How to troubleshoot this ac?

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Is there any way to know which of the secondary voltage wires from the old transformer (red or brown) is the Common "C" wire, and which is the "R" wire?

The new transformer does not come with wires attached, but labels terminals "R" and "C."

If there's any clue, the two terminals on the circuit panel they were connected to are labeled "C" and "T" but I don't want to assume anything and guess wrong. The brown was connected to the "C" and the red to "T."

Yes, energize the primaries on the transformer and then use a volt meter from one secondary wire to ground. If no voltage then that is the common wire.
 
What is going on here? I needed 18 gauge wire for the 24V transformer wires. I bought 18-2 wire, sold as "thermostat wire" and cut off the sheathing. The 18 gauge wires that were inside (red in the picture) are WAY smaller than the 18 gauge wires that I see elsewhere. The red and white thermostat wire fit in the 22 gauge space in my wire cutters.

If your saying the wire size is different AFTER stripping the insulation then one or more of the wires are not the size they claim to be.
Also, you can reduce the wire guage slightly with wire strippers, especially with solid core but, should be that noticeable when stripped using the correct slot on the strippers.
 
If your saying the wire size is different AFTER stripping the insulation then one or more of the wires are not the size they claim to be.
Also, you can reduce the wire guage slightly with wire strippers, especially with solid core but, should be that noticeable when stripped using the correct slot on the strippers.

Well Home Depot better give me my 40 cents back or I'm gonna raise hell.
 
For the secondary voltage wires, one end must be screwed to a terminal on the transformer, the other must be connected to a female disconnect. I must use solid wire because stranded won't screw well onto the transformer screws. Therefore, I must solder the other end to the female disconnect.

How can I do this when the disconnect is wrapped in plastic?
 

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Once again, I buy "18"-2 thermostat wire, this time from Ace Hardware, and it is not 18 gauge.
 
I hooked all,this up,today,and it worked fine.

I put the motor on "low" because that's what the old one was on. Is that okay?

This is the new motor, new transformer, new capacitor.
 

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I hooked all,this up,today,and it worked fine.

I put the motor on "low" because that's what the old one was on. Is that okay?

This is the new motor, new transformer, new capacitor.

I would expect the circuit board to have multiple speed terminal (low, med & hi).
the control board will select the speed based one mode setting (fan, heat, cool).
 
I would expect the circuit board to have multiple speed terminal (low, med & hi).
the control board will select the speed based one mode setting (fan, heat, cool).

The old motor had low speed connected and high speed capped with a wire nut. I just copied how it was.
 
The old motor had low speed connected and high speed capped with a wire nut. I just copied how it was.

I understand but, what you copied was incorrect. You'll stand a chance of freezing up the coils if you run it at low speed.
 
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I understand but, what you copied was incorrect. You'll stand a chance of freezing up the coils if you run it at low speed.

So which should I connect to that terminal on the circuit board? Or should more than one of the speeds be connected? If that is the case, I don't know where to connect any of the additional wires.
 
So which should I connect to that terminal on the circuit board? Or should more than one of the speeds be connected? If that is the case, I don't know where to connect any of the additional wires.

should be designations for lo, med, hi on the board where the low is plugged in now.
motor should say which color is which speed.
you may have to crimp a connector onto the capped off wires to connect to the board
 
should be designations for lo, med, hi on the board where the low is plugged in now.
motor should say which color is which speed.
you may have to crimp a connector onto the capped off wires to connect to the board

I know which wires are for low-med-high coming out of the motor, but not sure for the circuit board.

I'll take a look at the circuit board tomorrow.
 
It is not uncommon , as has been said , for heat & cool to run different indoor fan speeds .

I personally would run it on high , Iif you can only connect 1 speed .

All this brought to mind , all the things that I take for granted / do automatically when trouble shooting , that the OP had to learn . And the tools I take for granted that he had to gather up .

I am blessed .

Wyr
God bless
 
This issue mostly occurs in an Air conditioner when the thermostat is not working properly, lack of power, or contacter problem. Check out all the mentioned issues and make sure they are working fine or you can call an expert to fix this problem.
 
Clear Duct System and Good Airflow | Common Air Handler Problems

Since the AHU is the central unit that moves the air throughout the ductwork it is important to make sure nothing obstructs the airflow through the air handler such as dirty or clogged air filters. A regular air filter maintenance schedule will help you maintain good air flow through the duct system. It also helps keep the air handler components inside clean and free of debris and dust. If you maintain good filter maintenance you will not have to worry about a dirty evaporator coil or any other components clogging with dust or debris. Furthermore, this includes closing off supply vents.

Blower Motor Failure | Common Air Handler Problems

The next most common problem that can occur with an air handler is a failure of a blower motor whether it be the blower motor or something else that causes the blower motor to fail. It could be a bad relay, control board, run capacitor or the blower motor itself. It could also be the blower wheel. These are AHU (Air Handling Unit) problems that need the attention of a professional HVAC technician. An HVAC technician can identify the problem quickly and make the repair. It may require ordering parts or the part may be available on the service truck but the problem will be resolved quickly and efficiently.

Proper Filter Maintenance | Common Air Handler Problems

Most of the issues described can be avoided with proper filter maintenance. Even the blower motor failure can be enhanced by bad airflow resulting from no regular filter maintenance. It makes the motor work harder creating more heat and pulling more amperage which costs you more electricity costs. The dirt from dust that builds up also hurts the motor and creates more heat which can have detrimental effects on the motor. Consequently, the lesson is to keep a good clean filter in the system and you will reduce any problems that may occur with your air handler.

Air Handling Units | HVAC Airflow

Again, it is recommended that an HVAC professional do this work. Make sure you read the High Performance HVAC disclaimer before proceeding. A professional will have all the proper HVAC tools to complete the HVAC repair or maintenance job quickly and efficiently. It does not matter what type of equipment you have. You can have a Trane, Goodman, York, Rheem, or Carrier HVAC system and it all needs to be maintained. If you decide to do it yourself make sure you follow the safety procedures as noted on the Air Handler Page about cutting power to the air handling unit before attempting to clean the evaporator coils.

Basic Check | Common Air Handler Problems

See condensate drain section below for more information on this subject. Soak the air handling unit evaporator coil with a soap and water solution. Professionals use an industrial strength coil cleaner which may be available at some hardware stores. Let this solution soak for a few minutes. Then take a rag and wipe as much dust off the surface of the evaporator coils as possible. Repeat these steps until the evaporator coils look clean. Take a flashlight and look between the fins on the evaporator coils. The evaporator fin on the coil should appear to be clean. If not, soak the evaporator coils again and use a brush with light bristles to brush the evaporator coils.

Checking the Air Handler Blower Motor | Common Air Handler Problems

The air handler blower is comprised of different components in most units. It has an electric motor, a squirrel cage blower wheel, and a cage typically referred to as a squirrel cage. Some air handling units have belt driven motors and most have capacitors for the air handler electric motor and typically the only required HVAC maintenance on the blower is oiling the air handler blower motor if it has oil ports or checking the belt if you have a belt driven motor. Not all blower motors have oil ports. These blower motors use sealed bearings and never require oil. The air handler blower motors that do have oil ports usually have little plastic dust caps that can be removed so that oil can be applied.
 

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