Lonely 2 pipe radiator

jlo1029

I have a 1200sq ft house with 7 radiators on 1 pipe steam. All are 1 pipe radiators... Except for this one which has 2 pipes. I think it was added late, as the pipe to it is copper (all others are iron). The "second pipe" is in iron and has a main vent on it before it goes back into the main. The copper pipe gets hot (and makes annoying expansion noises) but the iron pipe does not. What's up with my misfit radiator? It heats fine, just rattles. The rest of my system is very quiet.

Thanks for any help with this mystery! The folks here are great and I now have a working sight glass, LWCO, insulated mains, and a big mouth main vent!

Fred

Both of those pipes look like iron. Does it transition from copper to iron below the floor? In any case, that is a large radiator and the supply pipe may not have been large enough to carry steam and allow condensate to return at the same time, hence the installation of the return pipe. Which of those two pipes is the supply pipe. I have to guess the smaller pipe cut into the baseboard since the radiator seems to pitch to the other side. If the supply is, indeed, the one cut into the baseboard, it does look too small to carry steam and condensate. Having said that, if the small pipe is the supply, it looks like the vent is on the wrong side of the radiator. Do both pipes go back into the main or does one of them drop into a wet return? Both should not be tied into the main.

jlo1029

The one on the left comes from the main and is copper in the basement. The one on the right goes into the wet return and is iron. The left side of the radiator gets hot first, so that's the supply pipe. I actually don't think I've ever felt the pipe on the right get hot... House gets warm before that!
It's pictched down on the right. Left side higher.
I wonder if it's supposed to drain left to right but actually isn't?

Fred

If the one on the left is the supply, then yes, the radiator should pitch down towards the one on the right, that goes to the wet return. Is the copper pipe in the basement, off of the main, smaller than the pipe coming into the boiler, on the left side?

Jamie Hall

And if it goes into a wet return, then yes it has to have a vent on it -- either on the pipe or the radiator. That vent looks set a little high -- but if it works, don't fix it.

The copper will expand and make all sorts of interesting (?) noises. You may be able to get it to relax a little by making sure that it isn't touching anything, or by slipping a shim from a plastic milk bottle or some such in where it does touch.

jlo1029

> @Fred said:
> If the one on the left is the supply, then yes, the radiator should pitch down towards the one on the right, that goes to the wet return. Is the copper pipe in the basement, off of the main, smaller than the pipe coming into the boiler, on the left side?

Marginally smaller. Should I worry that the "return" pipe never gets warm? (How can I tell that the condensate isn't going right back into the main?)

Fred

@jlo1029 said: Marginally smaller. Should I worry that the "return" pipe never gets warm? (How can I tell that the condensate isn't going right back into the main?)

As long as the radiator is pitched towards that return pipe (return side is lower than the supply side) you should be fine. The return side should be cooler than the steam side, just warm because it is only carrying condensate. I keep looking at you picture and it is deceiving. It really looks like the left side is lower than the right. BTW, if condensate were going back down the supply side, that's OK. That is how all your single pipe radiators function. I have to believe that they added the return pipe because the supply pipe was too small to carry both steam and condensate at the same time.

jlo1029

> As long as the radiator is pitched towards that return pipe (return side is lower than the supply side) you should be fine. The return side should be cooler than the steam side, just warm because it is only carrying condensate. I keep looking at you picture and it is deceiving. It really looks like the left side is lower than the right.

I must have not been holding the phone level... Using a level, it's definitely pitched towards the right.

jlo1029

> The copper will expand and make all sorts of interesting (?) noises. You may be able to get it to relax a little by making sure that it isn't touching anything, or by slipping a shim from a plastic milk bottle or some such in where it does touch.

It's not touching anything to shim but I did this with my ticking riser pipe in another room and the problem was fixed 100%!

Fred

BTW, if condensate were going back down the supply side, that's OK. That is how all your single pipe radiators function. I have to believe that they added the return pipe because the supply pipe was too small to carry both steam and condensate at the same time.