Tube Fin Radiator Help

puck8605

Hi - I have a small tube fin radiator in a bathroom that I'm renovating that makes a horrible knocking sound like someone is banging on the pipe with a hammer. I've tried several venting options but have not had any success.

I attached a few pictures of the radiator. Does anything look off? There appears to be a slight sag in the copper but not sure if that's enough to cause the knocking.

My system is single-pipe steam. I know tube fin radiators are not ideal, but I have three on the first floor that work fine and don't have knocking anywhere else in my house.

I appreciate the help.

Jamie Hall

My first thought would be to find out if that valve is really open all the way. Sometimes the closure disc comes adrift, or partly adrift, and impedes the flow of condensate.

puck8605

Jamie Hall said:

My first thought would be to find out if that valve is really open all the way. Sometimes the closure disc comes adrift, or partly adrift, and impedes the flow of condensate.

Thanks...I hadn't considered that. I should have noted that the valve doesn't fully close so I had to replace the vent with a plug to get it to stop knocking.

EBEBRATT-Ed

@puck8605

As you mentioned fin tube is not great on steam. My first suggestion would be to run a return line but I am guessing this is second floor so that may not be an option.

First thing is to check the valve as @Jamie Hall mentioned, Second would be to disconnect the copper line from the valve and see if you can pull up on the valve. Use a crowbar and a block of wood to "gently put a little bit of pressure on it. That pipe may have sagged when it was disconnected. If the valve moves up put a hose clamp or a riser clamp or a split ring hanger under the valve clamped to the pipe to hold it up.

Then I would suggest raising the baseboard enclosure up so instead of the pipe going straight in you have room for 2 45-degree elbows or even 1 45 and 1 street 45 to give the baseboard a little rise. Then with the enclosure level on the wall shim the fin tube to pitch back towards the valve.

The other option which may be the best option is to toss the fin tube and go back to a cast iron radiator.

puck8605

Thanks a lot for the info. I just pulled up on the valve and it moved more than I expected. Might be an easy fix. Going to test it out.

puck8605

No luck so far. I took the radiator off and the valve seems fine. I ran the boiler without the radiator on and the valve open and did hear a bang and it seemed to be gurgling. I assume there's an issue somewhere that's inaccessible.

I'm eventually transitioning to a radiant heat floor in that bathroom so it's not a huge long-term problem. May need to use a space heater in there this winter.

retiredguy

You can not use 3/4" copper tube radiation on a one pipe steam system. Replace the radiation with 1.25 or larger copper tube radiation. That 3/4" tube radiation is OK on hot water and for a short run on 2 pipe steam. Also, that increaser (reducer) should be replaced with an eccentric reducer or no reducer at all.