Alde yellow drain valve

stevea · July 2023

I want to drain the Alde boiler on my 2023 T@B 400. The Alde manual says the yellow drain valve should be in thye UP position. Where is the Alde yellow drain valve on the 2023 model? I used to access this beneath the bed on my 2018 model. Does the COLD or HOT water drain valve now operate this as well? (those 2 valves on the undercarriage beneath Nautilus panel)

pthomas745 · July 2023

Under the driver's side bench, where the Alde is. The Yellow Flapper valve is still in the same place in the trailer that it has always been: down there next to the Alde. The difference with the Nautilus in the newer models isowners don't have to go in the Alde compartment any longer. So, the Yellow Flapper Valve is not readily apparent. The cold water side of the low point drains does drain part of the Alde , but to completely drain the Alde tank, you need to open the Yellow valve. Your 400 has a Yellow Valve on the Alde Flow tank, too, so open that one up also.

Edit: See Denny16's post below for the proper location for the Yellow Valves in the 400. They are not "below the driver's side bench!"

manyman297 · July 2023

What’s the verdict on using the low point drains to empty the Alde after a trip? Is that not good enough? I used to flip the yellow valves but stopped midway through last season. Wondering if that was a bad idea or not?

Denny16 · July 2023

There are two yellow pressure relief valves on a 2019-2023 TaB400. Both are under the rear bunk, between the Alde boiler and the back,of the Nautilus panel on the newer TaB400. You need to lift both to completely drain the Alde system of hot water. One is for the main Alde boiler the other for the Flow tank.

The hot water low point drains will drain the plumbing system and most of the hot water tanks on the Alde and Flo system, but to drain all the water for winterizing the trailer the yellow valves should be also opened.
cheers

Sharon_is_SAM · July 2023

@manyman297 - we had a recent discussion about draining the Alde tank - maybe last fall when everyone was winterizing. Alde manual says to drain it using the yellow valve and it drains via the cold water inlet.

bergger · July 2023

Yes as mentioned by @Denny16 simply opening the low point drains will not completely drain the Alde. You have to open the yellow pressure relief valves. I've tried both methods and definitely get more water out when I open the yellow valves.

ScottG · July 2023

It may depend in part on what model/year T@B you have. In my 320 either the yellow flapper valve or the CW low point drain will drain the Alde HW tank. (I used to think there was a check valve that prevented flow back to the CW drain, but that was incorrect.)

The cold water line is used for draining because cold water enters at the bottom of the Alde tank. The HW low point drain will not drain the Alde tank, because the hot water line exits at the top of the Alde tank.

I'm unsure if/how draining is affected by the Nautilus system, Alde Flow, or other component added to larger/newer models. YMMV.

stevea · July 2023

Thanks All, Denny16 is spot on. The HW and CW valves drain the plumbing only. The 2 yellow pressure relief valves must also be flipped to completely drain the Alde system. I got an additional gallon or two when yellow was opened. Good to know come Fall. Now a hinge is needed on that bed panel.

Denny16 · July 2023

ScottG is right, it depends on your year/model TaB. Prior to the Nautilus unit used on newer TaBs, opening the hot and cold low point drains, drained the Alde boiler, as it has an air vent check valve, and the hot water low point drain was connected to the low point drain on the Alde. The Tabs, 2018 and older, also do not have the Flow aux hot water tank, which only drains with the yellow pressure relief valve.

Whilst the new TaBs have some nice additions, the older TaBs are simpler to use and whilst they lack the refinements of the newer TaBs, sometimes simpler is better. On my 2018 TaB400 (no Flo) I can drain the hot water system, including the Alde with the Alde low point drain, I have three drains, cold, hot and the Alde water tank.

Cheers

Sharon_is_SAM · July 2023

“and the hot water low point drain was connected to the low point drain on the Alde.”

@Denny16 - the Alde drain via the yellow flapper valve is in line with the Alde cold water supply. The hot water low point drain only drains the hot water supply lines as the boiler hot water outlet exits from the top of the tank.

krsmes · July 2023

stevea said:

Now a hinge is needed on that bed panel.

I’ve been under that ALDE bed panel so much in the two+ years of owning the T@B that I don’t even screw it back down anymore

dsfdogs · July 2023

@krsmes yeah, no need to screw it down. I also added a D ring tie down to make it easier to grab and pull up on the board.

RTWCTS · July 2023

dsfdogs said:

... I also added a D ring tie down to make it easier to grab and pull up on the board.

Great idea @dsfdogs! I've added this to my hardware store list.

manyman297 · July 2023

@krsmes Yeah, I think I removed the screws the first week I owned it and never reinstalled them. They need to just make it an accessible hatch...even if the area just above those valves had a hinged lid that would make the process so much easier.

@Denny16 @bergger Is emptying the Alde something you guys do after every trip? I was doing that for the first year but this past season I stopped draining it and only drained the Alde using the yellow flaps when I winterize.

bergger · July 2023

I drain all the lines, the fresh tank and the Alde after every trip. I usually do it as part of my packing up procedure.

Denny16 · July 2023

ScottG is right, it depends on your year/model TaB. Prior to the Nautilus unit used on newer TaBs, opening the hot and cold low point drains, drained the Alde boiler, as it has an air vent check valve, and the hot water low point drain was connected to the low point drain on the Alde. The Tabs, 2018 and older, also do not have the Flow aux hot water tank, which only drains with the yellow pressure relief valve.

Whilst the new TaBs have some nice additions, the older TaBs are simpler to use and whilst they lack the refinements of the newer TaBs, sometimes simpler is better. On my 2018 TaB400 (no Flo) I can drain the hot water system, including the Alde with the Alde low point drain, I have three drains, cold, hot and the

GregChris · July 2023

You should check out the Alde boiler 'air gap' info. After several days of continuous use this air gap disappears. If you don't restore it you can crack the boiler tank.( Happened to someone I know. Very expensive fix ). If you drain the hot water system after each trip, this is likely to never happen.

Yoshi_TAB · July 2023

Hi, @GregChris,

How is it possible to crack the boiler tank by not restoring the air gap? The purpose of the yellow valve is for both draining and safety pressure relief. I suppose the yellow valve could fail. Without doing an analysis, I would think other parts (plastic tubes, clamp connection points, etc) of the system would fail by over pressure before the boiler tank would crack. I don't know about the Alde boiler, but most pressure vessels have some sort of rating to prevent bursting to avoid injury. The air cushion is noted in the manual as a Notice not either as a Warning (injury to people) or Caution (damage to equipment).

Just curious, how did they conclude your friends boiler cracked because of the lost air gap. I would think we would see many more boiler failures if that was the case as I guess not many people restore their air gap (I never do and have 2 years of heavy service).

manyman297 · July 2023

I'm also wondering the same about the boiler cracking. The yellow valves would release long before any kind of pressure would damage the boiler. I've had those yellow valves release on house pressure before (probably was around 70psi). Most reports of boilers cracking are usually due to bad welds on the tank.

GregChris · July 2023

This was covered at the Truma talk at Ucamp23. You have to ask the Truma reps at tech at the talk. They plainly stated, if the air gap is not maitained the tank will crack, and it's not a warranty issue. User error. It's also in the Alde manual.

Binghi · July 2023

I thought the air cushion was to reduce the air hammer effect when you turn on the hot water faucet. Doubt that an air hammer issue would crack the tank. If so, the tank is too delicate, and that’s on Truma. Moreover, at least on the 400 model, the yellow relief valves are too difficult to access to comply with the 10-day water release rule that Truma sets out in the Alde manual. I guess the access problem is on NuCamp. Bad combination for the consumer.

pthomas745 · July 2023

Apparently, the Truma rep went on and on for about 15 minutes about the "air cushion" at UCamp this year. If this was a common problem, we would have seen many more broken tanks pop up beyond the very few (unfortunate) cases we have seen of this. The comments on the FB pages are saying things such as "hot water expanding in the tank" can cause issues. All we want from Truma, really, is straight answers.

manyman297 · July 2023

@GregChris This is interesting and the first I've heard of this issue.

Yeah, the more I deal with the Alde the more I dislike it compared to "dumber" systems. They're really a demanding appliance and once you lump in all of the maintenance needed for a camper it just adds more and more layers to the entire maintenance experience. And in the end all I'm getting is a more quiet heater? Plenty of other systems out there offer "tankless" hot water for a lot less money.

GregChris · July 2023

Not an engineer! Just relaying the message. They did say you don't have to drain the tank, just pop the yellow valve for 10-15 sec, or open the low point hot side for a couple of minutes. It doesn't matter whose at fault if you or I have to pay the price.

bergger · July 2023

So far we've had no issues with our Alde but did have to go through the century/rhomar switch over. Love/hate is too strong to describe my relationship with our Alde. I'd say it is a love/dislike relationship. Love it for it's quiet and wonderful performance but hate it for it's complexity and that is seems when a problem happens it is more often than not a major problem that is hard and expensive to fix. Also, even though I have figured out how to do my own glycol changes I am not happy about having to do them on such a frequent schedule. Also just the possibility of a glycol leak or corrosion in a location that is nearly impossible to access kind of stinks too. I'd give up the quiet radiant heat for a ducted Truma Combi plus unit in a heart beat.

Anyway as far as the air cushion thing goes. Since it is recommended I always drain the unit after each trip or if it's over a week I will do the quick procedure to re-establish the air cushion. Yes a bit of a pain to open the compartment but still only takes a couple of minutes to do. Truma combi does not require that. Hint, hint NuCamp.

Binghi · July 2023

I used to labor under the 10-day water release rule. On the 5-week trip recently completed I didn’t open a yellow valve. No problems. I’ll empty the Alde tanks before our next trip in September, but I’m done digging under the bed platform every two weeks while on the road.

manyman297 · July 2023

@bergger Exactly my thoughts…let’s get a Truma Combi in these campers. They’re really quiet and are much more basic in principle than the Alde. The Alde is great in that you get a “blanket” of heat that envelopes the camper while a forced air system just kind of gets pumped in all around you. A big plus of the Truma is the simplicity of install. Yeah you have ducts to run but you aren’t snaking pipes around the camper.

This may just be me but while the Alde is quiet, when it kicks on it tends to wake me up as I can hear the exhaust fan winding up and the boiler igniting. Kinda annoying but it might just be me. And then there’s the fridge compressor that kicks on and wakes me up too…so it probably is just me.

bergger · July 2023

@manyman297 yes I agree with you on the noise when it is fired up and running. Especially when running on propane. I've got a truma vario heater in our truck topper camper and love it. A combi unit would be even better. If our Alde ever craps out I may see if I can remove it along with the convectors and have a combi unit installed.

AnOldUR · July 2023

GregChris said:

This was covered at the Truma talk at Ucamp23. You have to ask the Truma reps at tech at the talk. They plainly stated, if the air gap is not maitained the tank will crack, and it's not a warranty issue. User error. It's also in the Alde manual.

For some reason I overlooked this for three seasons of heavy use on our 2020 320S and never had the tank crack. Luck or is this over hyped?

After hearing the uCamp talk I thought maybe I should flip the yellow valve, so did it yesterday as prep before leaving on a trip today. After draining the fresh and hot water tanks I refilled and ran the hot water from the sink to be sure the tank was full. I then turned the pump off and depressurized the system by running kitchen faucet (hot and cold) until the water stopped. I then opened the outside shower hot water valve and a fair amount of water drained out of it and I heard gurgling in the area of the Alde. The low height of the outdoor shower has me thinking that it may partially drain the hot water tank and maintain the air gap?

In fairness, probably 95% of our hot water use is from the outdoor shower connection.

gulfarea · July 2023

I have had 2 T@B'S with the Alde, THERE WILL NOT BE A THIRD! Art

Mickerly · July 2023

You guys do realize no matter what kind of hot water system you have, you shouldn't be storing the trailer with water in it. When water is stagnate, bacterial begin to grow.

When you look at the number of trailers produced with the Alde world wide compared to the number of issues, there are few problems. When used as directed, it appears to have little problems. If you would prefer a different design, then change it; however, your preference doesn't mean the Alde system is bad. It's just not what you want.

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