Water heater failed suddenly - no flow - Montana Owners Club

patodonn · 12-03-2006, 12:23 PM

And, of course it was Saturday night...

DW was "drawing her tub"....turned on the propane heater, opened the hot water faucet in the tub. It ran about 30 sec, then she heard a small muffled "click" or "clunk" noise, and the hot water flow dropped to just a tiny trickle. Same at all faucets in the rig. Cold water OK. I turned off the propane heater, and turned off the electrical heater also. Let it sit overnight to let the water in the tank cool.

After looking at the plumbing, it became evident that the blockage had to be in the hot water tank itself. The kitchen sink hot water comes almost directly from the tank, so no obstruction "downstream" would affect that line. It also was only a tiny trickle flow. I was sure that we were looking at a water tank replacement, so started to get the paperwowrk ready for Monday AM phone calls!!

Sunday AM, I went outside and went through the procedure for removing the anode rod and flushing out the tank...figured it couldn't hurt anything.... LOTS of calcified "junk" came out. The anode rod was in good condition, except for several "clumps" of calcified "junk" on it. It was doing its job. But, there really was a lot of "junk" which came out during the flushing process..

I also undid the connector at the outlet side of the hot water tank. I had hoped to take a flexible wire and see if I could clean out any blockage in the outlet line from the tank. Found the orifice in that connector (at the tank) is really tiny....probably 1/16th or so. I couldn't get anything workable through that small an opening, so just cleaned it out as best as I could. Decided not to take that connector itself off of the tank....too many things could go wrong, at that point.

Put it all back together and "Voila"...works fine.....must have been a piece of crud that was clogging up line in the tank or at the outlet orifice itself. Must have removed it during the tank flushing process.

In summary, if the water flow from the hot water tank suddenly goes to zero or almost zero, let the water cool, then remove the anode rod and flush the tank out thoroughly. Secondly, do that at least every 6 months, even if you know the anode rod is OK. The tank cleaning out seems as important, or more-so, than the anode rod inspection.

Hope that helps someone out if they run into that problem..

Best regards,

Cat320 · 12-03-2006, 12:46 PM

Good advice. As the anode rod slowly disintegrates, all the crude that comes off it as it falls apart is mostly still in the water heater.

JH Sechelt · 12-03-2006, 01:01 PM

Hi JP,

That sounds like that double back check valve you hear about every so often. If it does that again, thats what I would be looking for.

J&D

bsmeaton · 12-03-2006, 01:43 PM

I agree with J&D - sounds like you just found that mystery check valve. A few others have had that plug up from guk lately.

patodonn · 12-03-2006, 02:21 PM

So, where is that little critter?? There was a very low flow "trickle" from all the H/W faucets..

Ishler · 12-03-2006, 02:30 PM

It's on the outlet of the hot water heater. About 1-2 inches long, looks like a short nipple.

patodonn · 12-03-2006, 02:34 PM

That must have been the "orifice" I was seeing. That "nipple" is the brass part which the plastic H/W line connector screws onto, and which screws into the H/W tank itself...correct??

Thanks,

JH Sechelt · 12-03-2006, 03:06 PM

Sounds like it JP,

Its there, so when you winterize the water system, the antifreeze doesn't go back into the HW tank. You could probably replace it with a nipple until you can get a new one.

J&D

tbhd2 · 12-03-2006, 03:25 PM

It's a check valve. It allows flow out of the water tank but won't allow flow back in to the tank. They have been kown to fail. We had a plastic one on our previous 5er and it howled like a dog and very low flow. Replaced it with a brass valve and it worked for a while then it plugged up too. I took it out and replaced it with a standard shut off valve. Just had to remember to close it when winterizing.

mobilrvn · 12-03-2006, 03:37 PM

Hi PJ, we just went through the same thing with the check valve in the hot water heater outlet on the top edge of the heater. Put in a brass one. The cheap plastic really corrodes since it is in the hottest part of the tank. Then had the electric rod go out the next day! We made sure that the electric heater was off while it was worked on. The rod just blew up. I found out too late that you can replace this rod with one that is a little more herky from thier 12 gal. tank.

jrgwdenner · 12-03-2006, 03:52 PM

It really is important to flush out the hot water tank on a regular basis, especially if your water flow has diminished. We greatly improved the water to the commode as well as from the faucet by flushing it out.

sreigle · 12-03-2006, 04:20 PM

It's a five dollar part that failed on our 3295 in the middle of winter, too. RV dealers carry it. One of these days I'll remember to get a spare to carry in this one. It shut off all hot water in our rig, completely. Replaced the checkvalve and no more problem. The checkvalve screws into the tank. The water line screws into the checkvalve.

patodonn · 12-03-2006, 06:53 PM

Guess that is what this Forum is all about. Think I'll pick a "spare" up next time I'm at CW or a dealer that fixes Suburban units.

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