Originally Posted by Orman
The HH heating element is only heating as needed, not all time, It has it's own thermostat.
True. But the OP has times during the day that he does not want the element to heat, but also wants it to heat at other times of the day. As he will not be in the coach to turn on/off the element when he wants the heating to be on/off, he is looking to add the timer.
I do understand what he is trying to do.
For us, and everyone does things differently, we usually find that if we turn on the element when we first get up, or first return to the coach from a day trip in the late afternoon - the water becomes hot enough to support what we need. We have the single element in our coach, so usually need to augment the electric with diesel when both taking showers.
On colder nights, we've had good luck with heating the coach with only the single element HH on. When needed, we will add a single portable electric heater in the front of the coach, setting the thermostat zone of the coach quite a bit lower. Finally if we have 50 amp service and are not paying for the electric above our sites fee, we use our radiant floor heater, and find it supports us with in the sleeping quarters, and then we augment the front with only the portable heater. Our HH fed heat exchangers, have the louder then we like to hear squirrel cage fans, so we try to not use that heating options if we can avoid it.
Finally, we have the Heat Buddy, and have added an inside LP fitting to tap into the large tank of the coach. Don't use that as much inside this coach as we did our Bounder, but have it if needed.
(More info then needed on this thread, but was trying to explain how we use our HH and it's electric element, and that kind of ran into the heating of the coach too
Best to all, be safe, have fun,