Bear with me gentlemen as I respond to 'Big Bill'...
Ron was mostly correct but not quite...500 gallons only has 400 usable for almost any position of the tank/trailer, so run time at 10 GPM is no more than 40 minutes without make-up water. Most municipal water supplies can give 6 GPM easily, rural 4 GPM. At 6 GPM you would experience a run time of no more than 44.44444 minutes without running dry.
By the way running dry is a bad thing.
Where does the water bypass if there is no float tank? Back to the main tank? Then why have an auto-shutdown system? How can you run a timer shutdown for the engine without electricity? Does the pump decouple from the drive when a bimetallic thermostat senses high temperatures? Does this not add needless complexity and potential for failure? Who certifies the technicians building the machine? Do they meet CETA (voluntary, non regulatory), UL (US voluntary regulatory) or CSA International (Canadian mandatory) standards? If not why?
Who handles warranty on the Intermitting (sic) Duty Cycle? The pump manufacturer won't. Pump and engine warranties are void if any accessory outlet is attached to the oil crankcase, period.
Beckett rates the SDC burner at 300,000 Btu for 12V operation. Regardless of the famous purple wire that every Beckett burner has and smart manufacturers use, that is the limit with 140 PSI fuel pressure and a 1.75 80A nozzle but most importantly the limit of the squirrel cage to supply air. Why do you need a pressure gauge on your burner anyway? Changing this will change the burn characteristics of the coil as negatively as changing out the burner nozzle: green smoke indicatiing incomplete combustion and poor air quality. Bad thing in this era of clean air legislation.
How do you fill those great big fuel tanks buried in the base? How do you monitor fuel level? Should you not fill up beofre every job from DoT approved containers? Check your engine oil level? and so on? Is pressure washing such a high dust profession that you need dual stage air filtration? Small engines rarely fail from intake problems, they almost always fail from lack of oil problems which could be exacerbated by accessory drain methods not supplied by the manufacturer.
On 115V machines, is there enough excess capacity to meet the start demand of the ADC burner and still plug anything in? Does it supply a regulated output to prevent blowing up whatever is attached? If generators were as simple as running them and plugging them in why is there all of that extra hardware on dedicated gensets?
As to performance...25 HP is plenty to do 6.8 @ 3500 using the formula supplied by Cat Pumps of (flow x pressure)/1460=Electric Brake HP (EBHP is a quantifiable, repeatable, World-wide standard). EBHP x 1.5= gasoline engine HP (this is a best 'real world' number based on the fact that there are no standards in small engines on performance).
If the SDC burner is properly set up and there is a large enough charging system and you use an automotive battery then you only need one to start and run the 12V system, unless you are running too many tertiary (look it up) devices like switches and the associated lights.
Now to the trailer and tow vehicle... best guess the IH will weigh close to 1000# dry, add 175# for fuel and oil, add 300# for a 500 gallon tank, 4000# for water, 200' of garden hose at 75#, 200' of HP hose at 125#, hose reels at 100# complete and 225# of soap, wands, accessories et al you should have close to 6,000#. Add in 1,500# for the trailer and you have a Gross Weight of 7,500# MINIMUM. This really limits your choice of tow vehicles.
So as I understand the numbers... 25 HP is not enough for 8-10 GPM at more than 2500 PSI, 300,000 Btu will not raise 8-10 GPM 160 degrees from ambient to give you the mythical 210 outlet, there is not enough run time to be useful with the supply tank (600 gallons would have 480 usable or 48 minutes of cleaning time plus add 800#), you would need to placcard your vehicle if the fuel tanks met DoT rules and were full, you are on your own for warranty and service support and so on.
I guess there is no benefit to getting an IH?
I cover a wide swath of the US and have never run into a dealer of IH pressure washers (from the Atlantic to El Paso to Duluth to Brownsville).
You spends your money you takes your chances.
Sorry gentlemen for the long wind but as you may know I do have a real problem with people that obfuscate and obscure the truth and seek to deceive the public.
Cheers.
