Suburban Waterheater wierdness

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Gnuman

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Joined
Oct 13, 2006
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25
OK, this is a 6 gal Propane water heater built in 2000. Model # SW6P. I'm getting about 3 gals of hot water before it turns cold (I tested this by turning the hot only on and filling a quart container in teh galley sink, until the water was just warm to the touch). I replaced the anode, which, sadly, looked like it had never been changed before. When I changed it out there were heavy "calcium looking" deposits that I had to knock free in order to get the new anode to fit in place. I suspect that these deposits are from hard water. it seems to me that my water heater may be toast, unless I can clean out the tank. Does anyone know of a way to do this? I did flush the tank as best I could after I knocked the bits loose from the anode fitting.

One other bit of strangeness: When I turn on the cold water in the galley (but not in other places) I get a few seconds of hot water first before it turns cold.

the water lines are not insulated, the water heater is located under the stove/oven in the galley, any other info that you need? Any ideas to clean this up? 
 
Hi Gnuman,

My guess is running the hot water only continuously will not get you 6 gals of really hot water. You must remember that, as you use the hot water, cold water will enter the heater from the bottom. It won't take too long before it starts cooling what is still in the tank. These units really aren't made to run just hot water for any length of time. You should be able to run water for a shower and not run out as long as you don't make it a long shower.

Not sure what might be happening with your galley cold water without seeing how it's laid out. It might be the two lines are together at some point close to the sink and the heat is transferred from one to the other.
 
Yeah, that was my guess for the second question, seing that they are not insulated lines. The hot water test was off and on, in 1 qt segments, and I still get only three gals out before it goes to lukewarm. I do not get through even a 15min shower without running out of hot.
 
I'm certainly no expert, but that sounds about like my system. I get ready to take a shower and then turn the water on. I adjust the hot/cold temp to my liking and then step in and hose down. Then I turn a little knob in the center of the shower head, to turn the water off - but retain the same hot/cold mixture.

Then, I soap up. Then, I turn the little knob, again, to turn the water back on so I can rinse off. Enough hot water, that way, for my wife to follow and do the same thing. Enough hot water left to do the dishes, after that.

But not if the water is left running. Can't do any of the above, if we try to run the hot water all the way through.

YMMV.

Ray D
 
In Rv's you learn to conserve water when showing.  You don't stand and linger like at home. As Ray says  even with a 10gal tank as we have.  You have to do with what you have.  If you were backpacking you'd do with even less, maybe a pan of water from the stream and set on open fire and wash with a gal or less.  Not like staying at the Ritz
 
How about the calcium looking deposits? will the new anode clean them up, or am I looking at doing some repairs on the heater?
 
Gnuman said:
How about the calcium looking deposits? will the new anode clean them up, or am I looking at doing some repairs on the heater?
Click to expand...

I would think that your calcium problem is a contributing factor in only getting 3 gals. of hot water. If your WH is filled up to the anode with deposits, then your 6 gal WH may only be a 3 gal heater.

The only way I know of to clean out the deposits is to flush them out through the drain hole. Is the hole that the anode rod mounts in the same as the drain hole or are they two differant holes? If they are separate holes put a hose in the top hole and start digging out the deposit through the bottom hole. If it's the same hole, then the only thing you can do is dig around in there and break up as much as you can then flush it out and repeat the process. If the deposits are too bad you may be looking at getting a new water heater.
 
Heavy mineral deposits interfere with the heat transfer between the heat source and the water in the tank because it forms a crust inside the tank.? You then have a compromised low recovery rate, so it takes a long time to heat your water, leaving you with little at the top of the tank to draw off for use. Keep in mind that whatever amount of hot water that's used is replaced by cold water, so your heated water is diminished both by use and by dilution with cold water. Getting 3 gallons of well heated water from a 6 gallon tank is probably about right, unfortunately. The valve on the shower head works well as previously described for intermittent use without having to readjust for temperature.

Boiler hot water coils in homes can be acid washed several times before having to be replaced, but I don't know that the same can or should be done with a small RV water heater.? Draining and flushing to remove any loose deposits is probably the best you can do.? I flush mine well every spring when de-winterizing even though I have the unit drained and by-passed in cold weather.

If it were mine, and the deposits were that bad that the unit was not serviceable, I'd replace it with a heater that has better efficiency and make my propane go a lot further. It would cost you, but it should save you operating costs and improve performance. If you don't already have a pilotless heater, you could get one and eliminate a standing pilot.? If you have an electric element in the tank, replace the element if it's crusty.

Unfortunately, most RV's don't have much control over the water being used other than with an in-line filter. I believe the sacrificial anode is there to be attacked instead of the tank deteriorating.? I believe you're dealing with mineral deposit accumulations which is a different condition. Replacing the anode won't hurt anything, but it might not solve the problem.

The best solution would be a point of use heater for the shower that could heat the water at the flow rate of the shower. More are showing up in homes, but they're pricey.? I don't know if the new upscale RV's have them, as I'm in the lower priced used class-c price range, so I'm using the typical 6 gallon propane/electric unit also.

Which brings me to the first rule of RV shower use.... never plan on taking a hot shower after your teenage daughter.? ;D
 
You might try adding a little viniger in the tank to see if it helps the calcium. It is normal for the anode to look like crap even after a season. You could also try a flush with CLR to try and clean the debris. Another suggestion is to run the heater on electric and propane, but the previous suggestion of water budget is the most sensible since using propane is expensive and should be reserved for boondocking or for when you have guests and need a quick recycle time.

Nelson
 
Personally, I'd use about a gallon of vinegar to dissolve the deposits. Get some fittings from a hardware store that will allow you to introduce it into the tank from the hot water supply to the kitchen faucet through a garden hose. You'll have to turn the water off first, relieve the pressure, and drain about a gallon of water from the water heater.  Re-connect the hot water line and turn the water on, making sure all faucets are closed first. Turn on the heater and let it get up to temperature, then let it sit for 30 minutes to an hour. Turn the water supply back off, let cool, relieve the pressure again, and hook up your garden hose to the faucet hot water supply line again. Through it, use fresh water to flush the tank through the heater drain. Doing it that way will fluch the flakes out the bottom and not clog the small plumbing lines to the faucets. It could be an expensive repair job if that happens. You may have to repeat the process, but vinegar is cheap. I'd stay away from CLR or other calcium/lime/rust removers as they are far more corrosive and a lot more expensive - also mildly toxic. (lactic acid; gluconic acid; some even use hydrochloric acid (not CLR). Flush the system for a long time before hooking everything back up the way it was. Even so, you may still end up with some flakes in the faucet strainers - just clean them out as you normally would.

Good luck.
 
Interesting... In chat the other night with a forum member I came up with a couple of items to suggest two.

What is intresting is they are basically the two posts prior to this.. Glad to know my thinking was in line  thanks for the support
 
Interesting. . . In chat last night, I met this really nice helpful guy that was able to get me started on the road to actually fixing this problem. Hi JohnD, I'm Gnuman  ;D
 
OK, I finally found that tank saver tool locally (OK, they had to order it, but now they have a few in stock). I put some chemicals in to break up the lime and calcium, and left it hot for an hour, then flushed it with the tool. I got a quarter cup of "bones" out, but not nearly as much as I expected to get. I do have better hot water capacitynow, though, but it still does not recover as well as I would like. After flushing out the tank, and running the hot water for a while, I was still worried last night that I may not have gotten all of the chemical out. Next time (very soon) I'll do it with vinegar, and a higher concentration of it at that. The new anode rod now has calcium stuck to it, by the way, in three lines going down the length. Interesting that it should act that way. The tank saver also kept popping off the end of the cheap $^#^#^@ hose I was using. I got a real good replacement hose end that should work much better. I think now that the calcium does not cover all of the tank, as in some places I got a ringing sound while other places sounded dull. I imagine that is the sound that was described to me before. When it rings everywhere, I'll consider myself done ;)

I will be looking particularly for ringing at the bottom of the tank, as that is most likely to improve the recovery rate.
 
Are you heating the hot water with propane or with electric?  Sometimes - if on shore power - the 6 gal heaters work better when using both.  The propane if working ok heats faster than electric.  Also as you said there is a lot of build-up in the tank - it could be on the electric elements also.  If the anode rod was neglected - the tank itself might soon have holes in it.
 
I would suggest a check valve in the inlet side of the water heater and then I would make sure that the bypass is set properly.  Get a tank wand or make your own for cleaning out the hard water deposits and do that evey 6-12 months depending on how bad the water is.  This also allows you to keep and eye on the anode.
 
I already got a tank wand, and it is helping. I say helping as it will likely take a few flushes to clear out the build up in the tank. This is a propane only unit, and with a pilot as well, not even DSI. Annother thing that has started recently is that I'm having a bit of trouble keeping the flame lit in winds. I have replaced the hinges (they were not even there when I got the rig), and when I got the "new" 24 gallon tanks pressure tested and fitted with new valves, I also got one filled. I'm not sure if the quality of the LPG is the same as the usual place I get it. I also have a new regulator (switching two stage, so I can fill one tank at a time). It seems that the pressure of the LP is not high enough, perhaps. I get a yellow flame instead of a bright blue jet. When I put my fingers over the mixture window, the flame becomes even weaker. Any thoughts on this? If I cannot keep the heater lit, it will not give me any hot water. . .
 
Hmmm, the heater seems to have stabilised. I guess it needs to be started in relatively still air until it has a good flow going. That or this windstorm was worse than the last one. At leas in the last one, I could get the heater re-lit.
 
Regarding the yellow flame:
Have you recently removed the burner for any reason?  I had mine off a couple of days ago and saw a small warning sign that might be of interest.  I have the same suburban heater.
Did you notice the little decal on the door of your water heater that warns that the orifice can fall out easily and be lost when you remove the burner from the gas line? If the orifice did fall out, the burner would still burn, but you would have a yellow flame from an overly rich mixture.
Just a thought.
Herm
 
Thanks for both those points. There is a bit of material in the firebox that needs to be removed (I think it used to be a wasps nest, or someone used a bit of cardboard to try and light the heater). I will be careful of that orifice as well. I will be looking for it at the very least. If I do not find it, I will order one to put in, so I can adjust the flame for it's hottest operation.
 
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