How to clean out recessed convector ?

njhouse11

So I have a single pipe steam system and from what I can tell, recessed cast iron convector style radiators throughout the house (12 or 13). The only one that makes significant noise is in my bedroom and its on the second floor, back of the house. Consistently makes a gurgling sound like water is sloshing back and forth inside and will frequently bang in the middle of the night.

I suspect that the pipe is not well insulated within the back wall but I can't really tell that without ripping out the wall. I have corrected the pitch of the radiator as best as I can and it has made a slight improvement but not much in the grand scheme.

It sounds like it is clogged with minerals and buildup, either at the connection to the pipe, inside the rad itself, or likely both. There is no valve to turn on or off, I can only adjust the attached vent.

My question is, is cleaning this thing out a difficult task? Can I just unscrew this with a pipe wrench and wash it out or is there more involved ?

nicholas bonham-carter

It’s pretty unlikely to be full of minerals, as it has been in contact with only distilled water. Try slowing down the vent. Some convectors have only small diameter piping, and struggle with steam.—NBC

KC_Jones

Have you verified the valve is fully open? I would doubt you need to clean it out, there really isn't anything that should build up inside them. Dry steam is pretty pure and shouldn't have anything in it to sludge things up.

Gurgling means water is laying somewhere it shouldn't be, this could be pitch or a partially/fully closed valve.

Some pictures of your setup would help.

njhouse11

Here are some pictures of the radiator

https://imgur.com/a/DFbEpKe

KC_Jones

What does the piping under the floor look like? It's definitely been messed with by someone as I see copper piping which wouldn't be original. I suspect the possibility of incorrect piping holding water and causing issues. The copper makes me nervous as any steam man knows not to use that on steam carrying pipes, so what else didn't they know?

Also it appears it might have a Heat Timer Varivalve which are known to be very aggressive and possibly cause issues. Can you verify which vent you have there?

njhouse11

Wish I could tell you more about the piping under the floor but we only recently bought this house. Main part of the house was built in the 1930s and the addition where this lies was added sometime in the 70s. I can hear the pipes leading up to this banging a lot too, especially when the temp really drops down.

Yes that is a Varivalve. I can swap it out, any recommendations?

KC_Jones

Banging means water is laying somewhere and the steam is picking it up and slamming into the nearest fitting. The only way to fix that is to get all the pipe slopes and radiator/convector slopes right.

Slowing the venting on the convector might help, you can start with turning the adjustment down to it's minimum setting.

After that add to your list, find and examine all the piping for proper slope. Pictures will help.

Also as is said many times on this site, that aggressive valve on the convector could mean inadequate main venting in the basement.

njhouse11

Ok thanks. I suspect the basement venting may not be great, I have two mains that run in the basement, one towards the front and one towards the back, each about 25 ft long and they have a Gorton #1 on the end.

One plumber I talked to said that would be fine as I want all the air to vent at the rads to humidify the house, though he did not seem to be an expert. The recommendations on this forum seem to make a lot more sense.

I'll try turning down the vent and will eventually have to open up the wall.

KC_Jones

njhouse11 said:

One plumber I talked to said that would be fine as I want all the air to vent at the rads to humidify the house, though he did not seem to be an expert. The recommendations on this forum seem to make a lot more sense.

He really said that? The vent should never let steam out, only air. Common misconception, but still amazes me it's being said by professionals.

You want main venting in the basement and the rad venting at the rad, that's the simple way of putting it.

For 25' of main a Gorton #2 would do, but for my money a Barnes and Jones Big Mouth is a better choice. It's a bit more than you would need, but IMHO it's a better quality

BobC

Heatimer vents are bad news on convectors, you really should have a convector vent (Hoffman 41) on that, they vent very slowly and can help reduce the rate of condensation.

I would also consider Bigmouth vents on the steam mains instead of the Gorton #1's.

Bob

ethicalpaul

> He really said that? The vent should never let steam out, only air. Common misconception, but still amazes me it's being said by professionals.

Sounds like the plumber is talking about warm moist air being vented at the rads, not necessarily steam. But yes, sounds crazy either way.

njhouse11

Ok I'll throw a Hoffman on there and see if that helps.

njhouse11

Just wanted to provide an update and say that adding a Hoffman 41 to that radiator (and another problematic one with a crappy home depot vent) helped things out greatly. Much less banging and noise all around.