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Old 01-07-2020, 06:07 AM   #1
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Hot water from cold faucet

Hi everyone and happy new year!
First time I've seen this, I'm getting hot water from all the cold faucets and only a trickle from the hot faucet. The bypass valve at the water heater is in the same position it was in all year and the inside and outside shower faucets are closed.

Yesterday, I removed the check valve at the water heater to find it clean. I did this because I had to clean the aerators of sediment buildup.

The one thing I can think of that may have contributed to this problem is that I blew air into the system a few weeks ago when the temperature had dropped into the 20's.

Any thoughts?
Thanks,
Rich
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Old 01-07-2020, 05:18 PM   #2
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Hi Rich,

Here is a "maybe".

Since you are only getting a trickle on the hot water side, that points to the check valve on the top of the water heater having it's plunger keeper fall off. (it fell inside the tank) When this happens and there is no keeper on the check valve stem, the plunger and spring flies off into the elbow fitting downstream of the check valve and plugs the hot water pipe from passing water to the faucets. This has happened before.

See this post with pics from BenB when the above happened on his heater.
http://www.sunlineclub.com/forums/f7...low-17598.html

The above explains one way you can get the hot water trickle on the hot side.

To getting hot water in "all" the cold faucets, I have a possible way, but a few things have to line up to make it happen, and I need to ask some questions first. First some pics of what I "believe" your T2499 looks like. These pics are from my 2007 T2499 project camper. My 2004 T2499 from years back looked the same. Unless a former owner changed yours, they should look the same.







Does your look like those pics?

Assuming yes, a few questions,

1. The bypass lever valve on the bottom blue line, please confirm that the lever is pointing horizontal and not vertical? Make sure it is not part way between horiz and vertical or some part thereof. I know you said it has been the same way all year, but please check and report back. If it is not 100% rotated down horizontal, the valve can still allow flow from the bypass.

2. Are you on city water or the fresh tank and water pump when this happened?

3. Do you leave the water heater turned on all the time while you are in the camper? If so, on gas or electric? If you do not leave it on all the time, how long was the heater on before you noticed hot water made it to the cold faucets?

4. When you said hot water flows from all faucets, about how long did you run the cold water to feel the hot coming out? Think in seconds.

5. Did the hot water trickle issue start before or after you blew out the camper with compressed air?

6. You mentioned you compressed air blew out the camper, explain the process you did to get air into the lines and what did you do to "burp" or allow water to be blown out. The reason for asking this method you did is, I know of one way on how the check valve can come apart when using the compress air blow out method.

7. What process did you do to clean the water heater check valve?

Hope this helps

John
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Old 01-07-2020, 06:28 PM   #3
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Hi John,
Thanks for the reply with photos!
My setup looks just like your photos.
1-The bypass lever is horizontal as in your photos.

2-I was on city water, but I tried it on the pump and it did the same thing.

3-water heater was on electric all the time.

4-hot water began to show up about 5-10 seconds after turning on the faucet.

5-Both problems began at the same time as soon as we set up this weekend which was a few weeks after I blew the water out with air.

6-I used a screw in adapter to the city water supply with the faucets open (and the low point drains).

7-the plastic valve plunger was pretty clean and I used a wire brush on the outside (threads) and. A spiral paint gun brush for the inside.

You mentioned a spring, but I didn't see a spring inside the check valve, just a plastic (nylon?) Plunger with an o ring.

Tonight, I disconnected the hot water line at the kitchen faucet and at the check valve and blew air through it. No obstruction there.
Rich
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Old 01-07-2020, 11:32 PM   #4
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Rich,

I think your main issue is, the check valve on the top of the water heater came apart. The plunger keeper fell off and is laying inside your tank, most likely never to be removed. They have fell off sometimes just by working normally. It is not a robust valve. The plunger is then loose to come out and blocks normal flow out of the top of the water heater. That is the hot water faucet restriction.

This is what the plunger looks like out of the valve.


The plastic keeper looks like this. The only way to see the keeper with the check valve on the tank, is to take the entire brass check out of the tank and look from the inside.


The keeper press fits onto the check valve stem to get past a finger holding arrangement to get on. Those finger grips, ridges actually on the stem, get worn or weak and the keeper flys off. If you cleaned yours and the entire white stem and Oring were out in the open with you, for sure the keeper flew off in the tank. The white stem will not come out the top if the keeper is still on.

This past winter I was blowing out a water heater for a friend I was helping him with his camper. During that blow out, the keeper popped off. It bobbled around one too many times during a low point drain burp, and the keeper flew off. To fix it , I took the plunger out and didn't use it. Then installed a second bypass valve at the top in place of the Tee that is there. BenB's post I liked did this. Converted it to a 2 valve bypass setup.

If you are out camping and want to do a quick patch, let the heater cool down, drain off all pressure in the system and remove the plastic valve stem which should be loose in the check valve. Then put it back together. The check valve is only there to make the winterizing bypass work. Granted you no longer have the bypass, but your out camping and can deal with fixing it when you get home.

Now how the hot water made it to the faucets. I'm creating this "how it happened" from theory and testing on water heaters I have done. I have also seen this happen on here on SOC when the water heater is left on all day long. There is post on it, I can't recall who it was. I think maybe Thomascine had it happen. Just hers was not a T2499 but had a similar piping setup.

The water heater when it heats water, the water expands and that expansion creates excess pressure if the air pocket in the top of the heater is dissolved. Which that air pocket will in time dissolve given the right situation. There are no bladder expansion tanks as OEM from Sunline or most other camper manufacturers to stop this pressure build. From my testing, the pressure in the water heater can rise from 50 psi reach 120 psi with just one heating cycle. It will go even higher with little to no air pocket.

Since you are on city water, on the T2499 the city water piping is in the same pic as the water heater. The incoming cold water goes right past the hot water heater in route to all the faucets.

In your case, if the water heater is heated and the pressure at 100psi at the heater and above, when you turn on the cold water faucet, hot water will come out of the heater and mix with the incoming cold on the way to the cold water faucet. The excess water pressure in the heater tank will allow hot water to come out the bottom inlet into the cold line backwards. If you let the faucet run long enough, the excess pressure in the heater will drop to the same pressure as the incoming cold water and stop backing out hot water. It might take a minute or so to drop the pressure so you are going to get a good slug of hot before cold comes.

To stop the hot water backing out of the heater issue, rebuilding the air pocket in the heater will help as a first step. Drain about a gallon of water out of the heater, open the safety relief valve to let air go back in, close the relief valve, then pressurize the system back up. The air pocket will stay in the top until the next time it dissolves.

Since you have both gas and electric on/off controls in the camper with the flip of a switch, turn the water heater off when you are done using hot water. Turn it back on about 30 minutes before you start using it and the ultra high pressure build will stop. OR install an air bladder accumulator if you want to leave the hot water on all day long.

I never leave the hot water on all the time. We get in the habit of turning it on and off and if we forget to turn it on, we use both gas and electric at the same time to make it a little faster reheat. I do this to help stop the heavy scale buildup in the tank from hard campground water. We only use hot water about 2 hours a day. It is building scale the other 22 hours of the day.

Hope this helps and let us know how you make out.

John
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Old 01-08-2020, 06:22 AM   #5
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John, as usual, you nailed it thank you!
It's amazing to me that one can be totally baffled about a situation, but then smack themselves in the head once the solution is explained to them. It makes perfect sense now, that the plunger will act as a seal against the pipe connection washer when the hot water pushes it out unless there is something holding it away from washer like that retaining clip.
I guess the only thing to do now is buy a new check valve, do you know of a better quality valve? Home depot or rv supply?

Thanks also for the tips for good maintenance, I always just turned the water on when we set up on Friday night and left it on until we packed up on Sunday.

Rich
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Old 01-08-2020, 10:25 PM   #6
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Quote:
Originally Posted by JohnB View Post
Now how the hot water made it to the faucets. I'm creating this "how it happened" from theory and testing on water heaters I have done. I have also seen this happen on here on SOC when the water heater is left on all day long. There is post on it, I can't recall who it was. I think maybe Thomascine had it happen. Just hers was not a T2499 but had a similar piping setup.
John
Yep, it is still a problem for me. I have tried recommendations other than turning the tank off. I have to manually turn it off and on from outside so it is a hassle for me (I am lazy). I just get in a habit of letting the cold water run a few seconds before using it especially when I have a sewer hookup. But I will try turning off the tank when not in use, if I can remember.
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Old 01-08-2020, 10:53 PM   #7
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Rich, thanks for the good words. Most of this I have learned the hard way... and glad it can help someone else. I have always said, you learn more when something is broke, then when it works all the time.

Quote:
Originally Posted by vcrt View Post
I guess the only thing to do now is buy a new check valve, do you know of a better quality valve? Home depot or rv supply?
There are a few places that make the same style check that you have now. Flair-it makes one that may be the original one Sunline used, their PN 04914. It shows up in their full catalog on the Flair it site, but I can't find it for sale on the web.

PDF Page 15, bottom right corner. (catalog page 13)
http://leggettsupply.wpengine.com/wp...022218-web.pdf


Valterra makes one too. https://www.amazon.com/Valterra-P234...8544346&sr=8-3

And Aqua-pro https://www.rvupgradestore.com/Aqua-...-p/10-0702.htm

They may all be made at the same factory and private labeled. I'm not totally sure, but they all interchange. I can't say anyone of them is better than the other. The design is the issue and they all use the same design. Yes it works, but it also has been known to fail in time.

I have stopped using them. After BenB's failed and the ones I had, I gave up on the concept and now convert all my project campers to the 2 valve bypass setup as I go through the camper.

You pull the plunger out of the old check and leave it out. The brass fitting is then just a pipe nipple.

Then I take the Flair-it tee out and put a Flair-it 3 way bypass valve in place of the tee and move on. You just have to remember it is a 2 valve system and to flip both valves to bypass. Along with, when you sanitize, you open the bypass and sanitize the riser pipe, then rinse it also. And make sure you open them to drain the rise pipe when air blow winterizing.

Here is the 3 way valve. You need this part number, and you have to make sure you install it right. It will fit backwards, just it will not work right backwards. Blow through it or look inside so you know which is the common port and that goes to the water heater side.


Amazon is one place to get it https://www.amazon.com/Flair-16910-P...qid=1578543055

The change out process.

Unscrew all 3 nuts on the tee. This one I did on a friends camper out in the open when we had his heater out. You can do this in place on yours.


Pull the hoses off, they are a wedge fit so they will come off hard. Then put in the new 3 way valve. Lever points downstream in the non bypass mode.


Slide the hoses fully on. Then tighten the nut and it will swedge fit the connection.

Looks like this when you are done


In place on a T2363.


Hope this helps

John
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Old 01-09-2020, 06:00 AM   #8
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Very helpful John, after reading that you have seen the check valve malfunction, I decided to convert it to the two bypass valve setup, which is what our 2470 had. They were brass btw.

I have a plastic bypass valve I never used, but it has female threads which means I'd have to add nipples all around and that would mean I'd have to be cutting the pipes to fit the new larger size. Your valve looks like a drop-in so I'll order one of those.

Thanks for all your help john!
Also, did I mention that we moved to South Carolina? We've been here since August and we're finding our camping season is a good bit longer than back in Maryland😀.
If you ever get down this way, please let me know.

Thomascine- I'm not sure I understand what's going on with your water heater, John do you know?

Rich
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Old 01-09-2020, 06:08 AM   #9
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I almost forgot, how tight should these connections be? Hand tight like a garden hose?
Thanks,
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Old 01-09-2020, 10:38 AM   #10
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Quote:
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Thomascine- I'm not sure I understand what's going on with your water heater, John do you know?
Rich
I am also getting hot water from the cold water faucets. I already have the two bypass valve system so I am good there, new last year. Still getting hot water. Just never figured out why, both at the kitchen sink and in the bathroom. I will follow to see what you come up with. I have a manual heater that I have to light the pilot with a lighter so turning the water heater off and on is not really convenient for me.
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Old 01-09-2020, 04:03 PM   #11
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Quote:
Originally Posted by vcrt View Post
I almost forgot, how tight should these connections be? Hand tight like a garden hose?
Thanks,
Rich
I have not seen a Flait-it written document on how, tight, tight is. And I just searched their site again and can't find anything. But I can explain how I do it.

The first time you screw the nut on new fresh cut tube, the amount of tension on the nut is more then doing it a second time. The nut does cut small fine threads in the OD of the tube. You can see them in this pic on taking the old tee out.



You want the nut tight enough to cover all the threads on the fitting you are screwing it onto. I have never stripped a nut tightening them. The nuts are made very well. Once you get the nut to cover over all the exposed threads, you are just about there as far as it goes on. But it can still take little more, but soon the nut will start hitting the fitting.

They are way tighter than a garden hose with a seal rubber in them. You can use normal set of water pump (channel lock) pliers, just try and not rasp the nut. And if you do slip, the nut is buggered a little, but still very usable. They are very good quality plastic.

They do sell a tool, I bought one as I do enough of this to justify the $10 for it. It helps in tight spaces and it does not slip as it engages in the groves.





It is a very good system and they are still all made in the USA!
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Old 01-09-2020, 06:54 PM   #12
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Quote:
Originally Posted by vcrt View Post
Thomascine- I'm not sure I understand what's going on with your water heater, John do you know?

Rich
Rich,

Thomascine's and your problem with hot water in the cold faucet comes from the same condition going on in the water heater. Just in your case, your plumbing lines are much longer, that may alter how fast and how hot the water is and when it shows up at the cold faucet. And, I'm sure there are differences in how many times a faucet opens, toilet flushes in her camper, verses yours with Barbara and you using the camper. Opening a faucet, etc, bleeds down the excess pressure which helps ward off the problem.

I'm actually surprised you haven't noticed this earlier, as you have had the T2499 a while now. When you read what I'm going to explain, maybe you can see some differences in your last trip. Or a trend starting to form.

Here is what is going on.

As I said above, when water is heated in a closed system, thermal water expansion occurs and pressure builds if not accounted for. The hotter the water, the more the expansion and pressure. This happens on every RV water heater when the water is heated. This is nothing new, just you may never thought much about it.

When the heated water cools, the expansion is relieved and the pressure decreases. How high the pressure gets, has several variables to it.

We know the safety relief valve will trip when the water reaches close to 150psi Or close to 210 deg F. (it is a double rated valve) so here is an upper limit. This same thermal expansion issue commonly causes, weeping of water from the safety relief valve. You may have seen this, as water drips outside of the heater cover. The pressure approaches the 150 psi area for the weep to happen.

I did some tests on this last year with a pressure gage screwed into the drain port on the water heater, the starting water pressure in the system was 65 psi and 60F fresh cold well water in the system. Turned the heater on gas, and let is run until it shut down. It took 55 minutes to heat it to the point the burner shut off. The hot water temp was 142F at the kitchen sink hot faucet after a purge. The pressure before opening the faucet was 122 psi.

End result, 55 minutes of gas burner running to raise 60F water to 142 F. Pressure rose from 65 to 122psi or 57psi. This heater had a lot of mineral scale build up in it which was part of why it took so long, that and the fact is started with cold well water, not left over warm water from the last heating cycle.

Now some of the variables that makes the pressure go higher then when the water is heated more than normal. I might have miss one or two, but these are the most common.

1. The size of the air cushion in the top of the water heater at the time of heating. This is a changing variable all the time.

2. The water temperature when you start heating the water. A subset of this variable is how long the water heater has been turned on. Colder water takes longer to heat and thus more thermal expansion pressure.

4. How much time has passed since any water was used in the camper. Open faucet, shower, toilet etc. drops the pressure down to pump or city water pressure.

5. How much scale build up is in the water heater dampening the response time of the water temp getting to the thermostat. Hard water makes this issue worse.

6. How accurate the thermostat is. It is set to 140 F from Atwood. Heavy scale affects this too as it insulates the tank from the sensor.

7. What the system water pressure is in the camper, before turning the water heater on. This system pressure is the city water inlet pressure or the on board water pump pressure sets this pressure.

Now to, how does the hot water get into the cold water faucet? It gets there from 3 ways, water thermal expansion, water thermal convection and the big one, the actual plumbing routing of the water heater "cold" feed connection to the heater in relation to the sink faucets feed. The last one, the piping can be a difference in why this issue never occurs on some folks campers who leaves the water heater on all the time. The piping is setup different due to floor plan and masks some of the problem.

I have explained the groundwork above, if you didn't understand that up until now, ask for clarification.

Next is how the hot water gets into the cold water lines when you leave the water heater on all the time on ďcertainĒ floor plans.

To aggravate the problem, the cold feed supply line to the faucets is inline and downstream of the cold feed line to the water heater. Your T2499 on city water is a perfect example of this. The city water line connects at the cold feed line junction to the water heater before it goes to the faucets. Meaning, fresh city water runs right by the water heater cold connection on the way to the faucets.

Assuming no faucets or toilet is used while the water heater heats, the hot water pressure rises due to the thermal expansion. The size of the air cushion in the heater has an effect on how high it will get. The pressure will get higher, faster if there is no air cushion.

When the heater shuts down, the pressure in the system could be in the 80psi to 120 psi range, or even higher. This is a variable that changes. Since we have a check valve in the city water inlet and in the water pump, that pressure will stay in the system until you open a faucet, toilet or until the water heater cools down lessening the expansion.

As time goes by (hours worth) and the water heater remains on, heat convection happens on the cold water line. Heat from the water inside the heater convects through the cold water inlet tubing backwards out into the cold water piping. The cold water in the pipes close to the heater then starts getting hotter than it was before. The more time goes by, the heater will kick on again reheating the water heater, more convection happens, more expansion can build, more heat goes backwards by convection into the cold water pipes. Leaving the heater on overnight and never opening a faucet or flushing the toilet, 8 to 10 hours can go by, and a fair amount of heat can move into the cold water piping.

The first time you turn on a cold faucet, the pressure in the system (could be 80psi to 120psi or higher) has to drop below the pump turn on point (approx. 35 to 40psi) OR below the incoming city water pressure (approx 50psi or greater.) before actual new fresh water enters the camper piping. Water in the heater flows being pressure pushed backwards out the cold feed pipe supply of the water heater and into the cold line until the pressure bleeds down enough that the fresh city water comes in or the pump turns on. You end up getting a slug of very hot water that is then followed by new fresh water cold.

If you flushed the toilet before turning the cold at the sink, that would bleed off a lot of the excess pressure into the toilet and you may have not noticed it. If you open the hot faucet first, you expect hot to come out and all it OK, and you bleed the pressure down in the process when you did. If you turn off the water heater, the system will cool some, the pressure build will decay and the problem lessens to totally goes away.

You have to line up the right circumstances to make getting a slug of hot water out the cold faucet, but it can happen. If you turn off the heater after using hot water, the water stays warm from the insulated tank and the excess pressure problem never builds. You have minimal thermal convection occurring as the water is cooling and thermal expansion reversing draws cold water entering the heater versus leaving it.

Do that add up now? There are some ways to help get around this, but you have to change some things to get the variables in your favor.

Thomascine's camper has the same issues, just hers has an all gas heater and no on/off switch inside making it convenient to flip the switch.

Hope this helps

John
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Old 01-11-2020, 07:20 AM   #13
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Excellent! I had no idea how many factors are at play here. My air space was probably non-existent and leaving the water heater on constantly was not doing us any good, so our habits will change.

This will be especially helpful this year as Barbara and I are planning a cross-country trip. Not sure where or how well go about it but any helpful tips are appreciated!
Thanks again john and you should probably put this as a sticky.
Rich
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Old 01-11-2020, 11:21 PM   #14
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Rich,

If you are going cross country, and like most every other RV'er, the water heater is filled from the start of the trip. The long towing, bouncing in the camper, has been known to shake up the air pocket in the top of the water heater. That shaking can and will dissolve the air pocket and then the thermal expansion issue gets worse, faster.

You can tell sometimes when the air pocket is all but about gone by 2 things normally.

1. The water heater safety relief valve drips/weeps when you are heating water. Even in only on a short time of heating. There is no place for the water to expand into so the pressure builds real quick. The Atwood manuals even talk about the air pocket being lost the the valve weeping.

2. The water pump will bang louder and faster then normal. Since it has to build pressure to shut off, the pump has to work harder to jam water into the system with no air pocket in the water heater. There is no place to give way when trying to build the pressure. The system is waterlogged.

I have a variable speed water pump. It's an upgrade from years ago. It works well and as the demand for water (opening the faucet more) increases, the pump runs faster. I can tell almost immediately on mine when the air pocket is gone by the heavy banging of that style pump. The standard Shurflo pumps that Sunline installed are a little more tolerant to the banging when the air pocket is gone, but it could still do it.

To deal with this, and the fact that I drain the water heater after each campout, I installed a hose and drain valve on the water heater. It makes draining water out super easy. When we take our long 1,600 mile annual camping trip, about 3 to 5 travel days into the trip, my air pocket is gone. All I need to do to get it back is, shut the pump off, or shutdown the city water, open the faucet to bleed all pressure out. Then at the water heater, open the drain valve, a little water will flow the stop. I open the safety relief valve and water starts flowing as air goes in the relief valve. I bleed out about 2 to 3 quarts on the ground, shut the drain valve and relief valve, then turn on the water pump or city water and all is fine again for another 3 to 5 days of traveling.

This has never been an issue on a weekend campout, since the heater was drained after each campout, a new air pocket is formed at the start of every trip and the short tow to and from camp is not an issue. Again as long as the heater was drained. It seems to happen more after many towing days, worse on very bumpy roads.

If you really want to solve this issue, installing an air bladder accumulator greatly helps. Shurflo makes a small one, and if you have room, you can use a small house 1 gallon one. They work even better. Those air bladder tanks setup with the correct air pressure, do a good job of eliminating the issues. It is building requirement now in some states that have an incoming check valve (backflow preventer) in the city water supply. The home water heater has to have a bladder tank installed to deal with the issue in a home like this. People with wells, have a well tank with a bladder in it and it takes care of the issue.

Hope this helps and good luck on the trip. If you get anywhere near Ohio, drop us a line. It will be good to see you two again.

John
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Old 01-12-2020, 07:05 AM   #15
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Thanks again john, good information.

On our cross country trip, we have a few sites we want to see and the Ark Encounter is one. That's about 2 hours from you, outside of Cincinnati
Not sure how well be travelling, but I'll let you know when we have the plan.
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Old 01-12-2020, 07:23 AM   #16
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1. The water heater safety relief valve drips/weeps when you are heating water. Even in only on a short time of heating. There is no place for the water to expand into so the pressure builds real quick. The Atwood manuals even talk about the air pocket being lost the the valve weeping.


John


I donít understand why I lose my air pocket so quickly. We normally turn the water heater on first thing in the morning, then off late morning. Same in the evening. I do this.......

IMG_3382.jpg

and my pressure relief valve is dripping water again after about the third heat cycle. Would think the air pocket should last longer than that as it wasnít near as frequent in my previously owned T1700.
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Old 01-13-2020, 12:04 AM   #17
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I donít understand why I lose my air pocket so quickly. We normally turn the water heater on first thing in the morning, then off late morning. Same in the evening. I do this.......

Attachment 6845

and my pressure relief valve is dripping water again after about the third heat cycle. Would think the air pocket should last longer than that as it wasnít near as frequent in my previously owned T1700.
Hi John,

Something is not right. Yours should not be losing the air pocket that fast. A few questions.

1. Did this issue start for you right from the get go, when you bought this most recent camper? Trying to figure out if the issue came with the camper, or worked right and then started doing this.

2. When the problems happens the first time at camp, did you tow with water to camp or fill up at camp?

3. Does this happen on every 2 night weekend campout, or on longer day as well?

4. Do you have to bleed out water just about every day?

5. Trying to understand the time on and off of the heater per 24 hours. It sounded like you turn it on at approx 8:00am then off maybe 11:00am. Then back on maybe 5:00pm and then off again maybe 9:00pm? Please correct me where I have this wrong.

Thanks

John
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Old 01-13-2020, 05:44 AM   #18
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Hi John,



Something is not right. Yours should not be losing the air pocket that fast. A few questions.



1. Did this issue start for you right from the get go, when you bought this most recent camper? Trying to figure out if the issue came with the camper, or worked right and then started doing this.



2. When the problems happens the first time at camp, did you tow with water to camp or fill up at camp?



3. Does this happen on every 2 night weekend campout, or on longer day as well?



4. Do you have to bleed out water just about every day?



5. Trying to understand the time on and off of the heater per 24 hours. It sounded like you turn it on at approx 8:00am then off maybe 11:00am. Then back on maybe 5:00pm and then off again maybe 9:00pm? Please correct me where I have this wrong.



Thanks



John


John,

Itís been like this since we bought the camper (2000 T2370) about 2 years ago.

We used to tow with water in the tank, but have since started draining it after reading your threads.

Seems it starts weeping after the third heat cycle. So I need to bleed it every day and a half.

Your guess on the on/off cycles is very close.

It wouldnít have something to do with the angle of the water heater would it? Itís doesnít sit level as the water heater is mounted at an angle to compensate for the rear wall angle of the camper.

Thanks for your help.
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Old 01-13-2020, 08:57 PM   #19
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John,

It’s been like this since we bought the camper (2000 T2370) about 2 years ago.

We used to tow with water in the tank, but have since started draining it after reading your threads.

Seems it starts weeping after the third heat cycle. So I need to bleed it every day and a half.

Your guess on the on/off cycles is very close.

It wouldn’t have something to do with the angle of the water heater would it? It’s doesn’t sit level as the water heater is mounted at an angle to compensate for the rear wall angle of the camper.

Thanks for your help.

Hi John,

I had forgot about the rear wall taper on your vintage camper. When you get a chance, see if you can measure that angle with a protractor or something. I have a water heater (3 of them even) out now on one of my project campers in the barn. I can tip the heater to the angle you provide and I'll see it that adds anything to your situation.

Here are my thoughts on what is going on. Odds are it is from 2 areas with the first one, being the most likely.

1. Since the problem has been ongoing since you owned it, odds are high you inherited the weeping issue from the prior owner. It may have weeped for a long time before you got it. When they weep that long, and pending the water quality, the safety valve seat can corrode or get a buildup of mineral scale bonded onto the seat. Both can create the ability for the valve weep sooner then reaching the pressure setpoint. The spring technically can weaken too from constant tripping, but I would say they is likely not your issue, more likely is seat corrosion/buildup issues. A heavy hard water buildup with ongoing weeping can look like this.


Since you did a vinegar boil out last year, I think it was you, yours may not look that bad but the damage to the seat could be there

2. The other possible cause, is the temp probe is goofed some and it may be weeping from temperature as well as crud on the seat.

If you want to test and see what is going on, intall a 0 to 200psi water pressure gauge into the drain hole in some fashion and let it so it's thing. If it reaches close to 150psi, it's going to weep from pressure even if the valve is new. Right now I suspect you may be weeping at a lower pressure, maybe 135 to 140 psi which can happen even with some level of an air pocket still there. With the gauge, you can see the root of the problem for pressure.

On my T310 I have a water heater drain hose and a valve. It makes draining water between campouts a breeze. And, for draining out water when creating a new air pocket. Years back I saw mine weeping at camp, dripping out the cover. I screwed a gauge I had on the end and it pegged my 100 psi gage. That was the first time I ran into this. We had changed camps about 4 times by this time. Since then, I have a 0 - 200psi gauge.


The gauge screwed on the drain valve


Since I started doing vinegar boil outs on the water heaters in the last year, I made up a hose setup I could drain with and check pressure to aid in the boil out draining process.


Here is normal water pressure after heating up in a de-scalled water heater. This is with a full air pocket and a pump pressure of 50psi. The pressure rises to 110psi as normally when heated. As the heater cools some, the pressure drops as long as the heat it off. There really is not a large window between normal heating pressure build and reaching the relief point at 150. Only about 40 psi or less.


Odds are high you need a new relief valve. Your older heater is most likely a 1/2" NPT relief valve. Check and see, here is the 1/2" valve, Atwood 91604


Amazon has them or other places
https://www.amazon.com/Atwood-91604-...8969302&sr=8-1

The 2007 Sunlines have a 3/4" relief valve. Atwood must of changed this sometime in the 2006 year or very late 2005.

Hope this helps and let us know what you come up with. I suspect it might be until camping season starts back up. Which is not soon enough!

John
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Old 01-14-2020, 04:44 PM   #20
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Thanks for the info John.

Think Iím going to replace the pressure relief valve first and see what happens. You sound pretty confident in your diagnosis and it couldnít hurt beings itís probably the original valve.

Yes, it might be a while until I report back.......come on spring!

Sorry if I kinda hijacked this thread. I didnít search the forum before asking about my problem.

John
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