Hot water, then cold water, then hot on a 400

falcon1970

I remember (I think) a post about a hot water problem.  Somebody was getting hot water for a few seconds, then cold water for awhile, then hot water again, and so on.  I have tried searching for that post but cannot find it.  Does anyone remember such a post?  I am having the same issue and would like to know what the eventual resolution was.
Maybe there never was such a post and I am (as my brother says) remembering things that never happened.  If there was not a post and solution, would anyone have any ideas about why this would be happening?  I have a 2019 TAB 400 with the Alde 3020 and the Alde Flow system.  The mixing valve is set to max and the few seconds of hot water I get is indeed hot.  There are no "odd" sounds from the pump or the lines and no sputtering from the faucets or toilet.  There seems to be good pressure at the faucets.  I have restored the air gap in the Alde system.
Any suggestions would be greatly appreciated.
As an aside, even though I have been working this issue while on shore power, will the Alde heat water using only the battery?

ScottG

I think there have been several posts to that effect, but I can't put my finger on any of them specifically.

I can answer your last question, though...  No, the Alde can not heat water using only the battery. The circuitry requires 12V to operate, but the heat must be provided by either propane or 120V shore power.

falcon1970

@Scott G
Thanks for the info about 12v.
I'm glad to hear that you also remember posts of the nature I was looking for and that I'm not off in LaLa land.  Or if I am, I'm not alone.

pthomas745

I think it might be a thread on this subject.  The symptoms are the same.

https://tab-rv.vanillacommunity.com/discussion/2676/little-hot-water/p1

If you are comfortable with Google, you can get much better results from their search operators in your web browser, and limit the search to this site.  This thread has details.

https://tab-rv.vanillacommunity.com/discussion/5920/cool-search-tip

Verna

@falcon1970, if my Alde furnace is on, I get warm water, then cold, then hot, then the temp I want. This takes all of about 7 to 8 seconds.

Now that the Alde furnace is off, I get cold water, hot, then my temp in about 5 to 6 seconds. 

I figure it does take a bit to move the hot water and then mix it. It’s fine with me. 

falcon1970

@Verna
Thanks, I was thinking it might be just that the water in the lines had to be moved out of the way, but it seems to take longer than I expected and I have yet to get straight hot water from the faucets.  At the moment I'm running the Alde water only with no cabin heat.  I'll keep playing with it and see what happens.

Sharon_is_SAM

@falcon1970, with the Alde flow, there is a quantity of water that is kept warm, then when you call for hot water by opening the tap, the water moves to the hot Alde water tank where it is quickly heated.  I am jealous because it sounds like you can take a regular shower instead of a navy shower!

falcon1970

@Sharon_is_SAM
Well, I don't know about showers.  I'm still trying to figure this system out.  If the TAB and I are still here tomorrow after the tornados move through I'll be back out in the driveway experimenting.  From reading the Alde manual it does seem that you can have continuous hot water for as long as you want, or as long as the water lasts--once you get hot water that is.