Basic Radiator Questions (Noise!)

here24

Hi there!

My radiator has been making awful sounds at night for several months. At 4am and/or 6:30am there will be about a minute of super harsh metallic very loud sounds — sort of a banging, but sort of a varied clanging. The other sounds it makes, during the day, are much quieter, and I can handle those okay. Is this water hammer? (Back in November/December, there was awful awful day-and-night water hammer that made a more regular hammering sound, that thankfully did get fixed.)

I'm a renter trying to better self-advocate with my building manager. I get the sense that he thinks there's nothing to be done, and I guess I'm curious if that's true; I haven't had a good night of sleep in months. I'd like to be able to ask about specific things (like, bleeding the radiator? or the pitching it correctly? — though I don't really understand what those mean), but I'm pretty confused about even the basics. Like, I think this is a steam system? Maybe a two-pipe system? With a TRV + inlet on the bottom left? Is that an air vent on the right, in the middle? And a steam trap outlet on the bottom right? (Is it normal for there to be both?) Which way should this be pitched? Etc. etc. I've been reading things on the internet but having trouble understanding in the context of my situation. I'd love to have a better sense of what I'm talking about and what to be asking for.

Several pictures are attached. This is on the third/top floor.

Would be grateful for any help or suggestions!

Grallert

Can you identify where the banging is coming from? Is it at the radiator or under the floor?

ethicalpaul

There's probably nothing you can do. Somewhere there is water pooling in the steam supply pipe (the one on the left). It is likely under the floor. The problem has to be solved by a steam professional hired by the building management. The pitch of the radiator is not going to affect this.

When the heat is likely reduced at night, and this allows that pooled condensate water to cool. Then when there is a call for heat in the early morning, the steam comes into contact with that cool water and it causes the steam to collapse which flings the water against the pipe, causing that sound.

Now that vent on this two pipe radiator is a sign that something is fouled up. And ironically, that might help you. You could rotate the vent so that it's upside down and see if that makes the sound stop. If it does, it will also probably prevent steam from entering the radiator so it may make your room cold.

You could also try adjusting the TRV on the left side, turning it all the way down, but I don't hold out hope it will help much.

BobC

That air valve looks new, did someone install that to avoid fixing the trap?

Bob

Jamie Hall

That WAS a two pipe steam system. It is now a bodge job. The original concept was that the steam was supplied by a boiler, at rather low pressure, and arrived at your radiator, where it condensed and heated the room. The air was released from the radiator through the trap on the right-hand side of your radiator and made its way back to the boiler Very simple. Very quiet.

I agree that it is likely the shiny silver vent was put on because the trap failed. They do if the system isn't maintained. This means that any condensate probably has to try to make its way back to the boiler through the inlet. Now someone decided to put a TRV on the inlet. It may or may not be a correct TRV from a steam system — but unless it is a very unusual one, it is installed in such a way as to almost guarantee to restrict that condensate flow. This will trap condensate in the radiator, and when the TRV opens, it will make objectionable noises.

As a renter there really isn't all that much one can do about it all. Try to get your building manager to get a steam heating person in to examine the whole system; it is unlikely that your installation is the only problem with the system…

here24

Thanks, all — this is very helpful! It's nice to start to understand what's going on.

(And the air valve was indeed replaced earlier this fall, when I complained about the initial loud hammering sound. There had been an older one there prior. All the radiators in my unit have this setup.)

dabrakeman

You could try to see if your building manager would be wiling to get on this forum and ask a few questions himself. No hurt in asking.