This is a picture of the connections to an old hot water heater. I opened the wall to reconfigure something.

As shown you can see the 3/4" cold supply going into the HWH, the 1/2" hot coming out of the HWH. Next to the 1/2" hot copper line there is a much smaller line I don't know where it leads to, the tip of it has been crimped shut a bit.



What is it? Is it some condensation line? Or it's a discharge line for a T&P valve? Where would the other end lead to?



Edited 1 times.

? a recirculation line for the HW ?

Taco used to make very small LOW VELOCITY 'package' pumps for that purpose.

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"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638

Recirc return line?

Doesn't a recirc line need a pump? I don't see any pump or any piping that returns.

Could the tube have extended up for a swamp cooler on the roof?

Since you are in Florida, I'm guessing humidifier is out of the question

Regardless of what it WAS, it is crimped and soldered shut for a reason, and reason could be because it doesn't work any more.

If so, it would usually have a valve in the wall to control the flow.

not soldered shut. Just crimped - pinched.

many, many years ago MA allowed 3/8 soft copper for relief valve discharge piping.
mostly was done on water heaters located on upper floors in tenament buildings..

Not if the valve was eliminated during a water heater change out at some point, and the line was just left there

An evap cooler line would go UP to the roof, not down into the slab. Soldered or crimped the result is the same. It is a dead line so forget about it.

Original post doesn't state it goes into the slab. There could have been a hose bib at a lower wall location at one time, with the 3/8" tube running up to the roof.

YOu are clutching at straws. When the coolers came off a hose bibb tapping it was a "retrofit" and ALWAYS went up the outside of the house.

"Always" is not a good term to use, when the properties being discussed are the ones Sum buys(no offense Sum).

Being that the exterior wall, where the tubing in question is located, appears to have been opened up (cement board sheathing?) we have no idea if the tube is original or installed by a previous owner or what the purpose for it was. When Sum asks what it might have been for, game-on for any and all suggestions.

quote; When Sum asks what it might have been for, game-on for any and all suggestions.

No offense meant, but has Sum EVER asked a question and accepted the first answers to solve it"

of course I have accepted first answer to my question.

but what I think Steve meant was when it comes to my properties ESPECIALLY this one where the plumbing and electrical work can probably fill up a book on "DONTs" and trying to figure out the intentions of the previous owner by assuming there is a valid reason for it is a hit and miss.

This will be the eighteenth answer to this string, and we still do not know any more about that small line than when we started.

It's very common in old S. FL. houses to see 3/8 soft copper used for the p&t drain line

? 3/8 OD ?

BOOOOM, or was that thunder ?

==============================================

"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638

IT was also done here in the 50s. They ran the 3/8" copper up next to the flue onto the roof. One customer ran his into his flue, figuring that if it discharged the water would extinguish the flame, the heater would cool down, and prevent any problems, assuming the gas valve actually shut off and was not stuck in the open position.

The thing I haven't heard mentioned is a discontinued supply for the fridge or an ice-maker or even a pool filler. Without the other end you may never know....