Alde Hose Size/Winter Use of T@B?

ScottG

Does anyone know the exact inside diameter o

f the large rubber hoses that carry the glycol to and from the convectors?

Can anyone suggest a standard fitting that would allow a brass valve or other device to connect securely to that hose?

I'm thinking the clever owners who have modified their T@Bs for use in winter might know this information.

Thanks!

Tabaz

Exactly 2 CM (whatever those are).

ChanW

er, 25/32"?

ChanW

Maybe you could persuade a 3/4"id barbed fitting to go in there...

Tabaz

Exactly 13/16 "

Tabaz

Scott - I have leftover pieces from my mod.  Would be happy to send one to you.  Just PM your address.

ScottG

Thanks, @Tabaz --PM sent.

I'd guessed around 20mm based on my rough external measurements. The fittings on Alde components all are listed at 22mm, presumably to give a good snug fit.

I'm hoping I can find something like what @ChanW suggested that will work similarly, but it apparently can't be copper as it won't play well with the aluminum elsewhere in the system. Brass might be an issue as well. Plastic would be inert but would have to have a higher heat tolerance than typical PVC.  

Tundra57

Nucamp uses lengths of aluminum pipe. They do use the heafty spring clamps from Alde tho. I used 3/4 fittings. Can you get 3/4 pex couplers?

ChanW

The PEX fittings I've used on my home have all been brass. Is the brass compatible with the Alde aluminum system?

I'd like to put another tee drain in. PEX fittings would sure be easy!

Tundra57 said:

Nucamp uses lengths of aluminum pipe. They do use the heafty spring clamps from Alde tho. I used 3/4 fittings. Can you get 3/4 pex couplers?

ScottG

My limited but growing understanding is that while it is not as bad as copper, brass should also be avoided in systems that have aluminum construction. Possible galvanic reactions can cause the aluminum to corrode. I'm not sure how much trouble one or two small fittings would be, but I'd rather not test it for something that will remain permanently in the system but only serve a purpose once every several years.

Both the Alde glycol jacket and the convectors appear to be aluminum.

Stainless steel components would be ok, as would those plastics that are tolerant of higher heat (provided they are compatible with propylene glycol).

Everything looks simple at first glance, but I sure see how the old phrase "the devil is in the details" was coined.  :-)  

ChanW

Ok, so you got me curious...

Plastic PEX fittings are made to handle temps up to 200°F

Edit: I'd think they be able to handle glycol, since it's common in hydronic systems. I'll see what Viega sez about it.

Further edit: Viega only says they're made for potable water... doesn't say anything about heating systems and glycol...

Here's one...

(Darn it. Vanilla will only put images in the middle of the page anymore!)

ScottG

That would probably do it provided you can get a snug enough fit on the 20mm hose. My untested impression is that 1" PEX fittings will be too big, but 3/4" might be a little too loose for comfort in a permanent system.

The thing I'm pondering (more details later) might work with the addition of a stock Alde drain tee. @ChanW, IIRC you acquired on of these at one point. Where did you get it? The new Alde/Truma web site shows parts but doesn't offer internet or phone sales.

tybladesmith

@ScottG, Alde listed 22mm ID and 21.4mm is close to 7/8" ID EDPM heater hose FWIIW. I did use a 1/2" x 3" NPT pipe nipple with a worm gear hose clamp to seal for a temporary connection.

For reference: 1/2" x3" NPT pipe nipple OD=.840", 21.4 mm=.843", 22mm=.866", 7/8" hose ID=.875" 

Alde catalog also references a brass valve and nipple. 

ChanW

@ScottG, I planned to get that tee, but haven't yet. Now if Alde isn't selling them, I might have to go with something in ¾" or ⅞", if there's anything like that...

I think with that relatively soft rubber hose, there are some options. Probably better to go with the larger ⅞", if possible.

I think another thing we need to keep in mind here, is the resistance created with each fitting on the Alde glycol circuit.

In designing hydronic radiant floor heating systems, the fittings need to be kept to a minimum, as each creates flow resistance that the circulation pump has to overcome.

It's likely though, that the Tab's system is so tiny that it's using a relatively oversized pump, so I'd guess it shouldn't be a problem.