Whatsit? 3/8" copper from radiator

[Jm66208]

Doing a bath demo and about to remove the radiator. This radiator has a 3/8" copper line teeing off the return line, just below the trap. What is it, and will cutting & capping it temporarily affect the system? Thanks!

 

[Dana]

I'm not quite sure, but for purposes of guessing & puzzling, is this 2-pipe steam, or is it a hot water (pumped or gravity) system?

 

[Sponsor]

 

[Jm66208]

Two pipe steam. Tube is 3/8" soft copper. House was built in 20's. Wonder if this something that was added on. Tube follows baseboard, then disapears into wall. I dont see any signs of it in the basement. Haven't cheched the attic yet.

 

[Jm66208]

Also, are there modern replacements for a two pipe steam radiator, similar to the hydronic panel radiators?

 

[Jm66208]

Ah! Just figured it out. House has a third floor dormer with a radiator that i missed. This is the return line for that radiator. Kinda seems wierd they ran a supply line straight up from the basement, but hacked in the return. Wonder when soft copper came into existence? Also wierd...the attic radiator has a hoffman vent on it.

 

[Dana]

That makes some sense. The supply has to be sized for steam volume, the return only needs to return the condensate, which has much lower volume, so for a small radiator it can be pretty small stuff.

Does the attic radiator have both steam trap AND a vent?

 

[Jm66208]

Yes. Both trap & vent.

 

[Jm66208]

Just curious... could the return line be eliminated on justthis one radiator, and treat it as a single pipe radiator?

 

[Dana]

Not likely. With single-pipe the condensation runs back down the supply pipe, which puts constraints on the slop of the supply pipe, and where it's draining back to. The supply distribution plumbing in 2-pipe systems isn't designed for the necessary drain-back characteristics.

 

[Jm66208]

I was hoping it would work, asuming that some condensate forms in the supply line, and makes its way back to the boiler.

 

[Jm66208]

Ok, another question. Would it be possible to convert a two pipe steam system into a pumped hot water system? If so, would it require a new (different) boiler?
The reason i ask, is that with pumped hot water systems, its easier to remove the cast radiators and replace with hydronic panels in some situations.

 

[Dana]

In most cases it's possible to convert 2-pipe steam into a pumped hot water (hydronic) system. Whether or not your present boiler is suitable for/capable of running as a pressurized hydronic boiler depends on the model. Most modern residential steam boiler can be used that way, many or most antiques, not so much.