I inherited 3 sites each with multiple sprinkler systems (2 or 3 depending) on "plant air". The problem is the compressors assigned to deliver said plant air are only robust enough to air up a single component system within 30 minutes.
During the fall, we experience drastic temperature drops at dusk that result in pressure drops across all systems simultaneously, that effectually over-task the lone compressor at each site. The compressors run until the overtemperature cut-off pops, and they've been leaking oil from the head gasket due to overheating.
I'm perfectly willing to buy a $5k compressor, but they're typically 3 phase. I'm also willing to buy 2 or 3 small compressors/riser and cap the plant air line, but in either case the greater expense is running AC power to the risers, or upgrading the current plant air circuit voltage.
A permutation of the above 2 options would be to run 2 -$700 compressors in parallel at the current plant air site to split the CFM output requirement. I would have to run a 2nd dedicated circuit to the existing compressor locations, but it's in relatively close proximity to the panel.
To do so I am assuming I would need to wire the on/off pressure switches to an air maintenance device. I need them to come on and cut off at the same time, or else one will run to failure, the pressure bleed down, then the redundant compressor will run to failure. I'm worried that modifying the new compressors will void their warranties (which I acknowledge I may have to live with).
Does anyone have a diagram and parts list for how to use 2 compressors in tandem? Any recommendations for most pragmatic fix?
Thanks in advance.
Posted anonymously for discussion. Discuss This | Submit Your Question | Subscribe
Subscribe and learn something new each day:
Thank You to Our Top
February '21 Contributors!
Sprinkler Designer or Engineer?
Get all of our tools, including the Sprinkler Database, Friction Loss Calculator, Fire Pump Analyzer and more:
Daily discussions are open-ended fire protection, fire alarm, and life safety questions submitted anonymously for the benefit of sharing expertise and learning from other perspectives. Anyone can submit a question here:
2020 PE Prep Guide
PE Prep Series
2020 PE Prep Series
(Click to enlarge)
Visit July-October for daily Fire Protection PE Exam sample questions.
Solutions are posted the day after posting.
Comment with your solutions, questions or clarifications.
Please note that questions posted are unofficial and in accordance with NCEES rules are intended to be similar to actual exam questions, not actual exam questions themselves.