# Filling Hot Water Tank



## WOODTRAILMAN (Nov 6, 2003)

Hey Outbackers
Make sure yall open the pressure relief when filling the hot water tank. I did'nt open it and the air blew out the drain plug. Bounced off the cement driveway and landed about 200 feet across the yard. lucky no one was in the path of this flying plastic projectile. Funny thing though, it did'nt strip out the threads on the plug.
Be careful, Wood


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## NDJollyMon (Aug 22, 2003)

Good point!


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## MaeJae (May 12, 2005)

Kinda sound like the Champagne incident???? Eh, Rob?

OK this will be the last time I razz you about it.









Maybe.


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## Katrina (Dec 16, 2004)

a good tip.
Another good tip is to keep a spare drain plug on hand.
You DO have a spare drain plug, don't you?


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## MaeJae (May 12, 2005)

NO?
I don't have a spare plug... I really need a spare plug?...
OMG... I better get a spare plug.

OK, now I'm freking out!


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## Lady Di (Oct 28, 2005)

Didn't know anything about that being a possibility. We do, however usually open the relief valve to be sure the tank is full.


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## Rubrhammer (Nov 27, 2006)

I generalyrun some water in the fresh water tank and thenopen a faucet to purge lines. I do this before each trip because I drain everything after each trip. After the lines are purged I flip the breaker back on for the water heater. That way I don't have to worry about forgetting to do it when I get to the campground. Used to be I'd have to hear "why isn't there any hot water" before the breaker would get turned on. LOL
Who says men can't be trained?


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## N7OQ (Jun 10, 2006)

Gee maybe you could put a potato in the drain and aim it at your neighbor


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## Ohtrouting (May 27, 2006)

WOW!







I'm glad no one was hurt.


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## DaveRL (Feb 26, 2004)

One point seems to have been missed here. A water heater is designed to use city water presser or pump presser. Unless the system was being filled under extremely high presser or the plug was bad, there is no way it would have popped.







There shouldnâ€™t be a need to vent the tank unless you want to fill it faster.


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## bentpixel (Sep 2, 2006)

Sound like a pressure regulator would help. My Atwood heater needs an air gap.

Here is a link to the user guide.

Glad noone got hurt.

Good Luck,
Scott


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## outbackj (Oct 31, 2006)

This is an old topic. I am glad someone brought it back to life though. What in the heck are you guys talking about? I have never opened anything on my water heater before filling. Not in the trailer, or my house. I have never had a problem. Now however, I, and along with a million other campers are probably nervous about this coming year. And whether or not to even use the water heater. Please explain this experience you have had. Was it just one person, one time? Does it happen on a regular basis? Is it going to happen to me? And remember everyone put those stem caps back on after filling tires with air.

Jm


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## Lmbevard (Mar 18, 2006)

the recommended procedure is to open a hot water faucet while filling the hot water heater, whether in the RV or in the house. You may or may not have to pop open the pressure relieve valve on the RV hot water heater, it is recommended to do so to be able to use the whole capacity of the tank, but you do not have to remove all of the air from the top of the tank.

As far as blowing the plug, this is not something that happens all of the time, there had to have been something different for it to blow like this. Check the plug before installing to see if there is any damage to the threads, make sure it fits tight and is not cross threaded. Others have replaced the plug with a brass plug because the plastic plugs are easily messed up.

As far as this happening, I don't think it happens often, but obviously it can happen.


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## watervalleykampers (Jan 16, 2007)

Good to know. DH usually takes care of that kind of thing, and I think he turns on the hot water tap when filling the tank.


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## 2500Ram (Oct 30, 2005)

Lmbevard said:


> Others have replaced the plug with a brass plug because the plastic plugs are easily messed up.
> 
> As far as this happening, I don't think it happens often, but obviously it can happen.


I've been told the brass plug is a big NO NO with a ceramic lined heater like the OB's have. (I think it's ceramic, some type of glass) The main time the plug blows is when you drain the tank not filling. Opening the pressure relief valve is recommended before pulling the plastic plug.

Good luck
Bill.


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## SouthLa26RS (Jul 10, 2006)

Would a drain plug that is in good condition and properly installed blowout, before the relief valve itself would relieve? Was the hot water heater already on before the water was introduced into the system?


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## CamperAndy (Aug 26, 2004)

2500Ram said:


> Others have replaced the plug with a brass plug because the plastic plugs are easily messed up.
> 
> As far as this happening, I don't think it happens often, but obviously it can happen.


I've been told the brass plug is a big NO NO with a ceramic lined heater like the OB's have. (I think it's ceramic, some type of glass) The main time the plug blows is when you drain the tank not filling. Opening the pressure relief valve is recommended before pulling the plastic plug.

Good luck
Bill.
[/quote]

The water heaters in the Outback trailers are all aluminum with no lining. They use plastic plugs because the aluminum is soft and would easily distort when a brass plug was used. You can still use a brass plug, just don't crank down on it when you install it,

As for the plastic plug blowing out, I will give a possible reason. If the tank were heated with propane and no water in the tank then the plug could actually soften/melt to the point that the normal pressure developed while heating the tank could have blown it out.


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## Oregon_Camper (Sep 13, 2004)

Funny...

2 posts to this thread when it was posted in 2004.

Counting my post, it has 16 new replies.

Are we all bored and a bit stir crazy for spring to arrive?


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## Scott and Jamie (Aug 27, 2006)

CamperAndy said:


> The water heaters in the Outback trailers are all aluminum with no lining. They use plastic plugs because the aluminum is soft and would easily distort when a brass plug was used. You can still use a brass plug, just don't crank down on it when you install it,


Only use a plastic plug!! Aluminum will react with other metals and it is usually the loser! Using a brass plug can slowly eat your tank from the inside out. Use the plastic plug and replace it everytime it is removed. It will cost you alot less in the long run.


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## Txcamper (Apr 3, 2006)

Good safety tips!


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## 2500Ram (Oct 30, 2005)

Scott and Jamie said:


> The water heaters in the Outback trailers are all aluminum with no lining. They use plastic plugs because the aluminum is soft and would easily distort when a brass plug was used. You can still use a brass plug, just don't crank down on it when you install it,


Only use a plastic plug!! Aluminum will react with other metals and it is usually the loser! Using a brass plug can slowly eat your tank from the inside out. Use the plastic plug and replace it everytime it is removed. It will cost you alot less in the long run.
[/quote]

Sorry for the mis information I gave earlier. I was under the impression it had some glass liner, but either way, it was not recommended to use a brass plug.

Happy hot water everyone.

Bill.


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## CamperAndy (Aug 26, 2004)

Scott and Jamie said:


> The water heaters in the Outback trailers are all aluminum with no lining. They use plastic plugs because the aluminum is soft and would easily distort when a brass plug was used. You can still use a brass plug, just don't crank down on it when you install it,


Only use a plastic plug!! Aluminum will react with other metals and it is usually the loser! Using a brass plug can slowly eat your tank from the inside out. Use the plastic plug and replace it everytime it is removed. It will cost you alot less in the long run.
[/quote]

I would agree with the statement if a steel or iron plug was used but brass is close enough to aluminum on the Nobel scale to not be an issue. The main reactive metals for any electrolysis is in the iron content of the water itself. Notice that the relief valve and the inlet and outlet check valves that are installed in the tank are brass fittings.


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## j1mfrog (Jun 6, 2004)

CamperAndy said:


> The water heaters in the Outback trailers are all aluminum with no lining. They use plastic plugs because the aluminum is soft and would easily distort when a brass plug was used. You can still use a brass plug, just don't crank down on it when you install it,


Only use a plastic plug!! Aluminum will react with other metals and it is usually the loser! Using a brass plug can slowly eat your tank from the inside out. Use the plastic plug and replace it everytime it is removed. It will cost you alot less in the long run.
[/quote]

I would agree with the statement if a steel or iron plug was used but brass is close enough to aluminum on the Nobel scale to not be an issue. The main reactive metals for any electrolysis is in the iron content of the water itself. Notice that the relief valve and the inlet and outlet check valves that are installed in the tank are brass fittings.
[/quote]

Right, I was just about to say the same thing, the Nobel scale, yeah that's it.


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## Scott and Jamie (Aug 27, 2006)

Aluminum is a very soft metal and brass is a much harder metal. Installing a brass plug once can cause damage. And yes the the combonation will react after a period of time. The preassure relief has been coated with a inhibator before it was installed to keep the threaded metal from reacting to each other. Using a brass plug will very quickley wear out the threads on the aluminum taken. As the threads get "looser" the two metals will slowly start to react inside the gaps between the brass and aluminum threads were water is stagnate. The worst is you can strip the threads or enlarge them by over tightening even with the first time using a brass plug.

scott


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## CamperAndy (Aug 26, 2004)

Scott - I guess we agree on some things but I have to disagree on a few others.

The first time I mentioned the use of a brass plug I said it can distort the drain IF you make it too tight. If you put it in properly you can do it a 100 times and still not damage the tank. That said you could wear out a 1000 plastic plugs and not damage the tank. I use plastic but if I had a brass plug which I would take out once a year, I would go a hundred years before anything would happen because of it being brass and by then I would have other things to worry about.

As for any isolation between the relief valve or the check valve and the tank, there is none. Any pipe dope or tape that is used, is used solely for the purposes of sealing it from water leak and has zero effect on isolation of the 2 metals to prevent electrolysis.


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## renegade21rs (Oct 8, 2006)

Oregon_Camper said:


> Funny...
> 
> 2 posts to this thread when it was posted in 2004.
> 
> ...


























YES !!!


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## GarethsDad (Apr 4, 2007)

Sorry to say but I'm a Plumber and thread tape or pipe dope are used as a lubricant to get the fittings tighter than you could without using them. Brass and Aluminum are both non ferrous metals and your tt would be retired by the time that enough damage was done by the corrosion unless your using well water with lots of trace minerals or city water with high levels of chlorine. Most T&P or tempetature and pressure relief valves are set to fail at 210 degrees before the water boils and turns to steam. On the pressure side it will let go before the max pressure for the tt water system. Just my .02


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