Wiring Thermostat for Swamp Cooler


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Old 04-25-24, 07:23 AM
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Question Wiring Thermostat for Swamp Cooler

I wanted to put my new swamp cooler on a thermostat, so that my house doesn't get too cold when I'm asleep or away. I thought it would be a simple matter of swapping out the switch, but it requires rewiring the cooler as well, and I've gotten myself stuck.

The old six position dial

The rear of the old dial, which had four wires attached to it: Red, blue, black, and black with some white dust/paint on it. Model RSK-2, Dial brand.
If I had been smart, I would have labeled the wires as I pulled them.

The new thermostat, MasterCool 110423-2. Backlight comes on when breaker is closed, but nothing on screen is shown and buttons do nothing

Wires behind thermostat. Note that the new thermostat uses red, black, and another wire, skipping blue (end wrapped in electrical tape) Also visible is two white wires connected with a wire nut, coming from the top. Each white wire comes from a different gang. They were not used with the old switch either, but the wiring diagram for that switch implys that is intentional.

Control box in cooler. This is a 120 volt pump and motor, with an additional purge pump. L1 and neutral are currently not wired in the power supply slots

Alternative picture of previous. to the left, there is a separate bank of wires, red, white, and black, which came up from the roof. The previous wiring and plugs also used a blue wire, which is not visible in this picture; it's bent out of the way. Yes, I'm aware I haven't hooked up all the grounds yet.

Wiring diagram for control box


The control box in the cooler has some testing LEDs, but they do not light up when pressing the test buttons. I'm obviously missing something, and I'm not sure how to move forward. I'm positive I need to wire the L1 and Neutral wires into the control box, but I am unsure of what they are, or if I would have to run new wiring. I find it strange that I need to add in more power, when I have the fairly large gauge wires on the far left in a separate bank of wires. I see that the blue wire is unused on the roof; maybe that was L1 and I messed up by not labeling everything. But it's not connected to anything in the house anymore, so I don't see how it would help.
 
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Old 04-25-24, 03:31 PM
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Welcome to the forums.

I thought it would be a simple matter of swapping out the switch
Not with the DIY wiring I've seen.
You must always document any wiring changes.

Wiring on old switch....
Red, blue, black, and black with some white dust/paint on it.
There will be 120v live source, high fan speed, low fan speed and pump.
You will need to confirm which wire does what before you can wire a new control.
 
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Old 04-26-24, 03:36 AM
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So would I wire it back up with the old switch and see what responds when run, then label it?
 
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Old 04-26-24, 01:49 PM
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If the old switch was labeled ..... then you should know what wire is which function.
 
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Old 05-01-24, 03:20 PM
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Update: Found out the problem after calling an electrician and having him fix it. The bank of three wires on the far left and the thermostat itself needed to be installed with thermostat wires, as they are low voltage circuits. The neutral and hot wires in the thermostat box were spliced together, and those were supposed to go to the power feed in the control box. A thermostat wire was run from the thermostat to the cooler.
After installation, the devices did not turn on or test, almost certainly because I had thrown 110 volts through a 5 volt circuit. Getting a replacement, and now that I understand the diagram, I can easily plug and play with a new unit.
 
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Old 05-01-24, 03:36 PM
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The actual wire type doesn't make a difference.
You could have low voltage on standard #14 wires.

That's why I mentioned DIY wiring.

At least you have the problem resolved.
 
 

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