2012 Water Leaks Update

[mtntime]

When I spoke with the factory last week about the water leaks due to over pressurization from the hot water tank heating. As Doug stated the air bubble must be maintained. According to the factory the air bubble dissipates over time and must be renewed. Again as Doug stated this should probably be done prior to each hookup and perhaps once a week or more if extended stay.

I asked the factory if this was in the Airstream owners manual and was told no but he thought it was in the Atwood manual. I took a look and on page 5 at the bottom it goes through the steps just as Doug outlined.

HOWEVER per the Atwood manual page 5 second column at the top it states for a permanent solution, we recommend one of the following:

1) Install a pressure relief valve in the cold water inlet line to water heater and attach a drain line from valve to outside of coach. This was one of my suggestions.
2) Install a diaphragm-type expansion tank in the cold water inlet line. This was suggested by Bigventure.

A premium travel trailer product should have one of the two permanent solutions installed.

I would imagine that this could be causing a lot of the leaking issues. I for one have never done the “renew the air bubble routine” in 20 years of trailering. Perhaps my other trailers had expansion tanks. The explanation and instructions for maintaining the air bubble should be covered in the Airstream manual in BOLD as well as the delivery walk through.

Given my water leaks and desire for a permanent solution I decided to go ahead (it was on my list) and install a Precision Temp RV-500 instant hot water heater. This completely eliminates the hot water over pressurization problem, provides a much easier winterization (no tank to drain) and an endless supply of hot water for showering.

Is the RV-500 an option that can be ordered on new trailers?

Just like "putting the jacks down" everyone should refresh the air bubble each outing or often if extended stays. This just might help the plumbing last longer since there is no other protection provided by Airstream.

[SilverRanger]

"I for one have never done the “renew the air bubble routine” in 20 years of trailering.'

Same here. Never had to do it, or even heard of it, until your problem. Thanks for reporting back.

[knunut]

Looks like it takes up the same amount of space . Did it require any extensive "replumbing"?
Never heard of the bubble problem,but i like the solution.

[dkottum]

Doug here. I never had the "bubble" problem until I got the 2012 trailer with the combo electric/propane hot water heater and went on extended trips with it. The combo heaters apparently stay hotter than the earlier gas-only models, absorbing the air bubble sooner. A fifth-wheel full-timer filled me in on it, easy to open the relief valve and renew it now and then when you're out for long trips.

doug k

[Wayne&Sam]

Huh? Why wouldn't the over pressure valve on the hot water tank take care of this?

[danlehosky]

After 30 years in the business and a PE in mechanical engineering I can tell all of you this system should have a small expansion tank. The small diameter piping and the short runs are not able to withstand the pressure from the heated water. I'm not going to go into the math but AS missed the boat on this one. Howard, for a simple (fix) after the tank heats up, open a faucet for a few seconds. This will relieve the excess pressure. THIS IS POOR DESIGN AND EXECUTION. Maintaining an expansion bubble in the tank is ridiculous. It also cuts down on hot water capacity. And for what it's worth, mine has leaked ubder the sink at the filter and at the TP valve on the HW tank.

I'm going to install a small expansion tank in the bottom of the bedroom wardrobe where the access to the by-pass is located.

Adios,
Dan

[danlehosky]

Doug, opening the TP valve will not create an air bubble. In fact opening it will elimanate any air pockets in the water heater. It's a high point.

Dan

[mtntime]

It was a bigger project than I expected, but what isn’t, and I should do a separate installation thread for those interested. I had a nice conversation with Precision Temp this morning regarding the installation.

The trailer water pressure input is limited to 65psi and the hot water pressure relief valve is 125psi. 125psi is double the input rating and puts a lot of stress on the lines causing the leaks.

Doug is right when talking to the Airstream tech support I was told that the new Atwood 6 gallon was equivalent to a 10 gallon unit because it heats the water to a higher temperature. I would assume electric or gas use would be the same temp.

The top of the tank is higher than the relief valve. Here are the instructions to replace the air gap from the Atwood manual.

1. Turn off main water supply or pump.
2. Let water cool or let run till cool.
3. Open the hot water faucet closest to the water heater.
4. Pull handle of pressure temperature relief valve straight out and allow water to flow until it stops.
5. Allow pressure temperature relief valve to snap shut; close faucet; turn on water supply.
6. Turn on water heater and test.

Like the new ATS switch the “improved” higher temperature hot water tank might be a good idea but it is executed very poorly by the factory.

I cannot stress enough that everyone should follow the “replace air gap” procedure often or there is going to be future water leaks guaranteed. Unless you are going to be very diligent about opening the faucet ANY AND EVERY TIME the hot water tank is heating it is going to put stress on the water lines.

This is another issue that I am adamant the factory should correct by adding a secondary bypass valve rated at say 75psi to make damn sure the trailer is not potentially damaged due to the hot water tank over pressurizing the water lines. The nice thing about the secondary bypass valve is that it would protect the system in case of extremely high shore water pressure/surge or a failure of the built in 65psi regulator. The next best solution would be the diaphragm-type expansion tank. Prior to deciding to put the RV-500 in I was planning on installing a hot water 75psi pressure valve as commonly used in hot tubs at the hot water heater draining out of the trailer. It is cheap and would be easy to put in.

Why should we be upgrading the ATS and/or installing over pressurization protection devices in our new Airstreams?

[bycrom]

This is the thread I have been looking for, it ought to test something I was told by AS, as noted in thread 40 of my post "Quality of new... sigh...".

I am in complete agreement that this is a design flaw, in fact I just ran this by a hydronic heating expert who was shocked there was no expansion mechanism in place.

I want to see if Dan was correct when he stated they have a process in place to fix design flaws. I will be calling Dan (who reads this forum) and pointing him to this thread for comments if this issue will be address mid-year stream. e.g. 2013 should incorporate a fix for this if everything he said was in place.

I will keep this thread (and my original thread) up to date with what I find.

[dkottum]

bycrom, there is an expansion mechanism in place and that is the air chamber in the water heater itself. Over time that can be absorbed by the water. So that is the design by Atwood water heaters. Contact them.

The design has worked for us in six months use, not so for Collimare. I have to admit having some tolerance for a less than perfect world, and enjoying the heck out of our Airstream, our under-powered truck, lousy roads our lousy government makes us drive on, and rainy days.

doug k

[mtntime]

Originally Posted by dkottum

bycrom, there is an expansion mechanism in place and that is the air chamber in the water heater itself. Over time that can be absorbed by the water. So that is the design by Atwood water heaters. Contact them.

The design has worked for us in six months use, not so for Collimare. I have to admit having some tolerance for a less than perfect world, and enjoying the heck out of our Airstream, our under-powered truck, lousy roads our lousy government makes us drive on, and rainy days.

doug k

Here we go again, this is not an Atwood design issue at all, it was a decision made by the Airstream engineers/factory to rely on the air chamber as the sole protection in the system. If you look at the excerpt (below) taken directly from the Atwood manual it states how to DESIGN the system to insure over pressurization does not occur. It is a 25$ solution that Airstream decided not to include, plain and simple!

If you are not happy about needing to constantly restore the air chamber than contact Airstream to install the correct solution, not Atwood, or as I did and others have suggested, install a solution yourself.

[danlehosky]

Everybody, I enjoy my AS very much and expect the normal maintenance that these very special trailers warrant.

This waterheater issue is dangerous though. Most people don't have the experience or the knowledge to regulate an air chamber in a 6 gal waterheater. You can't visually observe the chamber and the short runs and small diameter of the piuping leaves little room for expansion. An expansion tank in this situation would give you the assurance of having a system that would function correctly instead of depending on an unsen air bubble. To install this system with the expectation that people would be able to maintain the pressure was a poor decision.

When designing closed loop hot water systems, expansion should be your first consideration. As cold water heats it expands and needs someplace to go. Depending on a bubble in this case with so little piping is not a good idea.

I was sitting in my trailer one day and saw water coming out from under the sink. I opened the door and discovered that the connection to the filter body had sprung a leak. When I went outside to shut off the water I discovered a puddle underneath the waterheater and the temperature and pressure relief valve was leaking..... As it should have been... Thats what it's designed for.

To install a system that so easily leaks and expreses itself through a safety device is just plain bad engineering. No ifs and or buts.

I'm not sure what temperature the waterheater is capable of reaching but anything over 120 degrees is dangerous and in certian jurisdictions exceeding this temp is unlawful.

I like my AS very much and plan on keeping it for many years. I hope the factory recognizes this problem, makes the fix retroactive and incorporates the addition of a properly sized expansion tank into it's production procedures immediately.

Adios,
Dan

[lewster]

Allow me to add a little 'fuel to the fire' so to speak.

If the newer Airstreams use the Atwood XT series of water heaters (10 gallons of hot water from a 6 gallon tank) they do indeed run at about 20* hotter with a special thermostat. This puts the tank water at between 150-160*F, which is far above the recommended faucet temp. of 120*F. To bring the faucet temps down to the non-danger zone, Atwood units employ a mixer valve that lets cold water into the hot water stream to temper the hot water coming directly from the tank.

If you look further into your Atwood manual, you will see a section on 'mixing valve maintenance'. They state that this mixing valve should be cleaned at a recommended interval with , IIRC, vinegar to remove the accumulation of calcium and other minerals from the fresh water supply. From what I have seen, almost no one actually does this and the result is a clogged mixer valve that now must be replaced. You will tell if you have this situation when your water heater still seems to operate properly and the tank gets hot and hot (very hot) water will come out of the relief valve if tripped, but you get no hot water, or increasingly cool to cold water from the faucets. The mixing valve is now allowing the cold water to pass thru, but the hot water chamber has been compromised and is clogged.

Time to replace this very expensive (over $200) valve. I have replaced over 20 to date, mostly on larger motor homes............have fun! YMMV!

[mtntime]

Originally Posted by danlehosky

I hope the factory recognizes this problem, makes the fix retroactive and incorporates the addition of a properly sized expansion tank into it's production procedures immediately.

Adios,
Dan

The response I got from the customer service representatives that I spoke with last week about the water leaks due to the hot water tank over pressurizing the lines and my putting in the RV-500 to fix it was “there is no problem as the Airstream water system is designed to handle the additional pressure and tested to 150psi”. If this is true why limit the incoming pressure to 65psi? Why have some of us had leaks?

From my discussion with AS, AS does not consider this an issue!

Brycom please let us know what Dan says about the problem.

[mtntime]

Originally Posted by lewster

Allow me to add a little 'fuel to the fire' so to speak.

If the newer Airstreams use the Atwood XT series of water heaters (10 gallons of hot water from a 6 gallon tank) they do indeed run at about 20* hotter with a special thermostat. This puts the tank water at between 150-160*F, which is far above the recommended faucet temp. of 120*F. To bring the faucet temps down to the non-danger zone, Atwood units employ a mixer valve that lets cold water into the hot water stream to temper the hot water coming directly from the tank.

If you look further into your Atwood manual, you will see a section on 'mixing valve maintenance'. They state that this mixing valve should be cleaned at a recommended interval with , IIRC, vinegar to remove the accumulation of calcium and other minerals from the fresh water supply. From what I have seen, almost no one actually does this and the result is a clogged mixer valve that now must be replaced. You will tell if you have this situation when your water heater still seems to operate properly and the tank gets hot and hot (very hot) water will come out of the relief valve if tripped, but you get no hot water, or increasingly cool to cold water from the faucets. The mixing valve is now allowing the cold water to pass thru, but the hot water chamber has been compromised and is clogged.

Time to replace this very expensive (over $200) valve. I have replaced over 20 to date, mostly on larger motor homes............have fun! YMMV!

Thanks for the info Lew! You are always on top of things!!

WOW!! Really 160 degrees?? No wonder it is causing expansion over pressurization problems. Is the air chamber new for the XT series to compensate where it was really not needed before or just much more critical to maintain now?

Sounds like AS just put the newer XT model in without full consideration/engineering to the increased stress on the system.

Glad I replaced mine already!!!

[xrvr]

If normal maintenance is cleaning the mixing valve, then why not just keep the valve clean. Have I missed something here? Just put this on your normal mantenance schedule. If I am correct if the valve is kept clean it does not have to be replaced. Jim

[lewster]

Originally Posted by zigzagguzzi

If normal maintenance is cleaning the mixing valve, then why not just keep the valve clean. Have I missed something here? Just put this on your normal mantenance schedule. If I am correct if the valve is kept clean it does not have to be replaced. Jim

Unfortunately, the 'normal maintenance' is anything but normal.

In order to clean the valve with vinegar you have 2 choices:

1. remove the valve from the water heater, soak in vinegar, rinse, repeat until clean and the re-install......( might not sound like such a big deal, but try a few and get back to me on that one)

2. Drain the water tank, fill with vinegar (yes, all 6 gallons of it), pressurize the tank (how you do it is up to you), run the vinegar thru the hot only faucet
so that all of the vinegar flows exclusively thru the hot side of the mixing valve until the tank is empty, fill and flush several times with fresh water until any trace of vinegar is removed ( unless of course you eat a lot of salads, then leave it and just add oil for a nice, healthy salad dressing )

Take your pick!

OH! I forgot option 3..........

3. Wait for the unit to fail and simply replace the valve................

[xrvr]

More involved than I thought, thanks. Jim

[crisen]

I had been looking at owners manual on line in preparation to pick up our new trailer as well as following this hot water heater thread. Here is quote from the owners manual. It sounds like they are aware of the issue but don't recongize the severity of the problem. Has anyone had this water leak problem when not connected to city water, i.e. using the 12v dc water pump?

Thanks, Rick

If your water system is full and cold and the water heater is ignited the system can see pressures as high as 120 psi before the relief valve starts to open. Since the water system normally operates in the 40-psi range the water expanding does put unusual stress on the system. This normally does not cause any problems, but the stress is easily alleviated. As the water is heating just open any faucet and run as little as a cup of water. Just removing this small amount of water reduces the pressure build up significantly.

[mtntime]

Originally Posted by crisen

I had been looking at owners manual on line in preparation to pick up our new trailer as well as following this hot water heater thread. Here is quote from the owners manual. It sounds like they are aware of the issue but don't recongize the severity of the problem. Has anyone had this water leak problem when not connected to city water, i.e. using the 12v dc water pump?

Thanks, Rick

If your water system is full and cold and the water heater is ignited the system can see pressures as high as 120 psi before the relief valve starts to open. Since the water system normally operates in the 40-psi range the water expanding does put unusual stress on the system. This normally does not cause any problems, but the stress is easily alleviated. As the water is heating just open any faucet and run as little as a cup of water. Just removing this small amount of water reduces the pressure build up significantly.

I cannot address the question directly from experience as I only run the pump to winterize. It has been noted that the lines are fairly small and even if pressurized with the pump and there is no air cushion in the hot water tank I would think it would over pressurize the system in just the same manner.

I would like to point out that the referenced statement in the 2012 manual Appliances/Water Heater/Safety is the same statement going back to at least the 2002 Classic Trailer. It does not take into account the new higher temperature Atwood XT water heater currently being used in the new units nor does it reference the requirement to maintain the air cushion in the water heater per the manufactures instructions.

Airstream clearly states that over pressurization from the old lower temperature hot water heater is a potential problem going way back and leaves sole responsibility of preventing damage to the water lines up to the owner instead of installing the separate lower rated pressure relief valve in the cold water line or the expansion tank in the cold water line as recommended by the manufacture of the hot water tank.

Just wondering how many water leaks might have been prevented with a simple $25 pressure relief valve over the years.