Difference on heat between 3 ht heater and 4 ht heater?
Steam coming out of a wand isn't that great of an indicator, actually. It just indicates a rapid rate of condensation, which doesn't require a starting temperature of above "boiling" to happen.
If you hear your wand "pop" at the jet(s) when you pull the trigger, then you're above the boiling point of water at the jet. But it's still not a solid indicator of precise temperature.
A #3 Little Giant delivering 180 degrees consistently is only possible in summer time weather, with small jets in the wand. But with an effective jet size of 6 or more, you simply won't get a dependable 180 even... much less anything more.
Basically, with a #3, you'll get 160 to 170 consistently with normal wand trigger action. Of course, if you do a cleaning pass of one stroke, followed by a drying pass, followed by another cleaning stroke, the #3 will maintain 200 degrees. But it's not practical to clean that way.
The longer you keep the wand keyed, the lower the temperature will be, until it flatlines at about 170 continuous degrees at 1.5 GPM. or thereabout.
A number 4 will do more... but nothing like a larger propane or oil- fired system will do.
To be more precise:
Average wintertime input temperature is approximately 45 degrees. Average summertime input temp is about 65 degrees.
The 3HT gives a rise of 120 degrees over the input temperature at 1.25 GPM (That's about 250 PSI through a #6 jet size.)
The 4HT gives 120 degrees rise over input temperature at 1.87 GPM (About 400 PSI through a #6 jet.)
So, if you turn your pressure down on a #4 to, say 300 PSI, you'll get closer to that "above 200 degree" target you're looking for.
Duane Oxley
http://interlinksupply.com/spec_sheets/ax41_hotomatic.pdf
^^^
