Just checking on hot water

[Michael Hannan]

Do I have it right that when the hot water on hand runs out the diesel heat is supposed to kick in?  Mine isn't so I want to if I should add it to my fix list for the RV repair tech coming out next week.

Thanks
MJ

[Keith Moffett]

Mike
Turning on the electric side only of the AH will not activate the diesel even when the water temp drops.  The diesel must be activated but when the water temp drops now the diesel kicks on.  If the diesel side is activated but still doesnt come on then see if it activates properly from the thermostat. 

[Michael Hannan]

Thanks, Keith.  If starting the diesel side on is more than just turning the diesel burner switch on then I need to read up on it.  Now I now that I understood correctly if the setup is correct.

MJ

[David T. Richelderfer]

I do not know your model of AquaHot, but ours is the AHE-100-02S.  We have two switches - one for the electric water heating element and it's found in the main 110v electric panel in the bedroom; and another switch for the diesel burner water heater and it's found on the exterior face of the upper cupboard over and forward of the galley sinks.  I can have any combination of switches on or off - both off or both on, or one on and one off.  Each switch has a pair of thermostats in the AquaHot for turning its system (diesel or electric) on and off.  The diesel burner thermostats (on at 190F and off at ~210F) actuate at about 10F to 15F degrees cooler than the electric thermostats (on at 198F and off at 230F).  The diesel and electric water heating systems are separate, therefore they operate by separate on/off switches and are controlled by separate on/off thermostats.

The HydrHot is a complex system with many systems and pumps.  There are many things that can cause problems.  The HydrHot also has a system for pre-heating the engine.  That switch on our coach is found right beside the diesel burner switch over the galley sinks.