Shower spitting air on hot water side

[tinstartrvlr]

Morning everyone,

 

Thought I would repost this thread since the problem has returned, with a bit of a new twist.

 

The spitting of air is just as it was; after having stopped for several days, it is now back, still in all faucets.

 

The twist is that the other day I very quickly (about 2 mins) ran out of hot water while taking a shower. That has not happened again. The heater was set to electric that day, but has been set to electric many days before with no problem (with regard to enough hot water). Immediately after the shower I switched to gas and checked the heater. Flame was strong and blue and after about an hour, I had hot water again. I set heater to electric at night, and seem to have no problems.

 

Water temp is set to 130deg according to manual, and checking the temp is very close, most of the time. Sometimes a bit cooler than that, but still hot.

 

There is absolutely no sign of a leak anywhere (that I can find). I have opened/closed each valve in case perhaps there was a piece of debris trapped. All seems okay there.

 

I pushed the reset buttons on the heater (Suburban, in case I failed to mention that); can't tell if it made a difference.

 

I am reluctant to bleed off air again as Kirk is correct about needing that air bubble to function properly.

 

Anyone think it's possible that the cold water feed is inadequate somehow and the heater is not filling completely every time, creating extra air, and in the one case, not enough hot water for a shower? And why would it not be that way all the time....

 

I do use an inline water filter and a pressure regulator; just changed the filter and have had no problems with the regulator that I know of. I will say the water pressure seems a little lower in this rig than my previous rig, but it is certainly adequate.

 

I am getting a bald spot scratching my head......

 

 

[Devilishjim]

My guess is you just have air trapped in the line unless you are using the 12V pump and if sucks air then you should be getting air on both Hot n Cold. If hooked to water faucett just let water run for 10 or 15 minutes and the air should work itself out.

[KodiakJack]

Try gently lifting the HW tanks relief valve to let out trapped air. When water flows without air spitting release the valve to let it close again. Might have to do this a couple of time to clear the air. Be careful doing it because hot water can blast out if you open the valve too much.

Later,

J

 

PS Did this a couple days ago because the relief was dripping. Cured that issue too.

[skp51443]

Not purging the air from your water hose before hooking it to the rig when using campground water?

 

If using the RV's pump you might have an air leak on the suction side of the pump, it likely wouldn't leak any water but will let air in each time the pump runs.

[tinstartrvlr]

I was wondering if it had anything to do with the relief valve...I'll give that a try.

 

Jim, have let it run but between showers etc, but seems to not matter. If hot water isn't used for a while, it spits air.

 

Stanley, not using water pump; on city water and have been. Wondering why the air hasn't purged itself by now because it sputters every time I use the hot water, for about 20-30 seconds, then it's fine. No issues with cold water.

 

Thanks everyone. I'll keep poking around and should I find the solution I will post should it be something unusual.

[Kirk W]

If you vent the air from the relief valve you will probably then have problems with the relief dripping each time the tank heats back up once you have used some water from the tank and you may also put high pressures on the hot water lines. There is supposed to be an air bubble in that tank to absorb pressure increases from water expansion. There should be some air in that tank at all times.

 

Is the air only from the shower or is it also from the hot side of the bathroom and kitchen faucets? Since you only mention the shower I was taking it to mean that the others don't do that. If it is only the shower then it don't make any sense for the water heater to be suspect. That air must be getting into the shower line somehow. Is your shower one of the hand-held ones that might be draining back when not in use?

 

Also, you have not told us if you are experiencing this when connected to city water, when using the pump from the fresh water tank, or perhaps both?

[tinstartrvlr]

Hi Kirk,

 

Answering your questions;

 

 

1.All hot faucets, but most noticeable in the shower.

 

2. Haven't tried it yet with the pump. Any thought about why there would be a difference between city connection or the pump?

 

3. The shower head is hand held, but by the way it is mounted, I imagine there is water left in the sagging curve of the showerhead supply line, almost like a p trap.

 

I understand about the air bubble in the tank, and when I bumped the valve a bit very little air came out so I left it alone for the most part. But turning on the shower a few minutes later created some air drama but not as much as usual.

 

Funny thing is after a bit the water flows fine, but if I haven't used hot water over time such as overnight it will be spitting again, as if air is leaking in somehow.

[Kirk W]

Since the water heater is under pressure, I'd not think that it was getting air into the water heater unless there is air somewhere else in the system, which doesn't seem very likely. The fact that you are on city water removes the possibility of the water pump causing the problem by sucking air, as some suggested.

 

How new is the RV, as is this the first time that you have used the RV? If that is the case it is possible that there was air trapped in the water lines somewhere that is causing the problem. If that is the case, or even if the air bubble in the water heater is too large, it should stop happening after a few times of use. I can't recall experiencing air from the system after connecting things for more than one or two times of use, but that doesn't mean that this is not what has happened in this situation. I think that if it were me, I'd just be sure to run the hot for a bit to clear any air for now and see what happens after a few days. A leak in the water system isn't at all likely to put air into the system but it would cause water to leak out. It is a little bit puzzling that it only happens on the hot side as that makes it doubtful that the air is coming in with the city water supply as it should happen to both hot and cold.

 

Do you have a water pressure regulator in use on the water supply? What about a water filter, do you use one of those? If you do use a filter, have you replaced it recently? Is this a problem that didn't happen at first but has recently begun to happen?

[Alie&Jim's Carrilite]

Does your RV have a washer / dryer hookup? If so, do you have a washer hooked up or ??

If there is no washer but you have hookups, try bleeding the hot line for the washer. Chances are there would be an air bubble in the line that the city pressure has to work against. Since your sink faucets are both low flow regulated, the shower is the only fixture that flows enough water allowing the city pressure to drop in the line.

[Yarome]

Did you check your outdoor faucet/shower to ensure it is closed? Is your fresh water tank isolated and valve closed? And there's not a hint of water anywhere under your rig?

 

It's very odd. Once the lines are pressurized from the city water, it "should" be resolved... which means you're getting air from somewhere... and possibly a slow leak, which would concern me. A system wide issue should put the problem child somewhere between your WH and the first intersection. Odd indeed. One leaky faucet.. okay.. but all and only the hot side? Hmmmmm... that's a head scratcher.

[ronmon]

I may be wrong - usually, according to my DW - but I thought that sputtering was a result of not enough of an air gap in the water heater & the fix is to turn off incoming water, turn on the hot faucet nearest the water heater, then lift the lever on the t & p valve to release a bit of water to create more of an air gap. If this helps but not completely fixes it, then do it again.

maybe??

Ron

[Kirk W]

I thought that sputtering was a result of not enough of an air gap in the water heater Nope. That usually happens when there is too much air in the tank. Under proper operating circumstances, the air in the top of the tank is above the opening of the hot water outlet and so it stays in the tank. When there is too little air or none the usual symptom seen is water dripping from the relief valve as the water inside heats up due to the increase in pressure caused by expansion. That is the purpose of the relief that is on all water heaters.

 

It's worth a try, I suppose as it sure won't hurt anything but if there were too little air in the water heater, then where is the air he is seeing coming from?

[Wrknrvr]

Is the hot water hotter than what you think it should be. If so the thermostat may be stuck shut and it is operating on the Eco which shuts of at about 180 degrees.

Which at that temperature it may be boiler some water on the element until the the Eco cuts out.

 

 

 

Possible, Vern

[Dutch_12078]

Under certain conditions, a water heater can separate water into hydrogen and oxygen gases. A chemical reaction between minerals in the water and the anode material can be one cause, with the heat as the catalyst. Changing the anode to a different material if possible can help if that's the cause. With RV's, sometimes just changing water sources as we move from park to park takes care of a gassing issue as the mineral content changes.

[Yarome]

Easy enough to rule out an issue with the WH itself... set the by-pass valves and see if the problem persists.

[Max Death]

First thing I thought about when I read this is could you possibly have a bad or slightly open low point drain for the hot water line? If it has a small enough leak for any reason it could allow water out and air into the system.

 

Just my thought.

Have been wrong before

[tinstartrvlr]

To update,

 

This is a brand new TT.

 

So finally, after 9 days of use, the problem has evaporated. The only thing I did besides use hot water was bleed off some air as suggested earlier in the post. No more sputtering, no water leaks, relief valve seems happy.

 

Thanks for all the responses. I just learned a whole lot more about water heater systems, and I am taking notes in case I have a problem in the future.

 

Great forum, great people!

[Devilishjim]

If you look at your water lines where they come in the cold water heads straight up where the hot water supply goes down to the heater and then coming out of the heater it makes a few up down and around loops ( typical plumber ) before heading to where it's supposed to go. Those loops I would say is where your air got trapped and slowly with time was working up to your faucett to get out.

[KodiakJack]

Air can be compressed. Water cannot. When too much air is in the tank the water can compress the air which thereby increases the pressure. This is very typical on boiler systems where the air relief valve fails to remove air and the makeup expanding water causes the pressure to increase. Of course when water is heated gases are released (air) and is why you find most of the minerals left behind in your HW tank. This in not usually a problem with hot water heaters though where once the air is bled off it does not return without cause (i.e. open to atmosphere at one end). Several of these cause have already been identified. As mentioned the thermostat can be one. My Suburban WH has two control thermostats, one for propane and one for electric. If your WH does too try switching to other energy source. It would be helpful to know what temperature your water is.

Later,

J

 

PS Glad your problem was solved.

 

Edit: Though a failing makeup water valve can cause an increase in pressure it is not the case here.

[Barbaraok]

Under certain conditions, a water heater can separate water into hydrogen and oxygen gases. A chemical reaction between minerals in the water and the anode material can be one cause, with the heat as the catalyst. Changing the anode to a different material if possible can help if that's the cause. With RV's, sometimes just changing water sources as we move from park to park takes care of a gassing issue as the mineral content changes.

 

Ah, no it can't unless your supplying an electrical current directly to the water in the tank. And if it did occur you would have a horrible explosion. You would need very high temperatures to induce thermal splitting. The off-gassing that you see is dissolved O2 and CO2.

 

Barb

[Yarome]

 

Ah, no it can't unless your supplying an electrical current directly to the water in the tank.

 

X2. Although, even by accident, I highly doubt a typical WH would have a sufficient grade or quantity of inert metals to split off any significant amount of hydrogen... I would think. Might be fun to try though...

[Dutch_12078]

 

Ah, no it can't unless your supplying an electrical current directly to the water in the tank. And if it did occur you would have a horrible explosion. You would need very high temperatures to induce thermal splitting. The off-gassing that you see is dissolved O2 and CO2.

 

Barb

 

So then we can assume that A.O. Smith, Atwood, Suburban, and others include warnings like the one below in their water heater manuals because they don't know what they're talking about? Perhaps you could enlighten them...

 

 

A.O. Smith Instruction Manual (page 4)

 

Suburban Water Heater Manual (page 2)

[Barbaraok]

Dutch, that isn't producing O2 and H2, which is what you said. There is a chemical reaction that can occur when very alkaline water is in contact with aluminum for a period of time, but it does not produce O2, which is what you said was happening. And this has to be very basic alkaline solution - usually a pH of 12 or higher, not something that you are likely to encounter in normal water systems. The warnings are typical CYA lawyer type - not that it couldn't happen, but I'd like to see their identified instances of H2 gas being produced by their heaters.

 

Now producing H2 gas is something that batteries that are overcharged do quite easily.

 

Easy fix if you haven't used water heater for a longer period of time (stored for winter, for example) is to flush the water heater (always a good idea) and fill with fresh water before turning on heater.

 

Barb

[Dutch_12078]

Dutch, that isn't producing O2 and H2, which is what you said. There is a chemical reaction that can occur when very alkaline water is in contact with aluminum for a period of time, but it does not produce O2, which is what you said was happening. And this has to be very basic alkaline solution - usually a pH of 12 or higher, not something that you are likely to encounter in normal water systems. The warnings are typical CYA lawyer type - not that it couldn't happen, but I'd like to see their identified instances of H2 gas being produced by their heaters.

 

Now producing H2 gas is something that batteries that are overcharged do quite easily.

 

Easy fix if you haven't used water heater for a longer period of time (stored for winter, for example) is to flush the water heater (always a good idea) and fill with fresh water before turning on heater.

 

Barb

 

I'll concede I could be wrong about the process breaking the water down, but if it is a chemical electrolysis process...

 

I think you'll find it occurs more often than you might think:

 

"I did a burn test on the "air bubbles" after the gas alarm started going off and the bubbles did burn. So I'm pretty sure that I was having some form of electrolysis going on in the tank. There are no air bubbles with the cold water. The tech support guy tried arguing with me that hydrogen gas production is normal, even what I was getting. It is a product of the reaction at the anode, but I got 10 years worth of gas production in 4.5 months and that just doesn't seem safe to me at all."

 

http://ths.gardenweb.com/discussions/2527954/hydrogen-gas-generation-in-my-water-heater (scroll down to the first 11/08/09 post by the OP)

[Kirk W]

I must agree with Barb. In addition, an RV water heater is far smaller than the one in your house and so the potential if that did happen is far lower. Most homes have 30 to 50 gallon water heaters, while RVs usually have 6 gallon and no more than 10 gallon. In addition, if you read this thread the OP was using the water heater, while your warning label is for a "water heater that has no been used for a long time."