Cannot get continuous hot water — resolved by adjusting mixing valve

2Jills

Hi
I have a new 2020 Tab 400 with the Alde 3020.  When I turn on hot water at either sink it takes a while for the water to get warm but then it goes back to cold after only a few seconds. 

Alde shows water temp is 117 degrees and is running off shore power (15 amp connection to house). Bypass is in normal position. All valves are in the correct position. Mixing valve is set to max. Hot water hose feeding into the mixing valve is warm to touch. 

What am I missing?    

Thanks. 

bergger

You'll need to actually adjust the mixer valve itself.  Loosen the screw on top of it and slightly lift up the  plastic knob, turn it then reset it onto the brass fitting.  The knob is simply not turning far enough to get consistent hot water flow and needs to be opened more.  There is a thread on this posted but sorry don't have the link to it.  

Bayliss

@2Jills, review this discussion thread:

https://tab-rv.vanillacommunity.com/discussion/5018/no-hot-water-at-kitchen-sink-bathroom-sink-had-hot-water#latest

2Jills

Thanks @Bayliss. I found that discussion and made the adjustment. Everything seems fine now. Thanks a bunch. 

jkjenn

Also, check your Alade control panel. Is the pump set to continious?

Denny16

And is the Alde bypass/cutoff valve in the correct position.
cheers

N7SHG_Ham

@jkjenn the pump will be off unless you want to heat the cabin by circulation of the glycol. For just hot water there shouldn't be any glycol flowing around through the convectors.

Sharon_is_SAM

Question:  if the control panel is set to Thermostat, then cabin heat is temperature dependent.  If set to Continuous, will glycol circulate regardless of temperature?

jkjenn

Sharon_is_SAM said:

Question:  if the control panel is set to Thermostat, then cabin heat is temperature dependent.  If set to Continuous, will glycol circulate regardless of temperature?

I had to change this setting on my T@b to get more than a minute of hot water.

TNOutback

@Sharon_is_SAM, it appears the circulation pump is turned off for space heating (if it was previously set in continuous mode).

Sharon_is_SAM

@TNOutback - I saw what you posted from the manual as well.  But, I don’t think the 320 has the floor heating function.  Also, the pump is active for cabin heating.  

I think the mystery is if Continuous is selected, does the pump continue to circulate even if you are not trying to heat the cabin?  If that is true, then the cooled off glycol re-enters the heating chamber and reduces the ability to maintain the water temperature.  IF this is true, I think that may explain @jkjenn’s observation that she had brief hot water when the pump was on Continuous.

TNOutback

@Sharon_is_SAM I read it to mean that if extra hot water is selected, the pump for cabin heating is stopped for 30 minutes; it is overridden. I’m not sure if a continuous pump mode is even an option, since as you point out, we don’t have floor heating in these units, nor are they connected to an engine for preheating.  I may be reading that wrong, but that’s what I got out of it:  if you want extra hot water, the circulation pump is turned off for 30 minutes, regardless of cabin heat setting.  That would make sense to me, since a continuous pump would indeed rob the boiler of hot water-making capability.

2Jills

My pump is set to therm. Previously I was only getting a second or two of hot water.  When I changed the mixing valve as described in the link @Bayliss noted then I was able to get continuous hot water.  No other changes were made to what I described in the original post.  And I do not have floor heating.  I have not tried the shower yet so maybe my experience will change.  Hopefully all is good.  

Bayliss

Maybe a bit redundant to what has already been posted above, but here are my notes on the subject:

If the Alde pump is set to Continuous ("Cont.") circulation (as opposed to Thermostat ("Therm") driven), you cannot choose the partially shaded icon.  In the Continuous pump mode, you can choose the “Boost” (fully shaded icon), which stops the glycol circulation for 30 minutes and allows the water to get extra hot for showering.  So, if you keep the pump setting in the Therm mode, you can adjust your water temperature to partial shade AND use the Boost.  

“BOOST” MODE:  When you set the shaded area at full, the “central heating” of the cabin is turned off and the glycol pump will stop circulating (thus not heating the camper cabin) for approximately 30 minutes.  This focuses the heating on the water tank so that the water can be super-heated.  After that, the system will revert back to the normal cabin heating/circulation mode.  It is only when you want extra hot water, such as when you want to take a hot shower, that you may want to use the “boost” setting, as indicated by a fully-shaded hot water symbol.  “Boost” can be used on either electric or propane, but the Alde is more efficient when operated on propane.

CENTRAL HEATING PLUS HOT WATER:  If you have the temperature set so that you are heating the cabin, plus have ½ of the shaded icon filled, you will have BOTH cabin heat and hot water at the normal setting (approximately 120-125 degrees.)  Normally, you will leave the shaded symbol half-filled.  However, if you are not in need of hot water, leave the shower water icon empty and the water will only be heated to a “warm” temperature. 

ChrisFix

2Jills said:

My pump is set to therm. Previously I was only getting a second or two of hot water.  When I changed the mixing valve as described in the link @Bayliss noted then I was able to get continuous hot water.  No other changes were made to what I described in the original post.  And I do not have floor heating.  I have not tried the shower yet so maybe my experience will change.  Hopefully all is good.  

@2Jills
I fixed my hot water supply issues this way as well. 
Please be careful though, because my hot water is now VERY hot...which is what I wanted so I could mix the relatively small volume of hot water with cold and have plenty of warm water for a shower...but it feels hot enough to scald I think...So please just be super careful to understand just how hot it is. Especially if you're using the hot water "boost" feature.

And to add a small anecdote...I'm currently camping in the Blue Ridge mountains and staying at  a full hookup site. After hiking for 6 hours this morning I just had a wonderful long hot shower - plenty of hot water once you adjust  the mixing valve.

Denny16

You also have the Alde Flo aux water heater on your Alde system, which should give you fairly close continuous hot water in conjunction with the Alde heater.  On pre 2020 TaB 400s that do not have the Aux Flo system heater tank, having continuous hot water is more of a challenge, which is where increasing the hot water temp started to help get more hot water.
cheers

2Jills

@Bayliss - that's an excellent description of the functionality.  Thanks.

Denny16

You are welcome.  We have a 2018 TaB400 and are considering adding the aux Flo tank to our system, which requires the newer Alde 3020 heater, which we have.  I did a lot of research into what was required to add the Flo tank.  It ends up being a basic plumbing job, but requires space next to the Alde for the Flo tank, and plumbing the Flo in front of the main Alde unit.

The water source (cold) is connected to the Flow tank, then the hot water output is feed to the former cold water input on the Alde main unit.  The glycol goes from the Main Alde heater to the Flo, than to the floor heaters.  Next you need to add another overflow drain for the Flo tank.

Here is a complete factory install, the Red tank is the Flo aux water tank.: