Mark says "everything cleaned with 171 degree
hot water, which can't be reached with a normal hot water heater"

Are you sure?  My heater, powered with natural gas, produces at 180 degrees.
I think the maximum temperature is a function of:

A. The thermostat setting that can be reached with the knob.  That can
usually be changed with a screwdriver and the instruction manual.
B. The pressure relief valve that contains a "gizmo" that is melted (?) at a
certain temperature, to prevent the water heater from blowing up if the
thermostat gets stuck and fails to turn off the heat source.

My understanding is that this valve can be changed or modified to
accommodate higher than normal temperatures.  Check with the manufacturer or
a high-quality plumbing supply house.

Hope this helps

Lloyd
Mailto:[log in to unmask]
Lloyd Spear Owner, Ross Rounds, Inc.  The finest in comb honey production.
Visit our web site at http://www.rossrounds.com.