Water Usage, Single Accutrac 360-i In-bay w/ two high-pressure pumps
Peak Instantaneous Demand:
Hot Water: 7-9 GPM (7 during presoak, 9 during foam waterfall) Minimum flow is
2.4gpm. Should be softened to 0 grains hardness. Note: Tri-Foam & Foam Waterfall can
be run simultaneously for peak demand of 12 GPM
Cold Water: 80 GPM not including water softener regeneration or Spot Free Production.
It can be reduced with flow regulators to 45 GPM. Typically softened if iron is present or
hardness is above 10-15 grains
Spot Free Production: 8-10 GPM (3 or 4 membrane system)
Total Peak Instantaneous Demand = 60 GPM (80 GPM without flow regulators)
Average Water Usage
Hot Water: 3.0 to 7 gal/car depending on setup. Assuming 7 gals/car...
Short Bay w/Dryers, 18 cars/hr = 126 gal/hr or 2.1gpm
Long Bay or no Dryer, 30 car/hr = 210 gal/hr or 3.5gpm
Cold Water: 27.5 gal/car
Short Bay w/Dryers, 18 cars/hr = 495 gal/hr or 8.25gpm
Long Bay or no Dryer, 30 car/hr = 825 gal/hr or 13.75gpm
Spot Free Water: 9 gal/car
Short Bay w/Dryers, 18 cars/hr = 162 gal/hr or 2.7gpm
Long Bay or no Dryer, 30 car/hr = 270 gal/hr or 4.5gpm
Total Average Water Usage = 43.5gal/car.
Short Bay w/Dryers, 18 cars/hr = 783 gal/hr or 13.1gpm
Long Bay or no Dryer, 28 car/hr = 1,218 gal/hr or 20.3gpm
Normally, the high-pressure pumps are responsible for 60% of the total water
consumption. Softened water for hot water & R.O. consumes 40% of the total.
Hot Water Heater Sizing:
BTU’s/hr. required = Gallons/Hr x 8.33 x T 0.80(efficiency of hot water heater)
T (Delta T) is the desired temperature rise.
Hot Water Use per Pass:
Presoak Top: 1.0 gal/car @ 3.4gpm
Presoak Side: 1.7 gal/car @ 3.4gpm
Triple Foam: 0.8 gal/car @ 3.3gpm
HP Wax Top: 0.5 gal/car @ 2.4gpm
HP Wax Side: 0.8 gal/car @ 2.4gpm
Total: 4.8 gal (Best wash w/out Foam Waterfall)
(Add approx. 3 gallons/car with Foam Waterfall)
Hot Water Flow Rates
Min/Max instantaneous flow rates of 2.4 to 7 gallons/minute (12gpm w/ foam
waterfall & Tri-Foam)
Example: 3.5gpm for 7sec, 7gpm for 20sec, 3.5gpm for 5sec, 30sec dwell, 9gpm
20sec, 2.5gpm for 20sec
Estimated Average Hot Water Usage (no waterfall): 4.0gal/car x 29car/hr = 116gal/hr.
116gal/hr x 8.33 x 70 deg. rise 0.95 efficiency = 71,000BTU
Max usage if every car received wax: 4.8gal/car x 29car/hr = 139gal/hr. = 85,000BTU
Hot Water Use with Foam Waterfall: 7.8gal/car x 22car/hr = 171gal/hr = 105,000BTU
Spot Free Re-pressurization Pump: Pressure vs Actual Flow
250 psi = 31 gpm
200 psi = 28 gpm
175 psi = 26 gpm
150 psi = 24 gpm
100 psi = 20 gpm