Thermostat controlled Swamp cooler

[nayr]

I was requested to document this project, so here it is for everyone's benifit:

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3x RIB2401B Relays that work off 24VAC, which is what my Z-Wave thermostat signals with.. I just ran a 7 wire thermostat cable from my furnace to my swamp cooler to tie the signals in.. you only need 4 wires but I had to pull a new wire to thermostat because it needed 7 so I used the same spool

Relay #1: Blower On/Off
Relay #2: Blower Low/High
Relay #3: Pump On/Off

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Fan Only - Swamp Cooler blower on Low-Speed & HVAC Blower On (fixed speed)
Stage 1 Cooling - Water pump is on for evaporative cooling.
Stage 2 Cooling - Swamp Cooler blower on Hi-Speed.

My furnace blower is on when the Swamp Cooler is running, this is desired for my house so you can close a door and still get some air flow via room registers.. if you dont want this you'll want to hookup another relay or switch to toggle between swamp cooler blower and furnace blower.. I never run furnace when swamp cooler is open.. a big hole in my roof has to be sealed off manually so I just unplug the swam cooler at the end of the season when I fire the furnace back up.. I am either heating or cooling, never auto.

Thermostat's Cycle feature runs the blowers for 15mins every hour if temp is steady just to circulate/exchange fresh air and normalize temps across the different levels of the house.. all year long.