What kind of radiators do I have, and how do I fix them?

November 5, 2007 10:33 AM

What kind of radiators are in my house, and how do I fix them? They're broke, it's cold, and the radiators are so old I can't find any information about them on Google! Pictures here.

I live in an old rowhouse. It has oil heat and uses radiators, really, really old radiators. I've been here for a few years, and the heating has gotten progressively worse--some radiators remain cold all winter, others are sporadic in whether or not they turn on.

I have talked with my landlady, but I don't think she knows what kind of radiators they are any more than we do. She said two years ago the oil company cleaned the boiler and bled it, whatever that means (though from what I remember the radiators weren't any warmer, and a few remained completely broken). She suggested the individual radiators needed bleeding, but I don't think our radiators are the bleedin' kind. It's my understanding that bleeding individual radiators requires a key, as well as a place to put the key. We don't have key-holes on our radiators, just things that look like they could be pressure valves but don't release even when fully unscrewed. There are also these things attached to the floor.

Can anyone tell us what these things are and how we take care of them? I would like to have a better idea of their operation so we don't just call for the oil company again--I get the feeling they weren't quite sure what kind of radiators we had either and just threw my landlady a bunch of BS when they were "fixing" it a two years ago.

posted by schroedinger to home & garden (20 comments total)

Egad man. Tell your landlady to get off her rear end and fix the freaking radiators, or you are filing a complaint with the city. This is her job, not yours.
posted by 4ster at 10:37 AM on November 5, 2007 [3 favorites]

I am not an expert, but you have steam radiators, which don't need to be bled. The pipe coming up from the floor is where the steam comes into the radiator; the excess pressure escapes from the silver release valve on the other side. If the valve by the floor is closed, the radiator will stay cold, so the first thing I'd check is to make sure that the valves by the pipe coming up from the floor are indeed open.
posted by MegoSteve at 10:40 AM on November 5, 2007

Ive got the same radiator in my apt. Except mine has a knob that you twist to turn the heat on. Looks like thats missing from yours. My knob is at the top of the pipe-thing in your img_0040.
posted by ElmerFishpaw at 10:44 AM on November 5, 2007

Well, if it comes to that I will. But I'd like to do it myself to improve my home repair skills. And if it isn't a simple job, I need to know the type of radiator and at least an idea of what's wrong with it to give her more details on why I'm calling a repair man instead of our crappy oil company and their poor excuse for repair work.

MegoSteve--how do I make sure they're open? Do I just take a wrench or screwdriver to whatever I can on the pipe coming up from the floor? How much do I unscrew it?
posted by schroedinger at 10:45 AM on November 5, 2007

Echoing Steve. That looks like a single pipe steam system, the steam comes up the pipe, condenses and then the water trickles down the same pipe. No bleeding necessary. And echoing 4ster, the heat doesn't work, get the landlady to fix it. Not your job.
posted by octothorpe at 10:46 AM on November 5, 2007

it probably has little to do with the radiators: the real question is whether it is a steam or hot water heating system i.e. what is the oil fired furnace heating up to send through the pipes into the radiator. If there is only one pipe going into the radiator it is steam (and those look like steam release valves, so I'll guess it's steam...)

bottom-line: you need to get your landlady call someone who can service a steam (or hot water) heating system. I'm not sure what 'bleeding' the system means if it's steam either...but there could be lots of problems, none of which you can do anything about.

hot-water and especially steam heating is a lot more sophisticated than hot-air and she needs to get someone who cly understands them. explain the problem to her and explain the problem to the people who come so they don't just fiddle with the furnace and leave.
posted by geos at 10:48 AM on November 5, 2007

schroedinger, if you don't know what you are doing, please don't play with steam. 212 degrees F is really freaking hot. Get the landlady to call a furnace repair person and don't let him leave until the heat works.
posted by octothorpe at 10:49 AM on November 5, 2007

Like Elmer just said, there should be a knob on top of your img_0040 that you turn. Does that whole round thing turn?

Whatever you do, do not take a wrench to the nut there below... That's what's holding the valve (and radiator) to the pipe coming up from the floor.

My suggestion, if you are desperate enough to spend money, would be to call a plumber and not the oil company. He might have to replace those valves so you can open them and close them.
posted by MegoSteve at 10:50 AM on November 5, 2007 [1 favorite]

The thing attached to the floor is either the inlet or the outlet valve. I'm not sure how the UFO-on-a-stick thing works, but usually it's a screw thread inside the bulbous bit at the bottom. Tightening the valve will prevent as much water flowing through, which means you'll get less heat, obviously.

I've no idea what the silver cone things are. Usually a bleed screw/valve is at the highest point on the rad, because air floats, obviously.

I hesitate to hazard a guess at how long those rads have been in, but if it were in the UK, it would be at the earliest ~20 years old.

What could have happened is that the tiny little holes in the valves get clogged up with gunk, which obviously means less hot water. You can get a cleanser which will clean the gunk out, and an inhibitor which will help prevent it appearing in the first place.

But seeing as you are renting, tell your landlady that unless she gets you some heat in the winter, you're going to go round to her house every cold day, and sit in her living room, and soak up her warmth. Or you'll be cutting the rent check to the amount it costs you to get someone in to fix the problem.
posted by Rabulah at 10:51 AM on November 5, 2007

also, playing around with steam release valves while the furnace is on strikes me as a bad move: think pressure cooker.

it's unlikely you can do anything for whatever the problem is.

the oil company probably has some guy who knows how to fix steam systems, but it might not be the guy they send out if they don't know what the problem is, you need to make sure you communicate what the problem is and make sure they send someone who knows what to do...

(kind of like the 19th century version of problems with the cable guy)
posted by geos at 10:53 AM on November 5, 2007

Yep, single pipe, low pressure steam. I have the same thing in my house and I've had problems as well. Here's what I know:

Those bullet shaped things on the side are air vents that bleed air when steam fills the radiator. They need to be replaced periodically.

Steam systems do not need to be bled.

The thing on the floor is just a valve. I'm not sure if it allows you to adjust the flow or whether it's just on/off.

If steam radiators aren't properly sloped so that the condensate drains back down the pipe, they can fill up and work inefficiently.
posted by electroboy at 10:53 AM on November 5, 2007 [1 favorite]

This is a pretty good description of how a steam system works.
posted by electroboy at 10:54 AM on November 5, 2007

The valve where the pipe comes through the floor is the inlet valve. Make sure it is completely open. The little silver bullet is the relief valve; it lets the air out but closes the instant it senses steam.

The basic operating theory of steam radiators is this: steam rises from the boiler, pushes the air in the system out the relief valves. Relief valves close when they sense steam isntead of air, and the steam builds up in the radiators. As the steam lets off heat, it condenses, and runs back down the pipe if flowed up in, back to the boiler.

The relief valves may not be opening. The holes they thread into might be blocked. The radiators must be angled slightly back toward the pipe; check that, else the water don't flow back. Down in the boiler, the water could probalby use a recharge - drain it all out, put in a fresh charge of water.

Beyond that, your landlady needs to get a repairman out there.
posted by notsnot at 10:55 AM on November 5, 2007

If the system is really old, corrosion could have jammed the feed pipes.
posted by Steven C. Den Beste at 11:31 AM on November 5, 2007

It sounds as if steam isn't getting into the radiator at all. The simplest cause of that would be if the valve at the floor were closed. Does the pipe coming out of the floor, below the valve, feel warm at all?

Since the valve is missing its handle, it'll be difficult to turn that stem (the stick of the "ufo on a stick"). The best tool to grab that stem with would be a pipe wrench, but you'd have to be careful because it's conceivable that using a wrench would let you apply so much force to the stem that you'd break it. If you discover that the valve is already open (lefty-loosey) then the problem will be somewhere below -- maybe a closed valve in the basement, maybe a badly leaking pipe in the wall... who knows?

If you really want to pursue this yourself, start here.
posted by jon1270 at 12:30 PM on November 5, 2007

Also, a book.
posted by jon1270 at 12:35 PM on November 5, 2007

If your landlady seems overwhelmed by this task ask if you can just deal with it and send her the bill, not to exceed $250 or so. Call the company that services the boiler, supplies oil, or the plumber, and ask them to help.
posted by theora55 at 12:46 PM on November 5, 2007

Dicking around with the radiator isn't dangerous. The steam should be <1 psi, so there's no risk of explosion. The boiler on the other hand should be left to the professionals.
posted by electroboy at 12:47 PM on November 5, 2007

Oh hai, I have a NY State boiler certificate, was a building super for two 130 year old buildings 5 1/2 years here in NYC and know a lot about one pipe steam heat systems with radiators, like the one in the image.

You have a cast iron one pipe steam radiator. Vintage model, still very much in use. Possibly anything up to 80 years old.

A boiler boils water. It creates steam, which rises, goes up one pipe attached to the boiler and enters from that pipe into the radiators (which radiate heat) on the floors above. If heat is not wanted from that radiator, there is an on-off valve, which has a knob, located usually at the base of the radiator, where the radiator connects with the pipe full of steam coming up from the boiler. This is not a heat adjustment knob, it doesn't work halfway, letting in a little steam. It's either on or off. Knobs work like faucets, turning right closes the valve, turning left opens the valve. Mnemonic: "Righty tighty, left loosey".

If one doesn't have the correct wrench to remove the old, possibly rusted up, or rusted to the old pipe, valve...and rips the steam pipe, it can be a troublesome repair. Right tools are needed for this kind of repair, including pipe cutters, if necessary.

People often think the on-off valve can be slightly adjusted, so the radiator is less hot or more hot. Nope. It's either hot or not. When the on-off valve is turned only partly on it usually breaks and rusts up. This may stop any steam from coming into the radiator and there is often water damage coming out of the join, where the on-off valve connects with the steam pipe.

If an on-off valve is to be replaced, the heat MUST be turned off at the boiler first. This is because the steam can come straight out of the steam pipe and burn the living daylights out of the person near the pipe and/or the steam can enter the living space, soaking it extensively with water as the steam reconverts to water once it cools. An on-off valve needs to be measured for the diameter of the steam pipe coming up to connect with the radiator. An on-off valve for a cast iron radiator costs basically under $100 and then another $100 to remove the old and install a new one.

The silver penis looking thing on the end is a Hoffman Air Vent (it's a vent not a valve but commonly mis-labeled valve), probably a Hoffman 40. Basic info and image [pdf] from the Hoffman site. Usually less than $20 bucks in a hardware store. It gets clogged with paint or sediment (rust, mineral deposits in the water etc).

How the air vent works: the radiator fills with steam that comes up from the boiler. As the steam comes up from the boiler, there is air inside the cold radiator that needs to escape or the steam cannot enter the radiator. So the air vent lets the cool air out of the radiator. When the steam hits the mercury in the air vent, the mercury expands and blocks the steam from coming out the vent. The steam stays inside the radiator, heating up the cast iron.

As the radiator cools, the steam turns into water again, the air vent opens again, and the steam goes back down to the boiler via the same pipe it came up. This is why a radiator needs to be slightly angled so the water returns down that pipe from the radiator. Sometimes a slender shim, sliver of wood, is put under the back legs of a radiator to increase the angle, as buildings can sometimes shift/settle at an angle over the years. But if the radiator is shimmed at too severe an angle the pipe can break where it is joined with the on-off valve.

Once in a blue moon, a radiator may be disconnected from the on-off valve, to get out any sediment laying around at the bottom of the radiator. This is called "bleeding the radiator". "Bleeding" is not performed on a boiler.

The boiler is on an on-off cycle, depending on the temperature outside (regulated automatically by a thermostat connected with an outdoor thermometer). The boiler usually goes on and off a few times an hour, genrating steam as needed by the temperature outside.

Practical information for you here.

You may need a new Hoffman valve.

You may need a new on-off valve.

The radiator itself doesn't usually have anything in it to break but it may need to be cleaned out and possibly have shims under the back feet.

Do not do the repair yourself, unless you can turn off the boiler for the entire day, in case you rip the pipe, need to re-cut it, while removing the old on-off valve.

Online, short history of the boiler.

The boiler system may need repair or adjusting too.

Lost Art Of Steam Heating- Everything you ever wanted to know about steam heating in one easy-to-understand book. $39.95

Should you have the bucks, you might consider an elegant radiator upgrade, about 600 bucks plus shipping.
posted by nickyskye at 2:10 PM on November 5, 2007 [11 favorites]

Now that's an answer.
posted by Happy Dave at 6:23 AM on November 6, 2007