comes on but the blower inside the house dont come on. can you tell us what the problem might be? heres a picture of the wirrin for the transform and etc and let me know which one in the picture needs to be replace and how much it will cost thanks alot. it use to come on when u go inside and hit the lil black switch but it wont come on in auto.



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[Robert]

How many wires are connected at thermostat ?


Do you have fan switch at t-stat or do you have two switches on front of control box ?


Have you placed fan switch in the Continous ON position to see if blower comes on ?



Which black switch did you used to hit to get it to work



Thanks,
Robert

[furi0us]

only 2 wires its the type

u have to go inside of the unit to switch from heat to ac.

we have the one lil button black on ur left thas by itself. than we have a switch where u can turn it from heat to ac or off. and one lil switch beside the heat/ac/off is for the fan to put it in auto or manual.

well the black switch that is to the left by itself to turn the unit from auto to manual we use to turn that on manual and it use to come on but now it wont

and the fan unit outside for the ac wont come on unless u hold the button in on the reply switch but we replace that and it still the same problem.

could it be a transfor or sque?

[Robert]

The fan switch to the left by itself should be placed in auto and left there.


The two switches on front of a/c control box are what you use to change from heat to a/c and from auto to manual.


You should keep it in the auto position and only switch from heat to a/c when seasons change.


Set t-stat temp lever at temp desired.


Probably have a loose or disconnected wire or one of the switches or relays not allowing low voltage to pass through.


Would have to test for voltage by tracing the wiring diagram if knowledgeable in that.


Otherwise, will need to call an HVAC Tech to diagnose defective part or wiring problem.


Thanks,
Robert