Not sure if anyone has tried & thoroughly tested the
Cat Pump or KR variable pressure gun besides myself ... but somehow we have them working out at our location & we have had compliments from some customers about that fact they can let up on the trigger to get less pressure. The "dump gun's" plunger does have to be kept free with WD40 as needed ... usually every few months ... pretty minor as far as maintenance is concerned. So our bays are all "up to 1500 PSI" but not if the customer prefers less. Granted ... with the trigger let up ... there is slightly more water used but the Cat310 - 3HP combo limits that to not much more water. Someone on this forum has remarked in the past that water dumps on the customer's foot ... that has not been our experience with those specific dump guns.
http://car-wash.kleen-ritecorp.com/search?w=dump gun
When we have a extra muddy clean up situation ... we use our 1/2" hose reel & pull out a special gun with a 2508 nozzle using as many as 4 pumps from a 7 pump manifold we built over 25 years ago. The water volume is definitely a factor in its effectiveness!
mike walsh
www.kingkoin.com