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(320) 796-0851

Castair

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Dual Controls

What is it? Do I need it?

Dual control enables either start/stop or continuous air compressor operation, unloaded.

This eliminates excessive restarting during periods of over 50% duty cycles. Rather than turning off and heating up then restarting, it runs unloaded and cools down before resuming pumping or turning off. If no air is used for approximately 2 minutes (this time is adjustable), it will turn off and restart on demand when air is used again. Results are longer pump and motor life and lower electrical bills by eliminating excessive restarts. Note: In rush amperage draw at restart is 4 to 5 times the amp draw during pumping and amp draw during unloading is half of pumping amps.

Example: An 80-gallon compressor delivering 28 CFM capacity and an air demand of 50% (14 CFM) will run 1-minute 40-seconds and be off for 1-minute 40-seconds.

  • 1 min. 40 sec. (run time) + 1 min. 40 sec. (off time) = 3 min. 20 sec. cycle time.
  • 60 min./ 3 min. 20 sec. (cycle time) = 18 starts/hr

Normal operating temperatures:

Mode Pump Motor Amp/draw
Pumping 241 deg. 115 deg. 32 pumping
Unloading after 1minute 40seconds 192 deg. 98 deg. 16 unloading
Off after 1 minute 40 seconds 263 deg. 138 deg. 128 to 168 @ start-up

*As you can see it is better to just keep the unit running when demand is 50% or more. We recommend no more than 10 starts per hour for start/stop operation.

For continuous run mode, turn knob out, all the way to the left. For start/stop mode, turn knob in, all the way to the right.

dual control
Part # Description HP
DC1 Dual control on C1 pump 5 – 7 ½
DC2 Dual control on C2 pump 7 ½ – 10
C3 Dual control on C3 pump 10 – 15

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