[djenkins299]

My husband is changing a 1 pole contactor to a 2 pole contactor on our air conditioner. The problem is he is not sure which wires go where. Could you please help.

[buzzman]

There are two parts to a contactor. The control circuit and a power circuit. The contactor allows you to control a device through "indirect switching". What I mean by that is you can have a 120V rated switch operating a 240V device. The contactor allow you to have this kind of control. To explain the first part of the contactor, you CAN use a 2-Pole contactor in place of a single pole contactor, but you cannot go the other way around. The contactor will be labelled with an "L1 & L2. This designation is where the wires are directly terminated (Attached) from the main source (Panel). The bottom of the contactor are usually labelled as a "T1 & T2. These points are designated for wires that run from contactor to its device, which in this case, is the Air Conditioner. In this case you will be omitting one pole because you only need one. You will only be using the "L1" and T1" terminals. The other two will be left with nothing on them.
The second component of the contactor is the coil. This is the "control" part of the contactor and it causes the opening and closing of the "contacts between your "L1/T1" and "L2/T2", thus causing the unit to turn off and on as the AC unit cycles the "coil" accordingly through its thermostat switching. These are usually labelled as an "A1" and "A2" or will simply state the connection points as "Coil". The coil has a voltage rating. Double check that the 2-pole contactor matches the 1-pole coil rating, or the device will not operate properly. The rating on the coil to a unit such as yours should be 120VAC, but sometimes the newer models will use "Low voltage switching that can be rated at 24VAC. Be careful of the ratings so that everything matches the original contactor's ratings. Putting 120VAC to a 24VAC rated coil will cause "smoke to be released". Thus the death of the coil.
By you telling me that this is a single pole device, it tells me that the operating voltage is 120VAC (Voltage "AC"). it sounds like a smaller unit, possibly a window unit . An easy way of making sure you have a guide when you change out components is to turn power off to device completely. Then cut wires (Not de-terminate). This allows you an idea of where the main wiring goes to the components without tracing them out by hand which can be tedious and next to impossible if you are not qualified. If you cut the wires off on the old unit, it is a matter of matching the wires onto the new device of course minus the wires on the "L2" and "T2" designations. FYI the 2-pole contactor would be used for a device with operating. Let me know if you have any more questions.

[acetc]

When changing the contactor in your air conditioning unit you should first take note of where the wires are connected to the contactor, draw a picture. The contactor will have two control wires that come from the thermostat and connect to the coil of the contactor, they will be 24 volts. The two line voltage wires coming from the disconnect (fuse box) will connect to the two screws or terminals on the same side of the contactor, the wires that you removed from the opposite side of the contactor will connect as before.
Now the difference between a single pole and a double pole contactor is a single pole only has one set of contacts and a double pole has two sets of contacts, now you want to put a jumper around one set of contacts to make it act like it were a single pole contactor, do this to the wiring that goes to the capacitor , this provides for the warming of the oil in the compressor during the off cycle. Single pole contactors used in most air conditioning units have two terminals on both sides of the contactor to connect the line wires and two terminals to connect the load side wires.
Be sure to disconnect power to A/C before working on it, Good luck. Mike

[hvac1000]

The constant on (jumpered contact) on the contactor/starter is used to allow 115 volts to pass into the compressor windings to act as a crank case heater. Make sure you wire it correctly.

[ununpentium]

The contactor will be labelled with an "L1 & L2. This designation is where the wires are directly terminated (Attached) from the main source (Panel). The bottom of the contactor are usually labelled as a "T1 & T2.

The label has been worn off my dipole contactor and I cannot determine which side is L and which is T. I have a handmade diagram showing which wires connect to which positions relative to each other, but I don't know if I have the contactor reversed or not. Does it matter which side I treat as L1/2 and T1/2 as long as I have the A positions correct? Will it work either way? Thanks.

[hvac1000]

All a contactor is a switch. Very simple in design.