Why Very Limited Hot Water Output?

[Tom_T]

Looking for expertise on here as the cause of very limited hot water supply/output.

We have a c. 2007 6 Gal Atwood LP/110v water heater installed in our 1960 Avion T20 by a shop for the PO, which had worked fine on both LP & 110v since we got the T20 in July 2012, & has been sparsely used during our 3-5 long-weekend trips a year (3-5 days each at vintage trailer rallies/camp-outs). PO's only rarely used the hot water as well.

This past year we noticed that it would only run hot for a minute or two - maybe a 1/2 gal +/- of hot, then go cold again.

I cannot think of what part of the water heater with a 6 gal storage tank would only heat a small part of the water, & not the entire tank!?

So a relatively new & seldom used Atwood Water Heater which works on LP & 110v shore power/house current, but only produces a small 0.5-1.0 gal of hot water, then goes cold again!?

Any ideas of what I should look at to fix this problem?

TIA
Tom
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[TG Twinkie]

Check the winterizing bypass valves. Make sure they are in the use mode.

[Tom_T]

Originally Posted by TG Twinkie

Check the winterizing bypass valves. Make sure they are in the use mode.

Thanx TG, but I don't see how they magically closed on their own, but I can check them -

They've never been used by us being in Sunny (wet) SoCal, nor by PO in NM hot southwest AFAIK.

Any other ideas?
Tom
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[Minno]

You might have a build up of sediment in the water heater tank, and need to flush it out.

Kay

[Tom_T]

Originally Posted by Minno

You might have a build up of sediment in the water heater tank, and need to flush it out.

Kay

I've considered that Kay, but is it really possible to have a 6 gal tank 80-90% full with sediment?

We didn't get that much sediment build-up in our 40 gal house water heater after 20+ years in constant use of 4 people without a flushing!?

I do plan to flush it anyway before the next trip, but is there some sensor or other item which could be malfunctioning to cause this very short run of hot water in the tank???

Tom
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[Jacob D]

Originally Posted by Tom_T

Thanx TG, but I don't see how they magically closed on their own, but I can check them -

They've never been used by us being in Sunny (wet) SoCal, nor by PO in NM hot southwest AFAIK.

Any other ideas?
Tom
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Your bypass valve, if you have one, should be closed when using the HW heater. Our '67 A/S doesn't have a bypass so your vintage rig may not either. I did not know we needed one when we replaced our old unit with a gas/electric unit.

Our 10 gal. unit gives us the same problem you describe though, when using electric only. It seems that the electric element doesn't heat the whole tank or just takes a long time to do so. We can run gas and electric together and get almost unlimited supply of hot water in short order. We can then turn the gas burner off and the electric heat is sufficient to maintain the hot water supply for the two of us to shower and wash dishes etc.

[dalecamp`]

Tom T, Does it operate the same on 110 as it does on LP, or does it only do that on LP?
I had a similar problem on my 82-34V, with only LP. Not so much of only a small amount of hot water, but just not hot for very long and seemingly couldn't keep up with the demand of a quick shower.
The water heater seemed to work, I could see a flame, but it didn't seem normal or with much volume.
I checked the gas line thinking it was occluded. Finally found the flexible gas line leaving the regulator and connecting to the steel rigid pipe running under the trailer to be mostly occluded. The tech at the gas company said that the Mercaptan, that is used to odorize LP gas will occlude the rubber hose over time on older vintage trailers, especially ones that are not frequently used. I would take the flexible hose off and see if you can physically blow through it. I could barely force air thru the hose using the power of my lungs. I changed the hose and the problem went away. If your regulator/auto change over assemblies and flex between them and the LP tank are old, it would probably be a good time to changes those too, they aren't too expensive.
Best of luck. Be well.

[Tom_T]

Jacob -

My bypass valve comment was that nobody changed it from before when the heater was working properly. Our new-ish 6 gal. Atwood (2007) is either or 110v LP - so I can't run both, & when it worked properly then both heat sources worked, although 100 took longer.

I tried both LP & 110 overnight, & still only got the short run of hot. It's not even enough for dishes! So my wife is

Dale -

As noted above - it does this on either/both sources, even with 8 hrs +/- overnight to get hot - & still just a short 0.5 - 1 +/- gals as hot, then back to cold.

It's just odd & doesn't fit anything I know from household water heaters of either gas or electric type.

Almost like it's only heating the top or bottom 1-2 inches of the tank - & then never mixing with the cold, until the hot runs out.

I'm on this mystery!
Tom
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[Adventure.AS]

Here is a video from RVGeeks that illustrates a problem getting the water hot if the outside shower is not turned off properly. The symptoms you are having are similar to what they experienced.

https://youtu.be/IsiXaMEneaY

[Tom_T]

Originally Posted by dalecamp`

Tom T, Does it operate the same on 110 as it does on LP, or does it only do that on LP?
I had a similar problem on my 82-34V, with only LP. Not so much of only a small amount of hot water, but just not hot for very long and seemingly couldn't keep up with the demand of a quick shower.
The water heater seemed to work, I could see a flame, but it didn't seem normal or with much volume.
I checked the gas line thinking it was occluded. Finally found the flexible gas line leaving the regulator and connecting to the steel rigid pipe running under the trailer to be mostly occluded. The tech at the gas company said that the Mercaptan, that is used to odorize LP gas will occlude the rubber hose over time on older vintage trailers, especially ones that are not frequently used. I would take the flexible hose off and see if you can physically blow through it. I could barely force air thru the hose using the power of my lungs. I changed the hose and the problem went away. If your regulator/auto change over assemblies and flex between them and the LP tank are old, it would probably be a good time to changes those too, they aren't too expensive.
Best of luck. Be well.

I think you were adding editing while I was replying Dale.

The 30 gal LP tanks & regulator hoses were new in the PO's resto in 2007, but I've changed the rubber hoses there due to age/ozone cracking. Pretty much everything in the LP, plumbing & electrical system was restored in the PO's 2007-08 resto, except the brass LP hard lines.

The stove & 3-way fridge all work fine on LP otherwise, so I think it's not in the LP side (no LP heater in it anymore, but I plan to find & add one back).

I will check the hoses', burner, etc. condition at the WH too (& stove/fridge) when I jump on this maintenance when we have a dry weekend here in SoCal.

They use a similar or same odorizing agent in NG too for homes, but it doesn't seem to react the same with the rubber lined flex hoses required in homes (our home is a 1921 Craftsman, but all that NG flez was changed out over the years).

Whe the LP kicks on at our Atwood, it still seems to be the same level, but worth checking that setting too.

Thanx!
Tom
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[Tom_T]

Originally Posted by Adventure.AS

Here is a video from RVGeeks that illustrates a problem getting the water hot if the outside shower is not turned off properly. The symptoms you are having are similar to what they experienced.

No outside shower here, & the inside shower & both sinks are off securely, with no other hot water leaks dripping under the trailer - so that can't be the problem.

Our vintage trailers were usually more basic than the typical modern TT, although Avion did have a rarely seen outside shower option - just not on ours.

Tom
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[seascape]

Had the same problem with my water heater. After flushing tank it still only put out small amount of hot water. Solution was to remove mixing valve on back side of heater there is a tube that was completely blocked . took vinegar and a piece wire and cleaned tube out problem solved. Hope this helps.
.

[MelGoddard]

“One test is worth a thousand 'expert' opinions”
Sign at Boeing headquarters, posted by test pilot Alvin “Tex” Johnston, c1948

"But will it work in Flin-Flon?"
Sign on Donald Douglas desk,c 1942

[Tom_T]

Originally Posted by MelGoddard

“One test is worth a thousand 'expert' opinions”
Sign at Boeing headquarters, posted by test pilot Alvin “Tex” Johnston, c1948

"But will it work in Flin-Flon?"
Sign on Donald Douglas desk,c 1942

Great quotes from great aviation pioneers Mel, as a pilot myself & someone interested in aviation history!

.... But exactly what are you inferring that I should be testing!?

Otherwise it's really not helpful to my specific query.

Cheers!
Tom
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[Al and Missy]

My 120/Propane heater has two separate thermostat cutoff switches, one for LP and one for electric. If your problem happens with both, it is unlikely that both failed at the same time. Maybe the newer heaters have only one, but mine (2002) has two.

Edit - the newer heaters have a single thermostat for temperature control but two separate emergency cutoff switches. So it is quite possible that your thermostat is bad.

See:http://www.askforatwood.com/manuals/...S%204.9.09.pdf

Al