Shower time

[tinstartrvlr]

Good evening all,

 

With my new TT, I have gone from Atwood to Suburban with the water heater. My former Atwood was at a temp that would feel as though it would scald me (I have no idea what the temp was as I never measured it). It had to be tempered with cold water. The Suburban however, is at a preset of 130deg, and while hot, certainly does not feel like it could scald me. (I checked with a meat thermometer-temp is right about 130)

 

So after doing a search of the forums, I came across a bit that mentioned the hotter the water, the longer the shower. I guess that makes sense, although I am not sure why, and it is turning out to be the case with the Suburban.

 

Here's what I don't get. I have the Oxygenics (think I spelled that right) showerhead, which I swapped out of my old TT, and it produces a nice spray without needing a huge turn of the faucets. So, in my previous TT, I just turn the hot water faucet on enough to get a weak spray, and then temper it with cold water, and voila, I have a nice shower. I used to be able to take a 12 minute hot shower before I turned the cold off completely. Even then, the water was comfortable for another couple minutes.

 

In the new TT, I do exactly the same thing. Yet, I can only go about 5 mins before I run out of hot water. I had some problems initially with the heater that seem to be corrected, thanks to all the fine folks on the forum, but I am confused by the short shower problem.

 

Does the temperature of the water really matter, if the flow is the same? I am not using more hot water (the hot faucet is barely on; just enough to get a small flow-when I add cold, I get the desired force/spray, just like I've always done)

 

Any thoughts?

[chirakawa]

Are the two water heaters the same size?

[dartmouth01]

If they are the same size, look at temp of the water, and also that you dont have air trapped in the heater, which would reduce your capacity. You do this by releasing the over temp blowoff valve until water comes out. When the water tank is cold, of course.

[Ray,IN]

Yes temperature matters, especially with only 10-12 gal heater. You can buy a different thermostat for your heater, either a fixed temperature setting or an adjustable temperature model.

You discovered why this is designed for higher temperatures.

[tinstartrvlr]

Same size (6 gal)

 

As far as air, I did try opening the pressure relief valve after water had cooled; water came out, no air. (last week) I have to say I let the water cool overnight, so maybe it was not completely cool, if that matters. From what I learned in my earlier post, there needs to be air in the tank, but I am guessing not TOO much air.

 

So would an adjustable thermo allow me to INCREASE the temp, overriding the preset temperature?

 

Guess I got spoiled by my previous setup. And the only reason I even checked that was because a lady I know who wants to RV complained she wouldn't be able to take a long enough shower, so I timed it! She has now changed her mind about that aspect of RVing!

[Dutch_12078]

Does the temperature of the water really matter, if the flow is the same? I am not using more hot water (the hot faucet is barely on; just enough to get a small flow-when I add cold, I get the desired force/spray, just like I've always done)

 

Any thoughts?

 

The hotter the water, the more the mixture leans toward the cold side to maintain the same flow, extending the available quantity of hot water.

[tinstartrvlr]

Dutch,

 

I get what you are saying, and it makes sense, I think.

 

Guess what I am saying is that I can't take a "hot only" shower-it has to be tempered. So when I turn on the hot water, it is always been at the same flow, meaning just a slight turn of the knob, creating a partial spray from the showerhead. Then I add cold as necessary, and it is enough to provide a nice spray. The only difference in the equation is the temperature.

 

I dunno,,,sometimes the simplest things can screw with my head!

[dartmouth01]

I mentioned letting the tank cool only to make sure you dont scald yourself. The exact temp should not matter.

 

What is the exact model of your new heater?

[KodiakJack]

With any given volume you will reduce it quicker at a higher pressure, i.e. flow. Meaning if your pressure is higher you will run through your hot water faster. I suggest installing a manual ball valve at the shower and adjusting it to reduce the flow once you have the temp where you want it. I use one in conjunction with our Oxygenics shower head all the time.

Later,

J

[WeBeFulltimers]

"Same size 6 gallon".

 

This could be part of the problem.......only 6 gallons. We have a 12 gallon Suburban with 140 degree thermostat and wife & I can take back-to-back showers and not run out of hot water.

[oldjohnt]

I'm running a 6 gallon Atwood dual fired LP or Electric both set at 140 Degrees, 50 PSI 3 GPM pump, and Oxygenics shower head, and I have PLENTY OF SHOWER HOT WATER, PRESSURE AND FLOW. With higher temp hot water I therefore use less (then if it were say 120 degrees) of it balanced with the cold which allows for longer shower times. I love the dual fuel feature as if hooked to non metered electric I use electric heat, but if dry camped, LP, works out great. Sure, I have "exercised" the safety pop off valves at times, but have seen so many (used to be dealer) older RV's where they failed to re seal grrrrrrrrrrrrrr. I have no need whatsoever for any adjustable T stat, but if a person needs one go for it.

John T

[mptjelgin]

From what I learned in my earlier post, there needs to be air in the tank, but I am guessing not TOO much air.

 

There is no way that you can have "too much air" in a water heater, at least not for long! The size of the air bubble is controlled by thelocation of the outlet on the water heater. The air is trapped above the outlet level, and any additional air will come through the line with the hot water. You may get a little spitting and foaming if there is excess air, but it gets purged out of the tank very quickly with use. On the other hand, the trapped air will slowly get dissolved into the hot water over time and that is when you may get the pressure surge when opening a hot tap for the first time or a dripping pressure valve. So you are correct that there needs to be air in the tank, but there is no need to concern yourself with "too much".

[Kirk W]

The normal temperature setting for either Suburban or Atwood water heaters is 140° F when they come from the factory. There are after-market suppliers of adjustable thermostats for the RV water heater that do provide some adjustment. The high temperature is there to extend the amount of warm water you get when you mix it with cold by reducing the amount you need from the water heater and thus also allowing more time for the water temperature to recover as water is drawn from it. Since you tested with a meat thermometer, I'd bet that you still have a typical 140° water temperature by the thermostat.

 

When you changed water heaters, does that mean that you replaced the Atwood that you had before, or did you change RVs as well? If it is a different RV it may be that the distance from the water heater to the shower head has changed.

 

I have the Oxygenics (think I spelled that right) showerhead, which I swapped out of my old TT,

This leads me to believe that you didn't change water heaters but rather you have a completely different RV. The length of the water line between the water heater outlet and the shower is probably different now. There could be a difference in the location of the water lines so that there is more cooling of the water between the water heater and the shower as well. If the previous RV had the water lines run through an insulated wall while the current one runs through an open space where air can circulate, that will mean that there is more heat loss between the outlet of the water heater and the shower. If you can access the water lines you could improve that by insulating the how water supply line, but that is probably about all that you can do.

 

The air at the top of the water heater is designed to be there to supply an expansion space for the water as it heats up and expands. If it isn't there you will see excessive water pressures on the downstream water lines (there is probably a check valve on the cold water inlet) and it can go high enough to cause plumbing problems, or the more common symptom is that the increased pressure will cause the pressure relief valve of the water heater to drip in order to relieve that pressure. It isn't possible to keep an excessively large air space in the water heater tank when it is in use as the hot water leaves the tank from the top at a point just below where the designed maximum air volume falls. Excessive air will come out through the faucets when you first use how water after you fill the tank. The normal level for the air bubble is just below the exit point for the relief valve in typical situations. Changing the amount of air in the tank could increase the volume of heated water, but not significantly. In a 6 gallon water heater, there is usually less than 2 quarts of air space.

[57becky]

The one thing I did not read is, are you taking a 'navy' shower, where you wet down, turn the water off at the shower head, soap up, then turn the water back on and rinse? If not, this will make a huge difference on how long the hot water will last. I we are both taking showers, we turn the gas on along with the electric to get faster recovery.

[tinstartrvlr]

Thanks everyone for the responses.

 

Kirk, the water temp is at 130, which is the preset for the Surburban (according to the manual). The distance is only about two feet more from heater to shower, and it is insulated (actually more so than the previous TT)

 

Oldjohn, help me understand your statement. My onld TT had exactly your setup, and I was pleased as well.

 

But Imagine my faucets had numbers on them, and the amount of water depends on what number I set the faucet at. So I ALWAYS set the hot to #1, regardless of how hot the water is in the heater. I then temper it and create more spray with the cold. Maybe I set the cold on #1, if I want a hotter shower, or maybe I set it on #2, for a cooler shower, etc. The hot faucet provides the warmth, the cold faucet supplies the spray. Point being, I always use the imaginary "setting #1" when I turn on the hot water, so I am confused as to why there is a difference. Anything above 120deg in my opinion is "hot" water, so how hot it is shouldn't matter. It just seems like I shouldn't be running out of hot water so fast.

 

Guess I just have to adapt....Navy shower comes to mind!

 

Besides, I have bigger problems with the TT to worry about.

[tinstartrvlr]

57,

No, similar to Oldjohn, I used to be able to take a continuous shower for 12 minutes without any loss of hot water. Now, I am lucky to get 5 mins. No Navy showers before, but maybe now!

[sundancer268]

Could be the new faucet supply's more water at the "#1" setting than the old faucet so you are using more than you think you are. I do think the extra 10 degrees Temperature difference will cut the duration of the available shower time though seven minutes seems excessive. I know Atwood has a heater out with a built in mixing valve to increase the apparent capacity of the water heater by using extra hot water mixed with cold to supply the fixtures with extra capacity. http://www.atwoodmobile.com/images/waterheaterxt.pdf

[tinstartrvlr]

Sundancer,

 

Thanks. Hadn't thought of it that way,,may be the problem.

 

Anyway, I have adapted by reducing the amount of spray down to nearlhy a trickle on the hot side, and fortunately I can create enough to shower with by adding cold and still keep the temp reasonable, although it is a much less impressive spray.

[Kirk W]

Besides, I have bigger problems with the TT to worry about.

That isn't good news! Anything that we might be able to help with? Warranty issues, I hope.

[tinstartrvlr]

Kirk,

 

Roof problems. See "roof bubbles" post. Think that issue is more of a problem than how long my shower is! Fortunately, it should be warranty.

 

Thanks for asking.