Radiator vent questions - how to remove and select correct replacement?

Volldampf

Hello,

We have a single pipe steam system and a few of the vents on our radiators have problems.

The house has a total of five radiators, three are on the second floor, two bigger radiators on the first floor.

One vent is cracked and leaks steam out of that crack and another does not close and vents steam out of the intended opening, it usually closes when I slightly tap it with a screwdriver, so maybe that one just needs cleaning. The third one with an issue has just come off the radiator and I cannot screw it back in, so I suppose the thread in the radiator would need to be redone.

How do I safely unscrew the vents for cleaning or replacement? How much force can apply there and is there any trick? I tried one and it did not budge and I am afraid to snap off the threaded part.

What information is needed to select the correct replacement vent and what is a good make to get? Should I just replace them all while I am at it? Or just clean with a good vinegar bath to dissolve the crud?

Some of the existing vents are adjustable? How do I determine the proper setting? I think they should vent in a certain order, right? Upstairs after downstairs I imagine?

Thank you!

Hap_Hazzard

You'll find the answer to all your questions if you use the search engine. This subject has been discussed many times and there have been some really good posts from some of our pros and even hobbyists who got interested in the subject, including pictures and descriptions of the different types of vents available.

Briefly, the purpose of the vent is to allow the air in the radiator and supply pipe to escape so the steam can fill the radiator, so the longer the supply pipe, the faster the vent required.

To safely remove a vent you need a wrench that fits the brass fitting that screws into the radiator. Twisting the body of the vent can damage the vent. When re-installing a vent, use PTFE thread tape and be careful not to cross-thread it. 1/8" NPT has 27 threads per inch, which is pretty fine, and it's tapered, so it's very easy to cross-thread, especially when working in a tight place.

Volldampf

Thanks for the response and the advice on the removal. I've applied myself a bit more to the search and am finding some good, relevant posts.

Steamhead

Also make sure your steam-main vents are properly sized and working. If you measure the length and diameter of your steam mains and tell us what vents are on them, we can tell you if you need to do this.

Volldampf

Alright, I gathered some information here, I see two main pipes coming off the header. Both are 2 1/4 " outside diameter.

The main that feeds the two first floor radiators is 38 1/2 ' long and at the end is a vent. The vent is a Dole Quick Vent Air Valve

The other main feeds the three second floor radiators, it is 17 3/4 ' long before it turns upwards and disappears into the the 1st floor. Upstairs there is no exposed pipes, I do not see a vent there.

I also had success unscrewing the radiator vent that is cracked. It is the same as two other ones in the house and is a Dole Vari Vent No. 1A Air Valve. One of the other ones does not sometimes close properly and I need to give it a little tap with a screwdriver.

So certainly one, maybe two replacements needed here.

The two other vents are I think both Hoffman Specialty Mfg., one is a Ventor No. 40 and the other is the adjustable kind and is marked No. 1A.

The No. 40 is the one that I can not for the life of me get screwed into the radiator, I think it must have been just held on by paint, because it got knocked once and just fell off, it does not look broken off. I think the threads on that radiator would need to be redone, because I tried to screw the other vent that I took off into that one, and could not get it to screw in either, while the No. 40 went fine into the other radiator.

Thank you for any advice you can give me on what I should attack here, what needs replacing aside from the obviously broken vent, is it worth trying to clean the one that does not close or should I just replace it?

Is the main vent right?

Is it worth replacing all the vents with new ones? I never gave the guys much attention since until recently they seemed to work fine. But who knows, maybe it could all work much better!

Thanks!!!

BobC

Your existing main vent is much too small. The consensus is that you need 1ea Gorton #2 for each 20 ft of 2" main (2-3/8" OD). That means you need 2 #2's on the long main and one on the short one. These are large vents (about 7" needed above the pipe), they have a 1/2" male thread.

If you don't have that much room you can use 3ea Gorton #1's for each Gorton #1, these have a 3/4 male thread and a 1/2" female thread. You can mount multiple vents onto an antler that attatches to the top of the main.

Fix any piping problems before adding the vents.

You can try boiling your radiator vents in white vinegar for 20 minutes to see if that cleans them up. Running lime-away through them also works.

Bob

nicholas bonham-carter

Leaking (but non-cracked) air vents may indicate that your pressure is too high.
Put a 0-3psi low pressure gauge from valworx on your shopping list, so you can verify the pressure to be under 1.5 psi (basic function), or 6 ounces, (comfort and efficiency).
Have you had to add much makeup water, to make up for the steam leak?
You could put the Hoffman 1a vent on the end radiator on the second floor. This will compensate for the length of the riser going up the extra height of the upper floor. Put Hoffman 40's on the rest.
You will still need the Gorton main vents in the basement. Do not consider the cost of these important vents and gauges as an expense, but rather as an investment in your comfort.--NBC

JUGHNE

To get out painted on rad air vents, I use a very sharp pick tool to cut the paint at the threads. (almost like a dental tool, but cheaper.) A few drops of penetrating oil before and after paint removal may help.
The air vent male thread is brass and subject to damage. The rad of course is cast iron. You could buy a 4" long pipe nipple and a tee fitting. Screw the nipple tightly into the side of the Tee. Then check and clean the rad female threads with your tee handle/iron pipe tool. This will not risk the brass threads on a new vent. (just a one drop touch of oil on the pipe threads.)

If the iron pipe will not thread in then you resort to a 1/8" Pipe tap with 27 threads per inch--tapered. NOT bolt threads.
You only want to straighten up or clean existing threads, not remove any iron. Don't get oil into the radiator.

I would just get all new rad vents as Nicholas suggested above. Clean up the ones that you think might work and save for spares. Please keep us posted on results, there is more advice available here.

Volldampf

Thank you All for the great advice!

I managed to get all vents out from the radiators, nice and gently applied force did it. They all went for a nice, hot vinegar bath and will go back for now, while I get suggested replacements.

Question about that, I took another look at the piping and its quite different from what I had thought:

The longer pipe goes from the header, feeds one downstairs radiator (dining) and one upstairs radiator (bedroom 1), then continues on to the main vent and then turns down and returns to the boiler piping.

The other pipe goes from the header across the ceiling to the opposing wall where it splits in a T arrangement, to the right, it feeds one radiator on the second floor (bedroom 2) and one on the first floor (kitchen). To the left, it goes up to the third radiator on the second floor (bath).

Past experience is that bedroom 1 gets warm last. Would that be the candidate for the Hoffman 1A then?

How about the other radiators? What vents would you recommend, does the Hoffman 40 recommendation still stand, given the different arrangement of the radiators?

I will certainly follow the recommendation of the two Gorton #2s to replace the existing main vent, there is space, but I need some pipe arrangement that allows the two vents, currently its just that one small vent screwed in there.

I am not sure about other main's venting? I do not see any big vent like on the other side. Could it be that there is none?

Nicholas, thanks for the pressure gauge suggestion, added to shopping list!

Bio

I use Hoffman40s and very happy with them, compared to the vents sold at big box stores are made of plastic inside, as said before you want to use G2s to remove all air from mains this way you create a steam manifold and using hoffman 40s will allow all radiators to heat at the same time, keep the pressure low (no greater than 2 psi) and you will have a well balance system
Let us know what are your mains pipe sizes and lengths and we could tell you how many Gorton 2 you will need on each main

http://www.nyrpcorp.com/hoffman-air-valves-air-vent-no-40

BobC

Make sure the pipes coming from the T on your second main both have slope so condensing water can find it's way back to that main UNLESS they are dripped at the end of each pipe. You don't want water to collect in any steam carring pipes.

Bob