Question about air vents on radiators....

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Old 12-15-08, 06:27 PM
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Question about air vents on radiators....

I was having some issuses with my heating. I have steam heat. Friend of mine came over and took a look. He told me one of the problems was my air vents on the radiators were all the same size in the house. He told me I should have air vents with a larger opening upstairs and a smaller opening on the lower floors. Not knowing anything about heating (I just purchased my first home) I came here looking for advice. Does what he told me sound right? and if so what number air vents should I be using?

Thanks
 
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Old 12-15-08, 06:52 PM
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Originally Posted by Lockman102 View Post
I was having some issuses with my heating. I have steam heat. Friend of mine came over and took a look. He told me one of the problems was my air vents on the radiators were all the same size in the house. He told me I should have air vents with a larger opening upstairs and a smaller opening on the lower floors. Not knowing anything about heating (I just purchased my first home) I came here looking for advice. Does what he told me sound right? and if so what number air vents should I be using?

Thanks
Was it originally designed like that or was it modified?

If it was like that originally, then it is most likely not.

make sure everything is bleed.

cheers
 
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Old 12-15-08, 07:02 PM
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Im not sure if it was modified. Also I thought I read on here becayse of steam heat I didnt need to bleed?
 
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Old 12-15-08, 08:16 PM
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Originally Posted by Lockman102 View Post
Im not sure if it was modified. Also I thought I read on here becayse of steam heat I didnt need to bleed?
don't know about that. My needs to be bleed and water comes out. might want to write down the boiler brand and google it for help
 
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Old 12-16-08, 06:56 AM
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You won't have to bleed a steam system.

You should have different vents on the radiators so that you can balance the steam distribution throughout the system. Generally, you want arger vents (faster venting) on the distant radiators and larger vents on the very large radiators (regardless of location. You want the all radiators to heat up at the same time, except you want the radiator in the room with the thermostat to be a (little) bit slower so you don't satisfy the thermostat before the other rooms are warm.

Before I got educated on the subject, I had balanced my system by restricting the flow to radiators with small orifice vents - now that I know better, I have rebalanced using the fastest (largest) vents I can get away with and it's saving me about 10% on fuel consumption. The lesson here is that the longer it takes the air to leave the radiator, the longer it takes for steam to fill it and the longer you burner will use fuel. There is a limit to how fast you can vent, especially on the larger radiators. Beyond a certain rate, too much steam will condense at a rate faster than can drain out of the radiator and it'll spit out the valve.
 
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Old 12-16-08, 08:57 AM
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Right, there's nothing to bleed in a steam system ...

A few other points...

The MAIN line from the boiler needs to be adequately vented. You want that main to fill with steam first so that the steam reaches all the risers at around the same time. If there are no, or too small, vents on the main, steam takes it's sweet-a55 time getting to the end, and the risers off the end of the main may not get enough steam before the thermostat is satisfied.

There are adjustable vents available for the rads which you can 'fine tune' to suit your needs.

The main supply and return from the boiler should be well insulated.
 

Last edited by NJT; 12-17-08 at 05:56 PM.
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Old 12-16-08, 07:49 PM
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Please elaborate on you heating problems.
 
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Old 12-16-08, 08:09 PM
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Excellent lesson Steve

To add to that unlike hot water radiator valves the inlet radiator valves on steam radiators are meant to be full on or off, with steam controlled at the vents unless it is a two pipe or 2-pipe with vac system.
 
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Old 12-16-08, 09:37 PM
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See this link for more info on venting steam boilers
Steam FAQ
 
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Old 12-17-08, 06:50 AM
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Ok......Im new to all this as I used to rent an apartment so bare with me if I sound ingnorant on some things. Main problem Im having is when I have the heat on my daughters room will not heat up enough....boiler and everything in front of house in basement......her room is on 2nd floor rear....If I have the heat on 74 it will be very warm on the first floor and warm in my bedroom (2nd floor front) however her room never seems to heat up.

We just purchased the house in August so this is the first time we are dealing with the heat and controls. Should I start by replacing the vents on all the radiators?
 
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Old 12-17-08, 07:50 AM
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If you currently have vents on the radiators and it is appropriate for your system, you should be looking at adjustable vents.

The ones lower and closer to boiler will be on minimum settings while 2nd floor back rooms at the highest. Over time you should be able to balance out house fairly well.

Providing supply piping is appropriate, it is important to have main vents most times on piping to get steam out to the extremities as fast as possible.

Most often occurring problem is people tend to crank up the operating pressure thinking it will get the steam out further and higher when in fact it usually does the opposite. Check your pressure and operate as low as possible.
 
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Old 12-17-08, 09:27 AM
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First, you should ensure that Main venting adequate as mentioned in a couple of posts. Once that's taken care of, then you need to speed up the delivery of steam to that room, or slow down the delivery of steam to the room with the thermostat. In my house, I have a Maid-o Mist #5 vent (.070" orifice) on the radiator in the LR (thermostat is near) and and "D" vents (.185" orifice) in the upstairs rooms . This arrangement may not be right for you, but you get the idea.

JacobusŪ Steam Vents - Maid-O'-MistŪ - Illinois

You can buy Maid-o-Mists at HD, but I've never seen anything larger than the #6 vents on the shelf. I converted #5 & 6 vents to "D" by drilling out the orifice to 3/16". Also, if you need new main vents, the ones I've seen at the home centers are woefully undersized. Get to a plumbing/heating supply house (or internet vendor) and get Gorton #1 main vents

BTW, It took me a couple of weeks of trying different venting rates (drilled the orifices incrementally larger) before I got the system balanced the way I like it.

One more thought. Are the pipes in the basement insulated? If not, this can slow down the delivery of steam to the far ends of the system, cause water hammer (banging) and other problems.
 
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Old 12-17-08, 05:54 PM
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Should I start by replacing the vents on all the radiators?
No... I don't see any point in that.

So, what is it, just one room that isn't getting heat? I would focus on THAT radiator first... check to make sure that the vent on that one is actually working... you could try replacing that one first with an adjustable...

Use a rifle, not a shotgun.

LockMeister, got a digi camera? Can you take pics and post them on a free account on Image hosting, free photo sharing & video sharing at Photobucket and provide a link here to view the album?
 
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Old 12-17-08, 06:10 PM
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Yes it really is just one room we are having trouble with. I can post pics here...what do you need pics of? Radiator its self? Boiler? Both?


Originally Posted by NJ Trooper View Post
No... I don't see any point in that.

So, what is it, just one room that isn't getting heat? I would focus on THAT radiator first... check to make sure that the vent on that one is actually working... you could try replacing that one first with an adjustable...

Use a rifle, not a shotgun.

LockMeister, got a digi camera? Can you take pics and post them on a free account on Image hosting, free photo sharing & video sharing at Photobucket and provide a link here to view the album?
 
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Old 12-17-08, 08:37 PM
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Take pics of everything ... it won't hurt for us to see the entire system.

Hey steam heads... (you know I'm steam stupid, right?) ... couldn't Lock just temporarily remove the vent on the cold rad? Just to see if he even gets steam out there?
 
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Old 12-18-08, 12:27 PM
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Yes, that's a good idea and great way to troubleshoot. Monitor the inlet valve to see how long it takes for it to get hot. You'll have enough time to re-install the vent before the steam gets to the far end of the radiator.



Originally Posted by NJ Trooper View Post
... couldn't Lock just temporarily remove the vent on the cold rad? Just to see if he even gets steam out there?
 
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Old 12-19-08, 08:47 AM
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ok here is a link to some of the pics.....The radiator IS getting some heat......just seems not to heat up like the other rooms. Im thinking from what I learned here already is the vents being all the same size and having a smaller hole to vent. Maybe her room needs a larger opening. Im guessing maybe an adjustable one like those suggested.

dhlexpress102/Heating - Photobucket - Video and Image Hosting
 
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Old 12-19-08, 02:52 PM
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Is the water in your boiler REALLY that dirty? If yes, then you need to blow down more often.
 
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Old 12-19-08, 02:58 PM
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the water runs dirty for about 2 seconds and than is clear. I think what you see is the glass tube itself..if you look above that you will see the water is clear.
 
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Old 12-19-08, 03:35 PM
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Unless you also "blow down" the gauge glass the water in it is always clear because it is mostly condensate, not boiler water. You don't have a valve for blowing the glass.
 
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Old 12-19-08, 04:11 PM
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Ok not to sound as dumb as I am lol What exactly is "blow down".....friend of mine told me to open the value just under the glass tube and let it run until the water coming out becomes clear....which normally only takes a few seconds..Should I let more water out? Also how high should the water level be on the glass tube?
 
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Old 12-19-08, 05:11 PM
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Blow down is a technical term with many meanings in the world of steam engineering. I'll explain two definitions that are important to you.

Residential steam boilers lose a bit of water every time they cycle. This loss of water has to be "made up" by periodically adding new water. Sometimes this is done manually and sometimes an automatic "feeder" is installed to do this when necessary. The downside to an automatic feeder is that the person taking care of the boiler never gets a feel as to how much water the boiler makes up over a period of time and consequently never knows if the rate of make up water is increasing.

All water contains both suspended and dissolved solids. The suspended solids can be referred to as dirt and these will settle out of solution when the boiler is not being fired. This dirt will build up in the lower parts of the boiler.

Dissolved solids are what cause "hard" water and are usually minerals such as calcium (most common) and others including magnesium, iron, chlorides and such. These will not settle out.

When water is heated and turned to steam only the water (and some air) leaves the boiler. The solids remain and with additional water and time the solids (both dissolved and suspended) increase. The dissolved solids eventually reach a point of saturation (the water cannot hold any more in solution) and then they will precipitate out of solution and adhere to the heating surfaces of the boiler. This is called scale and it makes a dandy insulator causing the metal of the boiler exposed to the fire to operate at a higher temperature and reducing the amount of heat transferred to the water. In time this will destroy the boiler.

To combat this it is necessary to periodically "blow down" the boiler. This removes the existing water that has a high concentration of solids and replaces it with new water that has a lower concentration of solids. Depending on the quality of the make up water and the amount of water lost during normal operation it may be necessary to blow down the boiler as often as once a week or as seldom as once a month.

To blow down the boiler you first want it to have been idle for a period of time. This allows the suspended solids to settle a bit and facilitate their being removed. If you have an automatic water feeder then close the manual valve on its supply pipe. Ideally the drain on the boiler will be piped to a floor drain but in case it isn't you need a short hose from the boiler to the floor drain or to a bucket. Drain out about a gallon or so of water or from the normal operating level in the gauge glass to just above the bottom of the gauge glass. If the water is extremely dirty then increase the frequency of blow down but not the quantity blown down at any one time. If the water is clean then decrease the frequency. After blowing down use the manual feed valve to raise the water level back to the normal cold level in the gauge glass. If you have an automatic feeder then open the valve previously closed.

(More on next post.)
 
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Old 12-19-08, 05:36 PM
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The previous post described the need for and procedure for boiler blow down. Now I'll explain about "blowing down the gauge glass".

The glass tube on the side of the boiler is called the gauge glass. It shows the approximate level of the water in the boiler although it is only accurate when the boiler is at room temperature. At higher boiler temperatures the gauge glass level will be slightly lower because the water in the glass will be slightly less than in the boiler. (This will be on the test. )

A proper gauge glass will have three valves, a steam valve (upper), a water valve (lower) and a drain valve (bottom of gauge glass fitting). The steam and water valves must always be open unless you are changing the glass and the drain valve will be closed under normal operation. Sadly, most residential boilers either have no drain valve or a poor drain valve that it is almost impossible to operate without getting burnt. This is sad because it means the person in charge of the boiler never properly "blows down" the gauge glass and therefore never knows if the glass is properly showing the water level in the boiler.

When operating, the water in the gauge glass will almost always be crystal clear. This is because the steam in the boiler enters the top of the glass and condenses because the glass is cooler than the boiler interior. This condensate rolls down the glass and displaces the denser water (denser than what is in the boiler because of the temperature difference) causing the water in the bottom of the glass to return to the boiler through the water valve. To get both the true level in the boiler AND see the color of the boiler water it is necessary to blow down the gauge glass. The quick method is to open the drain valve and allow the steam and water to escape for a few seconds. A better way, one that also checks the free communication of the steam and water passages to the boiler, consists of opening the drain, closing the steam valve, (allows only water to come through the water valve and out the drain), closing the water valve (checks that both steam and water valves hold tight), opening the steam valve (allowing only steam to exit the drain), and then opening the water valve and closing the drain valve.

The above procedure should be done once a month during the heating season. This will ensure that the gauge glass and its passages are clear.
 
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Old 12-19-08, 06:32 PM
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That right there is a lesson... excellent... steam stupid ole me lernt sumpin. Thanks furd!

Just to clarify one thing ... when you refer to the 'drain', you mean the bottom drain on the boiler, correct? I'm thinkin' yes, becuz that's where the settled out solids are gonna get sucked out from...
 
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Old 12-19-08, 06:38 PM
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Lock, none of the pics seem to show the mains in the basement, and ya never answered whether or not the pipes are insulated.
 
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Old 12-20-08, 08:57 AM
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the pipes in the basement ARE insulated......as far as the main...Im not sure what you mean....I will try to take more pics of the whole room and see if you can see what you need to.

Thanks for all your help
Bill
 
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Old 12-20-08, 09:29 AM
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Maybe her room needs a larger opening. Im guessing maybe an adjustable one like those suggested.
Could well be the case...

Is that a block of wood under the vent in that radiator pic? That's not supporting the rad, is it? Looks like you might have a pain getting that vent off... yer sure it's not just clogged up with paint, yes? (steam stupid me talking, I don't know that it's even possible to clog up a steam vent with paint... just a thought)
 
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Old 12-20-08, 12:42 PM
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Originally Posted by NJ Trooper View Post
That right there is a lesson... excellent... steam stupid ole me lernt sumpin. Thanks furd!

Just to clarify one thing ... when you refer to the 'drain', you mean the bottom drain on the boiler, correct? I'm thinkin' yes, becuz that's where the settled out solids are gonna get sucked out from...
I used the word "drain" a bit to freely. When blowing down the boiler you use the drain on the boiler. (On a "real" boiler and not the toys they put in houses this is called a bottom blow valve.)

When blowing down the gauge glass you use the drain on the lower gauge glass connection. Sometimes there is no drain, just a pipe plug and most often on residential boilers there is a valve similar to the radiator drain on your car. I, of course, ()would remove the plug or lousy drain and install a real valve and pipe it to the floor drain but most people would use an old soup can and a pair of pliers to open the lousy drain.
 
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Old 12-20-08, 12:45 PM
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Originally Posted by NJ Trooper View Post
Could well be the case...

Is that a block of wood under the vent in that radiator pic? That's not supporting the rad, is it? Looks like you might have a pain getting that vent off... yer sure it's not just clogged up with paint, yes? (steam stupid me talking, I don't know that it's even possible to clog up a steam vent with paint... just a thought)
What I think you see as a block of wood (under the vent?) is some kind of plastic box with a window in it. Maybe a CO alarm?

As for being able to clog a steam vent with excess slopped on paint...yes, that most assuredly is possible.
 
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