chevyx92
Senior Member
- Location
- VA BCH, VA
What's the best way to control two 25 HP air compressors that share one big holding tank? Just individual pressure switches on each compressor? How would you install control to alternate them?
Multiple Air Compressors
- Thread starter chevyx92
- Start date
- Status
kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
First is the air demand ever high enough that both need to run simultaneously? Not impossible but does complicate it a little more.
Otherwise if always only running one unit and for the simplest controls, you can either install an alternating relay that switches back and forth each time a run cycle is initiated, or you can use a timer control and set up so that it switches back and forth daily, weekly, monthly, etc.
If you want second unit to automatically start up if the first one should fail, you need a pressure switch that when a low limit is reached initiates starting the second unit, gets a little more complex if it starts either unit as the second unit then if you have the two permanently staged to start at different pressure levels.
Otherwise if always only running one unit and for the simplest controls, you can either install an alternating relay that switches back and forth each time a run cycle is initiated, or you can use a timer control and set up so that it switches back and forth daily, weekly, monthly, etc.
If you want second unit to automatically start up if the first one should fail, you need a pressure switch that when a low limit is reached initiates starting the second unit, gets a little more complex if it starts either unit as the second unit then if you have the two permanently staged to start at different pressure levels.
All compressor manufacturers offer sequencing controls for this purpose. There are 2 pressure set points, one slightly lower than the other. If 1 can't keep up, the pressure falls to the lower set point and the second compressor starts.
Once demand is satisfied (both compressors shut off or unload), the next time a compressor is started, the alternate is started first. The theory is to equalize run time between the compressors.
Google "lead-lag compressor control".
Once demand is satisfied (both compressors shut off or unload), the next time a compressor is started, the alternate is started first. The theory is to equalize run time between the compressors.
Google "lead-lag compressor control".
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