Water gets warm but not hot

geoB

On our first trip out this year, with city water and shore power connections, the hot faucets never showed anything better than tepid (~70° - 80°) water. Last year (our first in a 2021 400 Boondock) hot water temperature was just fine. If there was anything unusual in the dewinterizing process it was the first several seconds of running hot water after the bypass valves were opened. The sputtering had a very foul smell. As the flow ceased to sputter cold clear water came out of the faucet.  On our trip we noticed that it took a while (I ran the outside shower for several minutes) for there to be a constant flow of warmish water - most likely because I hadn't run the 3 gallons or so as suggested in the manual.

What to do?

pthomas745

Check your bypass valve setting again.  That could be one cause. (Recheck all the valves for "camping mode".)

And, have you ever adjusted your mixing valve?  You may have the "red cap" thermostatic mixing valve, which is fairly easy to deal with.  If you don't have this "red cap" mixing valve, look for a "black cap" valve with the hot and cold water pipes around it.  It will be a different procedure to adjust.

https://tab-rv.vanillacommunity.com/discussion/12718/new-thermostatic-mixing-valve#latest

geoB

[Note: this may be a repeat of a message sent a half hour ago via gmail]

Thanks for the quick reply. Below is a photo of the current unchanged state.

Additional data: Alde controller, Services, Water temp = 118°; temperature of water at galley sink = 91°.

[Edit: yesterday while camping water temp read 167°; above reading is after driving home.]

Small red dot to left of the red hose is set to 2 1/2, which I set last year. Do you see anything amiss?

Sharon_is_SAM

@geoB
The valves in your photo look fine?  The glycol pump setting of 2.5 controls the glycol circulation and is adequate.  Make sure the Alde is set to “Therm” rather than “Continuous”.  Continuous mode circulates the heated glycol constantly and returns cooled glycol to the Alde.  The Alde in turn uses that “warm” glycol to heat the water - this may account for a cooler water temp.

Other factors that effect water temp = starting with very cold water, cold ambient temp, thermostatic mixing valve needs adjustment, or simply not waiting enough time to let the Alde heat.

I would also try the shower “boost” setting which should stop the glycol from circulating which allows concentrated heated glycol to heat the water.

You have the Flow - as I remember there were reports of initial fluctuation in temperature out of the faucet.

That foul smell suggests that the Alde and Flow were not completely emptied with winterization.

geoB

Sharon et al,

Thanks immensely for the comprehensive commentary. I've added some notes from this end. At a minimum I discovered I don't know how to change the hot/cold mix, let alone that it was adjustable. Please tell me more!

'Alde is set to “Therm"': yes

'...water temp = starting with very cold water, cold ambient temp...': Could have been a factor. Monday overnight low was 26°. Today, however, with ambient temp at home of ~74°, water temp at galley sink is only 92°

'...thermostatic mixing valve needs adjustment...': I see what might be a mixing valve on the bulkhead below the refrigerator. There is a red cap with "Alde" in white lettering. The cap seems to be loose - there's no resistance when I turn it. If that is the mixing valve how can the mix be changed? I found nothing about changing the mix in the Tab manual.

'...not waiting enough time...': I doubt this was a problem - the low temperature was noted Wednesday morning from a hookup on Monday evening.

'...try the shower “boost” setting...': I did try that but it must time out. No effect on water temp was noted.

'That foul smell suggests that the Alde and Flow were not completely emptied with winterization.': I accept that and appreciate learning more about the Alde system's requirements.

George

pthomas745

What you are describing with the "red cap with Alde" is the "Thermostatic Mixing Valve".

The link above has some more pointers and help, but this is the basic information on how to adjust it, where it says "temperature adjustment."  Some owners have been able to use the red cap to turn the adjusting screw, but others say an actual wrench does a better job.  Use care on the soft brass of the screw.

 

geoB

@pthomas745

Thanks! I'm always reluctant to pry anything off without instructions.

g

geoB

Unfortunately, the mixing valve is all the way counterclockwise - 93° looks to be about the best we can get at the sink. I haven't tested the shower, but that's got to be about the same.

Denny16

What are your Nautilus valve settings?  The Alde bypass valve is the red valve handle in the middle of the panel.  Also on the Alde control panel (directions are in your Alde manual) you can go into maintenance mode and check the glycol and water temp readings.  This will tell you if the Alde is heating up the glycol properly.  Next, check your glycol fluid reservoir level, it should be between the high and low marks.  This is located next to the passenger side port hole in the dinette area.
 Cheers 

geoB

Nautilus is City Water to Fixtures. Glycol is smack dab in the middle. Glycol setting is OK per Sharon, temp while camped was ~160°

Denny16

The red Alde bypass is a water valve, not glycol.  It controls water to the hot water tanks.  The red handle is set vertical to allow water to go to the Alde system to heat the water.  The only remaining issue is the hot water safety mixing valve, which is either stuck and not mixing, or is set too low.  You remove the red cap on the mixing valve, and turn the knob upside down to use it as a wrench to adjust the valve.  See the instructions posted above.
 Cheers 

geoB

I did not know that the red valve in Nautilus is also known as the Alde bypass valve. In the City Water to Fixtures setting the red valve points up.

[Deleted User]

Check this out

https://tab-rv.vanillacommunity.com/discussion/14924/2022-tab-400-mixer-valve#latest

Sharon_is_SAM

@geoB If you are on shorepower at home, make sure your Alde electric selection is “2 KW”.  You need at least a 16A breaker, so if plugged into a 15A breaker, make sure everything else in the TaB is turned off.  Then hit the boost and then after 20 min, check the water temp at the panel.  Just know, you may trip a house breaker.  The water temp at the tap will not  match the boiler temp due to mixing.

You may want to try it on propane.

[Deleted User]

I have mine all the way counterclockwise (screwed all the way out if you have the new style mixer valve with red cap) and the temp was WAY hot like over 120 degrees. I forgot to look at the thermostat temp once it got fully hot. If you put it on max hot setting you will use less hot water so I like mine maxed out. 

geoB

@Sharon_is_SAM

"...water temp at the panel...": Which panel - the Alde control panel by the door or the Nautilus panel? I have observed that the reading in the Alde control panel, Services, Water temp is different from the tap. What is the expected difference between control panel temp and measured temp? (I'm using a digital quick read thermometer I use in bread baking.)

Sharon_is_SAM

Water temp at the Alde control panel within “Services”.  Not sure off hand, but it seems that @ScottG measured the temps once.

geoB

I'll run your suggested test tomorrow morning and report back. Thanks for all your help.

Sharon_is_SAM

For a faster heat up use the electric and propane.  The propane delivers 5 KW and will get you to top temp faster.

Denny16

The Alde Service menu shows the water temp in the hot water tank.  The tap temp. is lower as the hot water mixing valve under the bunk, adds cold water to the hot water from the tank, to give you a lower useable temp and make the hot water run or last longer. 

 In Boost shower mode, you get hot water faster, as the Alde heating circulation pump is shut off, and all the glycol heat is going to the hot water tank and the Flo pre-heating tank.  With the proper setting on the hot water mixing valve, you should get almost continuous hot water when in the shower boost mode.  

Cheers 

[Deleted User]

Oh yes, Denny you are right about that! I think I saw like 138 or 140 on the service menu and that would send you to the hospital with burns. 

ScottG

Sharon_is_SAM said:

Water temp at the Alde control panel within “Services”.  Not sure off hand, but it seems that @ScottG measured the temps once.

I did, but with the caveat that I have the analog panel and no mixing valve. IIRC, HW tap temp was around 135F on "heat and hot water" and just north of 150F on "hot water only." These values were consistent with Alde's published values.

While I am just as happy to not have a pesky mixing valve, I can see why nuCamp started installing them. 

geoB

Sharon_is_SAM

Water temp testing:

Initial conditions: City water, shore power, propane on at controller

Time	Service temp	Cold tap	Hot tap	Boost
9:50	127	72.1	90.1	No
9:54	-	-	-	On
10:03	145	72.5	94.2	On

Note: each tap temperature was taken after discarding >= 12 cups of water

I expected hot water to be greater than 94°

Edit: While running the hot water tap for the boosted test I heard some "blooping" that did not occur when boost was off.

Denny16

If you want the water hotter at the tap, you need to adjust the safety mixing valve.  That said, 94F water is plenty hot for washing up and a shower.  Hot water at the taps is not instant, and I use a pot to catch the odd 12-cups of water while it gets hot water to the tap.  You could also save this water in a plastic water jug.  We pour it in our Berkey to use as drinking/ cooking water.
 Cheers 

geoB

Denny16

The mixing valve is maxed already. I would be far happier at >=100°; last year we had hotter water.

edit: Rheem says "...most dermatologists recommend keeping the temperature at an average of 98°F (37°C) to 101°F (38.3°C) or no more than 105 °F (41°C)"

Denny16

OK, I am a wimp, 100F is too hot for me.  If you have not changed the valve setting from last year, then you are having an issue with the mixing valve.  I would have it checked out by a good dealer service department, it may be a warranty fix for you.  There have been some reports of this valve failing.
 Cheers 

geoB

Sharon_is_SAM
Do you agree with Denny16 regarding a possible mixing valve issue? If so, I'd like to get the six to eight week process started as soon as I can.

geoB

Did a repeat of the test described above with the mixing valve rotated clockwise 4 complete turns. Hot water tap had only cold water. Returned to the full counterclockwise position and the same result - cold water only at the hot water tap. Appointment made for 3 weeks out for trailer service on extended warranty. Oh joy!

Sharon_is_SAM

@geoB - you are getting too much cold water into the mix.  Just to confirm, is both the Flow and Alde pump setting the same?  

geoB

Afraid I don't know the Flow setting; where does one find it? But the question is now moot. I've made a service appointment with the dealer and put the trailer back in storage. The good thing is we got an extended warranty when we got the trailer last year. So even though I'm game to try to fix almost anything, I've turned the issue over to the dealer. With luck it'll be usable again in maybe six weeks.

Sharon_is_SAM

I may be mistaken.  According to the Owners Manual, the flow does not have a separate control - never mind😊