How to retrieve that 6 gallons in the hot water heater?

[esimmers]

I love having the six gallons of water in the hot water heater but I'm wondering how I'd get access to that water if my 20 gallons tank ran dry. It seems there's a back flow valve on the hot water inlet so it won't drain back into the system and of course without more water to pump in, it won't pump out.

I do have my handy 15/16 socket to remove the drain plug on the outside of the camper but there's got to be a better way.

Any ideas?

 

[DesertDave]

On my new Grandby, I think all I have to do is turn single valve to drain the hot tank into the storage tank via gravity. It is listed in my owners manual. I did this when I was cleaning the system up after purchase with chlorine, and once since to change out the water. If I ever have to winterize this is part of that process.

If I ever needed the last six gallons of water I would do this, then be sure to only use the cold tap.

 

[Chukar Hunter]

on my 07 Hawk I install an anode that has a petcock on it. I drain my hot water tank after every use just open the faucets and the drin valve and it flows out. To capture that water a small tube would work great

 

[jha6av8r]

Why not just run the faucets on the hot water setting. That's what I do. You always have access to all 26 gallons of water whether hot or cold.

 

[DesertDave]

Why not just run the faucets on the hot water setting. That's what I do. You always have access to all 26 gallons of water whether hot or cold.

I have read on here that once the main tank runs dry the pump won't push the water out of the hot water tank. I think this makes sense, only because I also think the hot water tank is 'upstream' of the pump, and the water pump isn't so good at pushing air.

I haven't tested it, and thinking something is true doesn't make it so.

 

[jha6av8r]

I have read on here that once the main tank runs dry the pump won't push the water out of the hot water tank. I think this makes sense, only because I also think the hot water tank is 'upstream' of the pump, and the water pump isn't so good at pushing air.

I haven't tested it, and thinking something is true doesn't make it so.

Dang it. Now I have to test.

 

[Bwht4x4]

The hot water tank is upstream of the pump. If you open up the cabinet door to access the water pump and start looking at the routing of the pipes you'll see. I thought about this issue, water getting stuck in the hot water tank, but I haven't done much to see if I can do anything about it.

 

[Wandering Sagebrush]

The hot water tank is upstream of the pump. If you open up the cabinet door to access the water pump and start looking at the routing of the pipes you'll see. I thought about this issue, water getting stuck in the hot water tank, but I haven't done much to see if I can do anything about it.

Unless I don't understand your post, I don't see how that could be.

If the HW tank is upstream of the pump, that would mean the pump is running hot water through it. On all of the RVs I've owned, the pump is between the main fresh water tank and the hot water heater. Water from the fresh water tank is pumped through the system to the faucet, and into the inlet side of the hot water tank to replenish water as it is used at the sink or shower.

Once the FW tank is empty, about the only way to get the remaining water out of the water heater is to either drain it by pulling the plug, or to use air pressure to push it out of a faucet. Caveat... I believe that some water heaters do have a drain line, but I suspect most do not. You just pull the plug.

 

[coguzzi]

there are 2 valves close to the pump for the hot water tank.

one valve can totally isolate the hot water system (for those quick trips that you do not need hot water). closed it will not fill the hot water tank, open it performs as usual.

the second valve is on the drain circuit. closed it allows water to STAY in the hot water tank (normal operation), open it allows the water in the tank to drain back to the fresh water tank. this is how you drain the system when your home, or winterizing. BUT, you can also think of it as 6 gallons of water storage--free water.

it is true you can not pump when the fresh water tank is empty (wont pump air well), but drain that water back into the fresh water tank and you will be able to pump then.

PS-again, normal water system draining/winterizing procedure. i completely drain my system everytime i return, i dont like stagnant water sitting in my camper

 

[Bwht4x4]

WS,

Sorry for my description, I guess I knew what I meant in my head. You are correct that the pump is between the freshwater tank and hot water tank. In my camper there are two valves. When one is open the pump will force water to both the cold side of the faucet and the hot water tank. If that is closed it will isolate the tank and prevent water from going into the tank and will then only feed the cold side of the faucet, as coguzzi said. Also as coguzzi said the second valve allows water to drain from the hotwater tank back to the main tank. It drains slowly unless I open the faucet to the hot side to release the vacuum. As coguzzi said I also think of and use the hot water tank as water storage. Before a trip I make sure both the hotwater tank and main tank are filled.

 

[camelracer]

there are 2 valves close to the pump for the hot water tank.

one valve can totally isolate the hot water system (for those quick trips that you do not need hot water). closed it will not fill the hot water tank, open it performs as usual.

the second valve is on the drain circuit. closed it allows water to STAY in the hot water tank (normal operation), open it allows the water in the tank to drain back to the fresh water tank. this is how you drain the system when your home, or winterizing. BUT, you can also think of it as 6 gallons of water storage--free water.

it is true you can not pump when the fresh water tank is empty (wont pump air well), but drain that water back into the fresh water tank and you will be able to pump then.

PS-again, normal water system draining/winterizing procedure. i completely drain my system everytime i return, i dont like stagnant water sitting in my camper

This is not true with all FWC campers. My '06 Grandby doesn't have manual valves in the hot water tank circuit. It does have a check valve between the pump and water heater. I'm not sure what year they made the change.

 

[esimmers]

Thanks everyone for helping me figure out how to retrieve the 6 gallons of hot water from the water heater in an emergency when the main tank is empty so the pump can't push the hot water out of the heater. I have a 2009 Hawk. There have been different plumbing systems installed by FWC over the years which may make your system different.

The current system is like coguzzi describes: two valves inside the access door near the bottom. One is normally open so the pump pushes water into the hot water heater. This valve can be closed to isolate the hot water system (say, for a quick trip in the winter) where you want to keep water out of the hot water heater and hot water pipes. The second valve is normally closed but can be opened to drain the hot water out of the water heater through the heater's intake fitting and back into the main tank. Pretty slick. There are pictures of all this on the FWC web site in the current version of the FWC manual.

The only difference with my 2009 Hawk is that the second valve described above doesn't drain the heater back into the main tank, it just runs into a clear plastic hose that I have to put in a bucket to catch the hot water draining out of the hot water tank. I can do that.

One thing to remember when draining the water heater is that you have to open a hot water faucet so air will flow backwards into the water heater outlet when the water is draining back out of the heater. Otherwise, there'll be a vacuum created in the top of the hot water tank that will make it harder for the water to drain out. Guess how I learned that lesson!

By the way, I'm starting another thread about the hot water heater with links to the manual. The link on the FWC service manuals web site page is wrong and goes to an entirely different Atwood heater than the one FWC uses. The manual has useful information about winterizing and flushing the hot water heater.