Unfortunately, it does seem to be trial & error. The equipment most likely changes with the product line & most certainly from Class C to Class A.
My tank does take a while to drain as well. Generally pull all 3 valves & go to bed (or find something else to do for a couple hours). What I'm saying is that one of the valves is on the faucets side of the water pump (rather than your tank side). Make sure your faucets are all turned off, open this drain that goes to the ground outside & turn on your water pump. Water should gush out of the drain onto the ground. Your tank will be emptied in matters of minutes. Just stick around to shut the pump off shortly after empty because the pump is cooled by the water. I'd guess you could burn it out running it dry.
About your hot water tank: It shouldn't drain dry because of the anti-backflow valves. But, you are wise indeed to be concerned. Turn off the water heater at the kitchen control/status panel to prevent the propane from coming on. Never never Ever ever leave the electric element on if there is a chance of emptying the hot water tank. They say its less than minutes before the element burns out! You know there is a circuit breaker behind the external panel that covers the water heater controls & exhaust. If there is the slightest chance that someone could turn on the unmarked switch in your MH, then turn off the external circuit breaker.
Next question I have is the purpose of draining the plastic water tank? If it is to winterize your unit, you know that you MUST take specific steps to drain the heater? Please forgive me if you consider this is a stupid comment, but I keep thinking about the lack of detail of my PDI. The dealer would have prefered that I drive 100 miles each way to have him do my winterizing each year, for a fee. So, I find it most responsible of me to just mention some of these little things, because it wouldn't be so little if you cracked your tank.
|