I built a system for foam brush and presoak guns several hundred years ago.
It’s been quite effective at preventing freeze ups at temps well below zero.
I contemplated using the same system for the high pressure guns. It will work as long as spot free rinse doesn’t use a shared repressurization pump...mine did, so I shelved that project.
The system blows out each bay, injects windshield washer fluid, and blows out again.
After each use, that bay’s system gets another cycle.
In summer, the system operates the controlled devices with no delay. In winter, product delivery is delayed to prevent unnecessary protection cycles due to customer simply passing through the selection.
I assembled the 8-bay system using IDEC SmartRelays with expansion modules for the additional I/O requirement. Smaller car washes might only need one SmartRelay.
Idec’s current 24volt AC SmartRelay series (FL1F-H24RCA) sells for about $160 with Expansion modules being about $100 each. Idec devices are rebranded Siemens LOGO with a slightly lower retail price. Idec is easier to find online at Allied Electronics and Wolfe Automation.
The FL1F is an amazing logic device with impressive features...including an
app for monitoring and controlling from your mobile device or computer!
I visited the facility today to assure the new owner that the freeze protection system was ready for tonight’s hard freeze. Still working perfectly...with over 1.5 MILLION inputs recorded.
The complete system needs a
Flojet pump, an “anti-freeze” solenoid manifold and drum and all the PE tubing and fittings. Product tubing should be plumbed to the bays inside a heated trough/duct for the most efficient delivery and protection.
While it's unlikely that I recall correctly but I think I spent about $1,200 for the 8-bay fb system components. Since I used Idecs for water softener control, facility lighting, boiler control, and other “gadget” projects, I already had the extra cost programming software.
Obviously, there's a learning curve if you're not PLC savvy ...But, Idec/Siemens function block programming is reasonably easy to figure out. There's even a 300+ page manual and online help to assist with all the Ands, Ors, Nors, and Nots.