It comes with 3 relays and fuses to run the fans high/low, weather pack connectors high quality stuff well worth it. And can set temps to whatever you want, also has A/C input to trigger fans high via tri switch. Also has extra inputs to run the fans high or low manually.
The controller is smaller than a business card.
Running one fan at time will not help the A/C cool correctly as you have half the air flow over the condensor so you lose basically half your cooling ability. it won't be efficient cooling at idle on a hot day. Why even have dual fans at that point if one is off most the time, above 20 mph they both are off anyway most times.
Ideally want both fans on low then high as needed. You'll never hear them on low over your exhaust most times.
I run the controller above and works great!
Thanks for posting.. That is a quality fan controller with many options.
I have found that the DD2750 can be set to 3 degrees between the on and off temps instead of 10 degrees for the HPC. I just don't like to see those big temperature swings, especially here in Texas summers. It worries me to see the gauge climb past thermostat temperature. The DD also uses the gauge sensor instead of a separate sensor, so you don't need an extra port.
Usually on hot days your fans on high for A/C anyway. With AC off mine usually never runs high on hot day. So you won’t see the 10 degrees anyway.
You want low fan turn on 10* above thermostat temp. This way its not fighting the stat. So if stat is 190. Fan low is 200 on and off at 190. High is 210 on and off at 200 back to low how the HPC works if set to close it may be fighting high and low. The 10* flat works mine never goes over 210 on 110* humid day with A/C on zero issues.
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