Motors and switches wiring can change from different manufactures. Be sure to always follow the schematics from the manufacture for any motor or switch.
A swamp cooler needs Power to run two things.
- Blower Motor
- Water Pump
The water pump is what pumps water up to the cooling pads and is almost always 110/120 volts AC and like any 110/120 volt appliance it simply needs to be plugged in to work.
It will operate like any 110/120 volt appliance once it is plugged/wired into a cooling unit.
A blower motor blows air into a building and can be either 110/120 volts AC, or 220/230 volts AC, and will also have connections for low and high speeds.
Here is a swamp cooler blower motor with the leads for Hi, Low, and Common labeled H, L, and C.
When voltage is applied to the low side the windings in the motor it will turn the motor slower. When voltage is applied to the high side the windings in the motor will turn it faster.
Swamp Cooler Wiring Color Codes
- Red = low
- Yellow = Pump
- Black = Hot Wire (High)
- White = Common Wire (Neutral)
- Green = Ground Wire
While the hot wire (black wire) goes through a switch to the motor, the common wires (white) are all tied together to complete the circuit when the switch is flipped.
An evaporator switch is the most common way of controlling a swamp cooler, although thermostats can also be bought to control a cooler.
Single switches are also sometimes used with a single motor speed and the pump simply tied into the switch.
An evaporator cooler switch is a much better option since it can change from low to high speed as well as fan and pump only.
The above is a basic wiring schematic for a swamp cooler switch. (Always follow the schematics that come with the switch that is bought, this is only an example.)
On the left side is the wiring coming from a breaker with Black (hot), White (common), and Green (ground).
Ground: The Ground wire is simply connected to all the grounds with a wire nut.
Common: The common (neutral) wires, usually white, are all connected together including the common side of the water pump.
Hot: The Black wire or hot side is connected to the switch and will give power to the proper setting when the switch is turned.
Here is an example of a 110/120 volt swamp cooler switch that is wired in.
- L1: This is the hot wire (Black) coming from a breaker.
- 1: Red wire coming from low side of blower motor.
- 2: Yellow wire going to hot side of water pump.
- C: Black wire going to high side of blower motor.
The switch will have the low and high side from the blower motor connected to it along with the hot side of the water pump.
As you can see from the simple diagram above the only real worry to focus on is wiring the hot side (black wire) correctly into the switch.
The wires coming from the hi and low side of the motor need to be connected properly as well as the hot side from the water pump.
Since the common wire (white wire) simply completes the connection it does not need to run through the switch. The same with the ground (green) wire.
Keep in mind that simply because wiring color coding is supposed to be followed, Black (hot), White (Common), it is always a good idea to double check. Especially in older homes where the wiring may not have been done correctly.
If you are replacing a switch or doing a new install from scratch yourself this will not be a problem, as you will be able to spot if the wrong wire color coding is being used.
Where Can a Swamp Cooler Switch be Bought?
Swamp cooler switches can be usually be bought at any hardware store. They can also be bought online at Amazon or eBay.
Example Swamp Cooler Switch On Amazon
LASCO 36-0233 Evaporative Water Cooler Thermostat with Two Speed Six Position Switch