Water capacity question.

[klutchdust]

So I wonder about this as I am filling up my coach.
I ran the hot water until there was none left. So my water heater is empty, correct. It holds 6 gallons of water. Now, lets say I fill my water tank and take off, when i turn on my pump 6 gallons will go into the heater and then maybe another gallon to charge the other lines? So I am 7 gallons down and haven't done anything yet. Every gallon counts when boon docking in the desert.

Now, I attach my hose and go inside and turn on all faucets and add some to the toy let. Then before I disconnect I turn on my pump until it shuts off then add a little more until the overflow spills.

Am I just amusing myself or actually doing something to ensure i have as much on board as i can hold.

JD, miss you buddy.......

[klutchdust]

Great feedback, thanks guys.

[bobndot]

SDcampowneroperator wrote:
No, you will not run the water heater empty when you pump empty your supply tank. Water heaters of any kind fill with cold through the bottom inlet, give heated water out the top. Heated water rises so does air.
When your pump runs out of water to pump into the system, the water heater is still mostly full, as any air it might pump will rise to the top,then come out your hot water tap, so might make you think it is empty. Go open the drain, to prove it.

Ditto.

[BFL13]

Before going, open the drain on the fresh water tank to empty that. Turn off the water pump (do that!), and open the hot water tap at the kitchen sink, go out and take out the plug on the water heater and drain that.

When all drained, leave the pump off, put the water heater plug back in, start to fill the fresh water tank, leave the sink hot water tap open. Watch the monitor, when the fresh water tank is about half full, turn on the water pump.

Wait till the air comes out of the hot water tap and it runs full flow--that means the hot water tank is now full. Close the hot water tap. Keep filling the fresh water tank.

When all done, empty the grey tank so the water you poured down the sink with the hot tap still open is drained, leaving you max room in the grey tank before you go.

Also now it is full and pressured up, confirm your hot water tank plug is in right and not leaking any.

[Lwiddis]

“I ran the hot water until there was none left.”

Nope. Draining the hot water heater is accomplished by opening the valve at the HWH, not by turning on a faucet. Fill the fresh water tank, turn the water pump on, turn on a hot water tap, wait while the HWH fills and water comes out of the faucet, turn off the hot water faucet, and fill the fresh water tank...6 to 7 gallons. Elementary, my dear Watson, elementary.

[TenOC]

klutchdust wrote:
S
I ran the hot water until there was none left. So my water heater is empty, correct. ....

No. The water heater is still full of cold water. Your water line are also full, unless you "blow them out". The only way to empty the heater is to open the drain plug.

To get the maximum amount of water check where the fresh water tanks vent/overflow pipe is located. On my 5er it was located so that I lost almost 1/3 of the water as it sloshed around going down the road. I had to re-route the exit of vent/overflow line to a higher location.

[SDcampowneroper]

No, you will not run the water heater empty when you pump empty your supply tank. Water heaters of any kind fill with cold through the bottom inlet, give heated water out the top. Heated water rises so does air.
When your pump runs out of water to pump into the system, the water heater is still mostly full, as any air it might pump will rise to the top,then come out your hot water tap, so might make you think it is empty. Go open the drain, to prove it.

[Terryallan]

klutchdust wrote:
So I wonder about this as I am filling up my coach.
I ran the hot water until there was none left. So my water heater is empty, correct. It holds 6 gallons of water. Now, lets say I fill my water tank and take off, when i turn on my pump 6 gallons will go into the heater and then maybe another gallon to charge the other lines? So I am 7 gallons down and haven't done anything yet. Every gallon counts when boon docking in the desert.

Now, I attach my hose and go inside and turn on all faucets and add some to the toy let. Then before I disconnect I turn on my pump until it shuts off then add a little more until the overflow spills.

Am I just amusing myself or actually doing something to ensure i have as much on board as i can hold.

JD, miss you buddy.......

Doubt your water heater was empty. Just out of hot water or no pressure. To drain the water heater. you would need to take the plug out, or in some cases. Open the low point drains, and open a faucet, or the relief valve.

[camperdave]

I don't understand how you drained the water heater. If you turn on a hot water faucet without the pump on, nothing will come out, right?

[donn0128]

Fill the HW heater, run water thru the lines, fill the tank. Now your ready to go.