Voids The Warranty!!
If you're talking about the 'Hott Rodd' or similar device, it's use will void the warranty on new heaters. The idea is sound, but I have seen folks with problems and removed them. Thermostatic control failure is usually the culprit.
If you are using it on a Suburban, it has to replace the anode in the drain plug which protects the tank from corrosion. I would NOT recommend this for a Suburban.
Check with Atwood and they will say that they also don't suggest them.
Lew Farber...RVIA Certified Master Tech...ABYC Certified Master Marine Electrician
SOLAR TECH ENERGY SYSTEMS, INC.
AM SOLAR ...MAGNUM…VICTRON ENERGY...LITHIUM & LIFELINE BATTERIES…MARINE REFRIGERATION