Alde 3020 Tank Draining

JabGopher

*Edit for clarity: Below is commentary and observations for a 2021 Tab 320 with the Nautilus panel. Even so, later revisions may differ. YMMV*


Hi all,

After our last trip where we were hooked up to city water (and on an empty FW tank), we opened the low point drains (only) to drain the plumbing. I opened the taps at the kitchen sink on both cold, then hot to allow better draining.

When we reached home about 2.5hrs later, I opened the yellow Alde valve and much to my surprise, there was only a trickle of water coming out. I parked it in my mind to search this knowledgeable community at a later time.

Did the action of opening the hot water tap at the kitchen facilitate the draining of the hot water tank? I was fully unhooked from shore power and the water pump was not running when draining via low points.

I'm trying to think through this and if the hot water tap effectively "calls upon" the HW to come to the faucet (drawn from the HW tank), and rather the low point drain is open, that HW would simply be rerouted to the low point drain? Is this logic completely void if the pump wasn't on?

I certainly recall other times where I opened the low point drains and also the yellow Alde valve and there would be noticeable amounts of water coming from the clear Alde drain tube below. Could this be just that because I didn't open the taps, I saw more water drained from the Alde tank?

Thanks all.

4ncar

@JabGopher: your logic is not flawed! By opening the hot water tap you have essentially drained the hot water COIL(not a tank) in the Alde. Opening the yellow valve just insures that it is empty.

ScottG

I wouldn't be so sure... HW exits through the top of the Alde. Cold water enters through the bottom, but it looks like there is a check valve between the CW inlet and the cold water drain. If I've got this right, opening just the low point HW and CW drains will not drain the Alde (which normally holds 2.5-3 gallons of water.

I'm belaboring the point because I had a similar experience during one of my early winterizations. I had opened the low point drains first (thus relieving pressure on the system) and when I opened the the Alde drain (yellow flapper) nothing came out.

Since there is no way to visually confirm if the Alde is full or not, I was skeptical. I refilled/repressurized the plumbing (at which time I do not recall hearing the Alde refilling), opened the Alde drain first, and the expected amount of water drained out.

Again, without visual verification I can't be sure of what is happening, but I suspect that under certain conditions flow from the Alde drain is impeded and water remains in the unit.

Here's the discussion I posted at the time. 

JabGopher

Very interesting. I filled my FW tank today and bled the air on both systems but did not pay attention to see if I could hear the Alde filling up.

So I will repeat what I did the other day and re-pressurize and see if I can (a) notice minimal water draining from the Alde; and (b) see if I can hear the Alde filling up

Sharon_is_SAM

@JabGopher, Do you know how to tell if your Alde water tank is filled?

Also, if your plumbing is pressurized - either following a city water connection or following use of the water pump, we have found that the Alde will empty much faster if you drain the Alde tank first using the pressure relief valve.  Put a bucket under the Alde drain and tilt tongue up to drain more completely.  Then after the Alde is drained, open the hot and cold low point drains to drain the plumbing lines.

JabGopher

@Sharon_is_SAM

I believe so - once pressurized, i'll turn on the hot water in the faucet to bleed all the air out and that should mean the Alde water tank is full yes?

Also, I just finished draining just the yellow Alde valve first and marked the water level (~halfway up) on a 5-gal bucket.  This seems in line with expectations.

I'm reheating a new "batch" of water now and will repeat just the low point drains with buckets under both to see how much water I get and if an open faucet aids in that....then I'll check the yellow valve again to see how much water drains.

I think the amount and the temperature of the water coming out of the low point drains should give me a better indication as to if the Alde tank is in fact draining via low point with the hot-side faucet open.

Sharon_is_SAM

Yes, once the sputtering stops, the Alde tank is full.

JabGopher

Well, I can almost positively confirm that based on amount and temperature of the water draining through the blue low point drain, the Alde hot water tank is draining there. I even felt the blue plastic tubing running underneath the cushions and felt the warm water routing through to the low point drain (from the yellow valve, to the flex tubing through to the black Alde bypass, back down to the blue tubing that leads to the low point drain site.

The faucet being in the ON or OFF position had no effect. The yellow valve was shut (parallel to the floor) the whole time.

That being said, if the point was to allow the water to cool down before draining, you can't just drain your plumbing without also draining the hot water in the Alde.

It's either that, or my unit is a one-off and a check valve somewhere has gone wrong.

Sharon_is_SAM

Did you see this plumbing schematic?  Pre 2021.

https://us.v-cdn.net/5021717/uploads/editor/dl/qfgpl3lmyfbz.pdf

Sharon_is_SAM

@JabGopher - you do realize that we want a 2021 320 plumbing schematic with your name on it😜

JabGopher

Hah! I'm not confident in my ham fisted non-scientific experimentation to be able to produce such an authoritative reference guide. I will, however reach out to NuCamp to confirm that it is expected draining behavior ... and that the blue and red pipes are merely for decoration when it comes to the low point drains.

ScottG

Good sleuthing, @JabGopher! When I had questionable Alde drainage back in 2016 I also heated the water so I could be sure the Alde was draining. However, I never tested it to see if it would actually drain from the CW (blue) low point drain.

There is (at least in my 2015) a device that looks like a check valve just upstream from that yellow flapper valve. When I winterize for this season, I'm going to duplicate your test and see if I get the same results.

JabGopher

Quick update with a response from nucamp with (edits for context):

"This is completely normal (the fact that the blue low point drain, drains the Alde). The (yellow) relief is there in case the Alde builds up too much pressure ... the relief can be used to drain the Alde in the event that you do not want to completely drain the water system."

ScottG

Thanks for the update @JabGopher. I'm still going to test mine using your method as I am not always trustworthy of what I am told--particularly where model configurations have changed a bit over the years. I'll report back what I find.

Here's a photo of a typical plastic check valve, and a photo of pre-Nautilus T@B plumbing with the suspected check valve on the Alde CW inlet circled.



 

Bayliss

Interesting discussion, @ScottG and @JabGopher.

The comment from nuCamp is consistent with @JabGopher's test, but it's questionable in my mind.  But, there are differences in the plumbing configurations, including adding the Nautilus to the equation, so who knows.

IF the connection circled in the photo above is in fact a check valve, then I would think that would stop the water from flowing backward toward the low point cold water drain.  Also, it would seem that the Alde hot water Safety/Drain valve would stop the flow of the water (without being manually lifted), unless it reaches a certain amount of pressure in the Alde tank, which would automatically open that valve to relieve the pressure.  I have not found anything that specifically states what amount of pressure will automatically open that valve.  I have seen it noted on this forum at least once that it is 65 psi, but I do not know the basis of that information.  The spec label on my Alde 3020 HE indicates that the “maximum domestic hot water pressure” is 44 PSI.

Finally, although it may be different with the Nautilus system, the Alde manual for the 3020 (which I have in my 2019 320 S) instructs to use the Safety/Drain valve to drain the tank:

1.      Switch off the fresh water pump.

2.      Open all water taps.

3.      Open the safety/drain valve by lifting the yellow lever.

4.      The hot water tank in the heating system will now drain directly below the vehicle through the safety/drain valve hose.  Check that all the water is emptied out (about 2-3 gallons/7-10 liters).  Leave the valve in the open position until the next time the boiler is used.  [NOTE:  About the only way to confirm that the tank has emptied is to measure the amount that drained.  According to the Alde manual, my 3020 tank holds 2.1 gallons of water.]

Denny16

That is the same procedure I use in our 2018 TaB 400, drain the hot water tank via the safety valve and leave it open.
cheers

4ncar

It just seems to me that there is more then one way to skin this cat!😺

ScottG

Maybe. Maybe not. Problem is with no visual way to confirm that your Alde is truly empty, come spring you risk having a very expensive paperweight under your bed.

As a matter of habit, I also flip the Alde drain first, after turning off the CW supply to the Alde. That way I can be certain that whatever comes out is coming from the Alde. YMMV.

Sharon_is_SAM

@JabGopher - I think what you are describing is unique to units with the Nautilus.  The pre-2021 units have a cold water line check valve that prevents backward flow to the cold water drain.  The check valve would need to fail for hot water to drain through the cold water drain.  

The other pre-2021 scenario is if the Alde bypass valve is opened and water exited the Alde via the hot water outlet, then it could conceivably drain hot water from the cold water drain.

So, I believe the pre-2021 hot and cold water low point drains are to drain the plumbing lines, not the Alde tank.  We will be taking the TaB out once more this season and I will try to remember to check this out.

@ScottG - I have been looking at your plumbing diagram.  You have an extra drain labeled as a Safety Relief drain on the hot water line off the Alde.  Now there is only 1 Alde Safety/Drain valve off the Alde cold water Line.

ScottG

This is the thing I labelled as the "HW pressure relief drain" on the schematic. I was admittedly guessing, but the drain line running from it and out the bottom of the camper made it seem like it was a pretty good guess. Is that component no longer there? 

Ultimately my goal was to include every component in the system, even if their functions were not 100% clear.

On a related note, I now believe the component labelled "Glycol pressure relief drain" is actually the Alde's automatic air bleeder. 

Sharon_is_SAM

The vented valve that comes off the Alde hot water outlet is still there.  The clear hose attached to it is the Bleed Hose.  I think it just acts as an overflow for water.   When I saw “pressure relief” I thought “Safety/Drain” valve.  

So, your labeled Alde hot water tank drain on the cold line is really the Alde Safety/Drain valve and your labeled Safety Relief drain on the hot line is the Alde Automatic Check Valve/Bleed hose assembly.  

Semantics!  @ScottG - wish we had more schematics like yours.  I refer to it frequently.  

JabGopher

Sharon_is_SAM said:

@JabGopher - I think what you are describing is unique to units with the Nautilus.  The pre-2021 units have a cold water line check valve that prevents backward flow to the cold water drain.  The check valve would need to fail for hot water to drain through the cold water drain.  

Yup, certainly seems so. I've added a quick clarifying point on the OP.

ScottG

Sharon_is_SAM said:

...

Semantics!  @ScottG - wish we had more schematics like yours.  I refer to it frequently.  

I'd say it's more than semantics--back when I made that schematic I just wasn't sure exactly sure what some of those doo-dads were! I probably should go in and make a few edits.

Sharon_is_SAM

@ScottG - we need a Nautilus diagram (hint, hint).  What program did you use for that schematic?

ScottG

You won't get one of those from me unless I get a 2021 to dissect, and I have no desire to trade in my nice basic 2015 without all the "improvements" added in later years.  ;-)

The schematic was drawn from scratch using LView Pro, a basic painting/drawing application I picked up for free a very long time. I like my software as simple as my T@B!  :-)

Sharon_is_SAM

OK, I will look for a volunteer🙏

ScottG

Ultimately, my guess is that the schematic for the Nautilus wouldn't look all that different. It seems to me the Nautilus is just the same basic collection of valves corralled into a fancy box and operated from outside the camper. Twist the right valves at the right time and the functionality is pretty much the same!

Sharon_is_SAM

Except it sounds like the low point drain, drains the Alde!

Verna

I volunteer, @Sharon_is_SAM, after I get mine. At that time, tell me what photos you want and I’ll do it. 

Sharon_is_SAM

Okay Verna and I will sharpen my pencils!

ScottG

Sharon_is_SAM said:

Except it sounds like the low point drain, drains the Alde!

Yep. Hence the qualifiers "...wouldn't look all that different" and "...pretty much the same."  ;-)