Proper Air Vent Installation

Steamhead (in transit)

to the lower tapping. The upper tapping where it now is located is for a hot-water rad vent.

You can drill out that plug and chase the threads with a 1/8" pipe tap. Take it slowly and lubricate well as Matt says and you should be OK.

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SteveJones

Proper Air Vent Installation (help!)

My home has a one pipe steam system. Two floors have steam radiators (main floor above the basement and the top floor). I recnently replaced all the air valves just to assure they were all in proper working condition. I still get a noisey / gurgling sound from only one spot in the house. This is a top floor radiator or the pipe leading to it. When I read some of the tips on this site, one of the things mensioned that could cause this was an improperly installed or improperly functioning air vent. It went on to say to check to see if the air vent is installed on a extension pipe. This one noisey radiator is the only radiator in the house that does have the air vent conected to an extension pipe, which connects it to the radiator. Coinsedence? I wonder if this could be the cause... Any ideas?? The tips on this site said to check to see if this was the case, but it said nothing more about it (IE is this always bad, what to do to correct it, etc) I believe it was connected in this way because without the extension pipe there is a part of the radiator itself that extends out a bit and would prevent you from screwing the air valve on with no extension. Any ideas / input is appreciated! Thanks in advance!

Matt Undy

The pipe could be holding water. The inside diameter of pipe that fits into the vent tapings on the radiator is so small that water tends to stick to the walls of the pipe and form a plug rather than run out the end. This can cause water to collect in the vent.

Vents have a tung that sticks out of the end of the inlet that encourages water to stick to it and drip off rather than form a plug. Depending on the configuration, you could try to emulate this in the pipe with a piece of thin copper wire, but by far the best option is to attach the vent directly to the radiator. There may be a vent with a longer nipple that is available from a heating supply that specializes in seam specialties. Is the obstruction actually part of the radiator? Attaching a picture could help here.

Also, if the piece that is attached is bigger than the taping and there is a reducer to adapt it to the radiator taping, unless the reducer is offset(which are rare and special for steam), the reducer will trap water and cause problems with steam hammer.


Matt

SteveJones

Proper Air Vent Installation

Thanks Matt. I attached a pic of a radiator similar to mine that I found on the Internet. It is similar but not my exact one. The top floor of my house is rented out as an apartment, so I don't have access to get in a tinker with this whenever I like.

You will see in the picture that this radiator has some sort of very large nut / plug on the top center. That's basically the same as mine. This big nut / plug is what gets in the way of allowing the vent to screw directly into the radiator. The extension is needed so the valve clears it as you screw it in. I doubt I could get that big plug off as it is old and probably frozen in there very well. It is needed anyway. I could look to see if there are other spots away from that big plug to screw in a vent, but I doubt it because they would have probably used it from the start. Or perhaps there is a spot for a valve but it may be plugged and the plug may be frozen in. Are there any tricks to freeing a stuck plug in a cast iron radiator? Can I heat it with a torch? I'd hate to crack or break it! How about drill a whole myself and tapping it? I have never drilled / tapped cast iron.

Is there a height specification as far as where the valve needs to be located? The current location is right at the top of the radiator. All the other radiators in my home have the valves mounted about half way up, and they work fine. In the attached picture you can see there looks like there might be a spot down lower on the radiator to mount a valve. Would a low mounting location like that work if mine has one like that?

Thanks for any input!

jim_110

vent

How large ,IE, # of sections w/h/l, is the rad in question. Does the vent spit water? Did you check if you has slope to the valve? Let us know.

SteveJones

Proper Air Vent Installation

The radiator has 15 sections. The other radiator upstairs is about the same size. They are both the largest radiators in the house. A little over the knee in height, about 7-8 inches deep, and about 3 feet long.

I just spoke with my tenant. She says the valve makes noises like there is water in it (a bubbly noise), but it does not "spit" water. She also looked at it for me per my request and there is another location on the radiator for a valve and it is plugged. This plug is in the same location as the valve on the other large radiator upstairs and I would not need an extension to connect the valve to this spot on the radiator. I'd really like to try to get a valve on there instead! I have not tried to take it out yet. She said the plug is a flathead screw driver type fitting (no nut for a wrench, etc). I think this plug may be a pain to get out since it is very old I am sure, is a flathead, and has been painted over.

Based on this, any suggestions? I may make a separate post just in regard to the best way to remove an old plug from a cast iron radiator. Will heat from a torch help, or will that risk cracking the radiator?

And could this air vent placement / location really make this radiator / the pipe to it make all this noise? It heats up OK but is just too noisey.

Thanks again all

Matt Undy

There are caviats to taping a CI radiator..i know it can be done. I know you want to lubricate the tap with water only because oil or grease will contaminate your boiler and make it foam. Could try to remove the plug. Could just drill and tap a new area, might be best best if careful cleaning of the slot combined with a screwdriver of the biggest size that will fit in the slot that is nice and new and sharp doesn't do it. Lean in on the end of the screwdriver..get one with a square shaft and put an adjustable wrench on it. Heat the radiator around the plug, try to keep the plug itself cool. The hole gets bigger as it is heated, if the plug stays cooler, the clearance gets bigger. Don't heat it too much, even a few hundred degrees helps a lot, no need to go to red hot. If it doesn't come out, drill and tap a new area, probably less trouble than trying to extract the plug. If you did want to try removing the plug, you could get a left hand bolt and nut and left hand tap from someplace like McMaster-Carr and tap the bolt in to the plug and use the wrench to extract it. For some reason there is a danger that an easy out can crack CI. Tap the plug left hand, thread in the bolt, tighten the nut up against the plug, and use the bolt to back it out.

You might want to make sure the nipple slopes down hill and try getting a piece of wire to hang out the end into the radiator before attempting the surgery. You may also want to find a good plumber with the feel for when something might be about to break to perform the surgery.

Anyone here know of a vent with a longer nipple or even a toung that would extend through the nipple?

Matt