# Shower Runs Cold In The Ob



## 4dollars (Nov 26, 2008)

We have a 26RKS and was wondering if any others have experienced the same problem we have. When taking a shower we turn the water off at the shower head and when you turn the water back on the water is cold and takes a couple seconds to warm back up.

It seems once you have the water set to where you want it and turn it off, the cold water works its way to the shower head so when you turn in back on you get a blast of cold water.


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## CamperAndy (Aug 26, 2004)

Typical reaction from the head. What happens is the cold water maintains a slightly higher pressure. When you close the head the higher pressure cold water pushes into the hot water pipes and then when you open the head you get that cold slug.

If there was a check valve at the faucet, hot and cold, then you would not get that slug of cold.


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## mountainlady56 (Feb 13, 2006)

I always took the shower head down and held it when I cut the water back on. Otherwise, BRRR!!!
Darlene


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## Justman (Jul 22, 2006)

Same issue here. I just turn it away when turning it back on. Makes taking a shower exciting!


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## Husker92 (Feb 11, 2006)

It wakes you up when you forget.







I took the shower hose out of the high loop so I could point it to the drain easier.

Happy Outbacking!


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## Oregon_Camper (Sep 13, 2004)

Husker92 said:


> It wakes you up when you forget.
> 
> 
> 
> ...


X2...that is the only way to not get that darn blast of cold water.


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## battalionchief3 (Jun 27, 2006)

I have the same problem and I hate it. I take quick showers so I usually dont even turn it off. I let it get good and hot, run the elec and propane and keep moving.


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## Dan H. (Jul 14, 2006)

CamperAndy said:


> Typical reaction from the head. What happens is the cold water maintains a slightly higher pressure. When you close the head the higher pressure cold water pushes into the hot water pipes and then when you open the head you get that cold slug.
> 
> If there was a check valve at the faucet, hot and cold, then you would not get that slug of cold.


Check valves at the faucet?? Is this a MOD I am not aware of ?









Please advise me if you know of one.

Thanks


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## NDJollyMon (Aug 22, 2003)

HAHAHAHA! I remember that cold blast of water! Aim that baby away from you when you turn it off for a "Navy shower"!

I don't worry about it anymore. Got a 20 gal hooked to a permanent sewer....ahhhhh.

Good luck. Tell the family...nah...let 'em find out the hard way!


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## California Jim (Dec 11, 2003)

Ah yes, the RV shower menace. I guess we all just get used to pointing the water at the back wall for 2 seconds when the water comes back on.


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## CamperAndy (Aug 26, 2004)

Dan H. said:


> Typical reaction from the head. What happens is the cold water maintains a slightly higher pressure. When you close the head the higher pressure cold water pushes into the hot water pipes and then when you open the head you get that cold slug.
> 
> If there was a check valve at the faucet, hot and cold, then you would not get that slug of cold.


Check valves at the faucet?? Is this a MOD I am not aware of ?









Please advise me if you know of one.

Thanks
[/quote]

Not really but it is a fix that will work. You would add check valves to the water lines just before they go into the faucet.


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## Compulynx (Oct 15, 2008)

CamperAndy said:


> Typical reaction from the head. What happens is the cold water maintains a slightly higher pressure. When you close the head the higher pressure cold water pushes into the hot water pipes and then when you open the head you get that cold slug.
> 
> If there was a check valve at the faucet, hot and cold, then you would not get that slug of cold.


Check valves at the faucet?? Is this a MOD I am not aware of ?









Please advise me if you know of one.

Thanks
[/quote]

Not really but it is a fix that will work. You would add check valves to the water lines just before they go into the faucet.
[/quote]

Actually, you would only need a check valve on the hot water line. Then the cold would not flow into the hot water line to equalize the water heater tank pressure. It would not go the opposite way. The check valve could probably also be placed at the hot water heater outlet, which may be easier to plumb and get to.

C


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## 4dollars (Nov 26, 2008)

Thanks CamperAndy and all for the comments.

After reading your suggestion on the check valve I did some searching on the net and found someone who did the mod on their TT. I think I might take a look at the OB shower and see if I might be able to add the check valve. I know it would make the DW happy









http://www.motorhomemagazine.com/boards/in...id/21981346.cfm


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## Compulynx (Oct 15, 2008)

Here is what we need to do the mod. No other fittings should be needed. Just cut, make sure arrow is pointed right, and push to connect.

2 sources

http://www.acehardwaresuperstore.com/shark...432.html?ref=42

http://www.pexsupply.com/product_dtl.asp?p...cme&cID=786

C


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## CamperAndy (Aug 26, 2004)

I am glad I was able to help you on this shower issue, it seems I was not able to help others earlier in the week when an other shower issues was raised.

Make sure you get some photos for the mod when you do it.


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## Oregon_Camper (Sep 13, 2004)

Compulynx said:


> Here is what we need to do the mod. No other fittings should be needed. Just cut, make sure arrow is pointed right, and push to connect.
> 
> 2 sources
> 
> ...


You going to do this mod?


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## Calvin&Hobbes (May 24, 2006)

Oregon_Camper said:


> Here is what we need to do the mod. No other fittings should be needed. Just cut, make sure arrow is pointed right, and push to connect.
> 
> 2 sources
> 
> ...


You going to do this mod?








[/quote]

I am... now.

Thats what I love about this site. I had the same issues, like everyone else. Either a quick, non-stop shower, or one with a cold blast of reality in the middle. I just delt with it. But now I've seen this problem solver, and like an "Info-mercial", I have to have it! Maybe Billy Mays can pitch it, with his jet black dyed hair (or Vince, from Sham-Wow).

Now I'm off to see if my local plumbing store have those 1/2 inch pex "sharkbikes"....


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## Compulynx (Oct 15, 2008)

Oregon_Camper said:


> Here is what we need to do the mod. No other fittings should be needed. Just cut, make sure arrow is pointed right, and push to connect.
> 
> 2 sources
> 
> ...


You going to do this mod?








[/quote]

Has a cat got a running gear?









C


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## Path4ground (Sep 14, 2008)

Compulynx said:


> Here is what we need to do the mod. No other fittings should be needed. Just cut, make sure arrow is pointed right, and push to connect.
> 
> 2 sources
> 
> ...


Thanks for sharing the info; this one is on my short list. Hope to pick up the check valve today!!


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## GarethsDad (Apr 4, 2007)

SharkBite Part# U2008-0000A 1/2" pex check valve. http://www.outbackers.com/forums/index.php...i&img=11472 .James


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## Compulynx (Oct 15, 2008)

GarethsDad said:


> SharkBite Part# U2008-0000A 1/2" pex check valve. http://www.outbackers.com/forums/index.php...i&img=11472 .James


You are lucky. Looks like web order for me. No one around here stocks it.

C


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## GarethsDad (Apr 4, 2007)

Compulynx said:


> SharkBite Part# U2008-0000A 1/2" pex check valve. http://www.outbackers.com/forums/index.php...i&img=11472 .James


You are lucky. Looks like web order for me. No one around here stocks it.

C
[/quote]
While drinking my coffee I called my plumbing supply house for pex crimp checkvalves and the counter guy said that they don't stock them but that he could order them or he had two SharkBites in stock. I told him to hold them for me and I'm on my way. James


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## 4dollars (Nov 26, 2008)

I'm going to try to find one today myself. The shark bite fitting looks a lot easier to do than the other way I found. As they say "keep it simple, stupid" and for me the simpler the better.


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## Oregon_Camper (Sep 13, 2004)

Looks like a simple mod..

Anyone of you that are doing it...please post a few pictures of the process.


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## GarethsDad (Apr 4, 2007)

Oregon_Camper said:


> Looks like a simple mod..
> 
> Anyone of you that are doing it...please post a few pictures of the process.


Here you go http://www.outbackers.com/forums/index.php...i&img=11481. If you open up the access panel for the tub and you can reach the water lines you should be able to add the checkvalves with out pulling the tub. James


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## Calvin&Hobbes (May 24, 2006)

That was fast!


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## GarethsDad (Apr 4, 2007)

Calvin&Hobbes said:


> That was fast!


Well I already had the tub out and was planning on installing the full tub this morning when I came across this thread. I would have been bummed if I read this thread tomorrow. James


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## CamperAndy (Aug 26, 2004)

GarethsDad said:


> That was fast!


Well I already had the tub out and was planning on installing the full tub this morning when I came across this thread. I would have been bummed if I read this thread tomorrow. James
[/quote]

Timing is everything!


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## MJRey (Jan 21, 2005)

Like others I thought this was just something I had to live with. I'll be doing the mod before our next trip out. This should also help save a bit of water as well since I won't have to let the water run while the temp gets back to a reasonable level. One question though, does it matter how far from the faucet you put the valve? I would guess that as long as it stops the backflow it can be wherever is most convenient to reach.


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## CamperAndy (Aug 26, 2004)

MJRey said:


> Like others I thought this was just something I had to live with. I'll be doing the mod before our next trip out. This should also help save a bit of water as well since I won't have to let the water run while the temp gets back to a reasonable level. One question though, does it matter how far from the faucet you put the valve? * I would guess that as long as it stops the backflow it can be wherever is most convenient to reach.*


True but closer is better.


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## CamperAndy (Aug 26, 2004)

Guys I need to clarify why you get the cold slug of water and why you need two check valves, it is not just back flow into the hot water pipe. As many of you know there is already a couple of check valves in the hot water system and there is one at the outlet of the hot water tank that prevents back flow in to the hot water tank. These check valves create pressure drop that the cold water pipes do not have.

When you close the shower head it is never a positive shut off and will dribble. This dribble flow is lower then the lift pressure for the hot water system check valves so from the faucet to the shower head all you get is cold water flow. You can also get some back fill into the hot water system but it should only be a little bit.

Installing a check valve in both the hot and cold water pipes to the shower faucet feed should place a closer matched pressure drop to the water that feeds the shower faucet. So with the head closed the dribble flow will be more or less a mix of both hot and cold instead of just the cold water.

You still need to exercise caution when you turn the shower head back on but the issues of cold water slug should be reduced.


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## Path4ground (Sep 14, 2008)

I haven't done this mod yet, but my thoughts were to add the valve on the hot side, and leave the cold side as is for two reasons: 
First, having valves on both lines would keep the pressure high on the lines between the check valves and the shower cut off. (I was concerned about leaks when at pressure for a period of time until pressure bleeds off??.)
Second, when the shower is cut off, the mixed water would back into the cold line when the pressure resides, instead of the hot side; this hopefully would eliminate the cold surge as well.
At least thats my thinking as of now; until someone can influence better judgment on my thought process


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## gone campin (Jan 29, 2006)

I let it lay on the floor and hold it away when I turn it back on.

Linda


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## Compulynx (Oct 15, 2008)

Path4ground said:


> I haven't done this mod yet, but my thoughts were to add the valve on the hot side, and leave the cold side as is for two reasons:
> First, having valves on both lines would keep the pressure high on the lines between the check valves and the shower cut off. (I was concerned about leaks when at pressure for a period of time until pressure bleeds off??.)
> Second, when the shower is cut off, the mixed water would back into the cold line when the pressure resides, instead of the hot side; this hopefully would eliminate the cold surge as well.
> At least thats my thinking as of now; until someone can influence better judgment on my thought process


Not going to start an argument here, but properly designed check valves will not lower the pressure. An elbow in the line would cause more restriction than a check valve. You only need one on the hot side, but if anyone wishes, do both.

The problem is simple hydraulics. The Hot water tank has some air trapped in the top, and air will compress, unlike water. so some of the cold water rushes in the hot water line at the faucet until the air compresses, causing the problem.

NOW, I will introduce another thing to think about. If you, like me, have an attenuator tank on the cold side, you just MAY need 2 check valves to keep from getting scalded. The flow could actually reverse from the hot water line equalizing before the cold side under certain conditions.

As for the pressure buildup with 2 check valves, I have yet to see an wand that does not drip a little when off, so do not worry about that.

I am going to do the hot only, then see if I get hot water feedback because of the attenuator. If so, I will do both.

If you do not have an attenuator, you only need the hot side done.

And you won't hurt anything doing both anyway, except spend another 14 bux for the extra valve.

C


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## CamperAndy (Aug 26, 2004)

Compulynx said:


> The problem is simple hydraulics. The Hot water tank has some air trapped in the top, and air will compress, unlike water. so some of the cold water rushes in the hot water line at the faucet until the air compresses, causing the problem.
> 
> C


No argument but there is already a check valve in the hot water line as it exits the water tank so the air pocket in the water tank has no influence on the issue. All check valves will have a pressure drop, it can be very low for a specific and well designed one but the cheesy ones that you will find in the trailer have at least a 2 or 3 psi cracking pressure.

Let us know how the one new check valve works out.


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## Dan H. (Jul 14, 2006)

Great theoretical discussions guys









Let's start modding and see if the results indicate which solution is best for our time and money.









I am standing-by for some data


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## Compulynx (Oct 15, 2008)

Yep, it is gonna be kinda interesting to find out what works. Like CamperAndy said, there is already a check valve on the outlet side of the heater, so my theory about the air in the tank does not hold water (pun intended).

Now I wonder if the cold water actually rushes into the hot line when you turn the shower head back on, because it would take less time to get the water moving on the cold side, since it is closer to the campground inlet.

Then again, seems like the charge built up in the heater tank would start the hot water first.

Or is the cold water even getting in to the hot line. Maybe it is just the first to deliver to the wand when you open it back up, while the hot side is getting flow moving.

The more I think about what actually is happening, the more confused I really am.

I will have to wait a week or so to test, since I got to get it by web. No one here has one. Plus, I am going under the knife Wednesday to get a bad gall bladder removed...







, so I will be out of commission for a few days....

C


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## borntorv (Apr 13, 2004)

Interesting thread folks. In reading some of the comments from an attached link I noticed a word of caution about adding check valves if you rely on the low point drains for winterizing. The comment was that the water in the lines between the valves and the shower head will be "trapped" and not drain. They suggest that the pink fluid needs to be used to avoid freezing. Does that sound correct to you "experts"? Also, I assume if a person uses air pressure to blow the lines during winterization that would also work to clear the lines? Just want to make sure I'm not creating one problem in order to solve another.

Greg


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## CamperAndy (Aug 26, 2004)

borntorv said:


> Interesting thread folks. In reading some of the comments from an attached link I noticed a word of caution about adding check valves if you rely on the low point drains for winterizing. The comment was that the water in the lines between the valves and the shower head will be "trapped" and not drain. They suggest that the pink fluid needs to be used to avoid freezing. Does that sound correct to you "experts"? Also, I assume if a person uses air pressure to blow the lines during winterization that would also work to clear the lines? Just want to make sure I'm not creating one problem in order to solve another.
> 
> Greg


Pink or air will prevent it from being an issue.

A word of caution to all those that just drain the system, be careful as you can not drain the entire system with just the low point drains. Even if you do not install the check valves mentioned in this thread.


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## 4dollars (Nov 26, 2008)

OK ordered my shark bite check valves. Hopefully the'll get here by next weekend so I can get them installed in the OB and tested before we leave on April 9th for Pismo State Beach for Easter.

Has any one thats installed them test them yet?


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## Path4ground (Sep 14, 2008)

Compulynx said:


> Here is what we need to do the mod. No other fittings should be needed. Just cut, make sure arrow is pointed right, and push to connect.
> 
> 2 sources
> 
> ...


I can't seem to find this part locally; My online order is in as of today! Thanks for the link Compulynx!!


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## Compulynx (Oct 15, 2008)

RESULTS ARE IN!!!!

Well, I got my check valves installed and tested out the shower today.

The results are mixed, and surprising to me.

The check valves did shorten the cold water burst from a couple seconds to maybe a half second, but did not stop the cold burst completely.

Both valves (sharkbites) were installed about 2 inches below the shower valve on cold and hot lines.

Although I think the improvement was worth the work, do not expect a 100% lack of cold water when turning the shower head back on.

-----
I am now doing a rethink of the whole process and am thinking that like CamperAndy says, the restrictions on the hot water path (lines, check valves, fittings, etc) are impeding the hot water flow when you reopen the shower head just enough to let a little burst of cold water slip in there.

-----

Others doing this mod. Post your results.

C


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## OutbackPM (Sep 14, 2005)

Compulynx said:


> RESULTS ARE IN!!!!
> 
> Well, I got my check valves installed and tested out the shower today.
> 
> ...


I have been looking at this post as I also have water heater problem (see Hot Water Tank Mixing Valve-cool Water) but that is different.

Here's my take on this. If you have a check valve at the hot water tank how is cold water going to go back into the hot even if the cold is at a higher pressure. I think the hot stops flowing when you press the shower head button because as already mentioned the cold is at a higher pressure so the flex line between the taps and the shower head fills with cold. When you resume the hot can now flow but there's a ton of cold water ahead of it. So in theory the check valve in the hot would not stop it. A check valve in the cold would even up the pressure between hot and cold so not so much cold would flow.

Having said all that the proof is in the pudding. Look forward to more results


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