One Rad cold

Kbalz

too much?

How much pitch is too much? Also, what sort of problems can that cause?

Kbalz

new

You may want to start a separate thread (here http://www.heatinghelp.com/forum-category/93/Strictly-Steam) for your problem so that the hints/tips we are getting from the members here don't get confused with each other

Rod

Radiator Slope & Vents

Hi- Problems with too much radiator "tilt"-  Take a look at the diagram, if you put a lot of slope on the radiator, the condensate then "pools" at the inlet pipe and interferes with steam trying to get into the radiator.  When steam first enters the radiator and is hitting the cold metal insides, the condensing is quite high and a lot of condensate (water) is produced. When steam condenses it goes from the size of a cubic foot down to the size of a cubic inch. This results in a large vacuum void which new steam rushes in to fill. If the incoming steam collides with the outgoing (or pooled) water you can get noisy water hammer and in some cases the water since it can't escape, builds up at a certain point blocks the steam entering the radiator. You just want enough slope towards the inlet so that the water knows which direction to go.

 Venting - While large amounts of venting are no problem for the steam mains, you can "over vent" radiators.The old steam gurus had a saying, "Vent you mains quickly and the radiators slowly"   If you "over vent" the air escapes too quickly with allows a lot of steam into the radiator at one time and when the radiators are cold this can mean (see above) a lot condensate is produced which even with a properly sloped radiator can cause problems. With radiators the thing is to find a nice balance between speed and quiet operation. This is where adjustable Hoffman radiator vents (1 A) or adjustable Vent-Rite vents are a big benefit.

- Rod

jamesm1

maybe

Thanks, I did put a level on that; it has slope but is less than the pipe on either side of the problem area. ALSO the main changes from 21/2 to 2 at this point. So I took the vent off , no change, left it off and ran ithe boiler for an extra long period of time today and the rad did eventually heat up . So could this point be an accumulation of sludge/rust/whatever causing a problem? PART2 : A rad on the other side of the building stopped working today, going from the boiler the main splits up, so this is (maybe ) unrelated. Even with the extended run time the rad remained cold. This rad worked fine previously, although it was always last to heat up and is last on the line. I am thinking this is an unrelated problem which happened at the same time but I would never bet on that. Same experiments tried- take off vent, open top of turn off. No steam, NO AIR comes out but the main and the return line(same) stay hot. If this is a test I fail.

jamesm1

Thanks again ROD

After more reading it seems highly likely the first problem is a slope problem as well as sludge buildup. I will try to clean that out tmro. The second problem still does not make sense though. I will inspect it closely and if I'm lucky it will be the same . I will, of course let you know.

BobC

venting requirements

Your 70ft main is a 3-1/2" pipe and it has about 4.7Cf so you probably need 2 or 3 Gorton #2 air valves to vent that main quickly.



Are all the radiators 6 tubes deep as that one photo shows? In your table i assume you mean W is the number of sections and D is the number of tubes per section. You listed the size of the pipe that feeds each radiator but I need the approximate length of each pipe frm the radiator back to the steam main. Don't go crazy, 20% accuracy on the length will do fine.



I'll have to look around to see if I can find what the EDR of those radiators are and then a conversion factor to see how much volume they hold.



One thing to consider is the venting ratio between radiators is equal to the size of the radiator and the relative piping for that radiator. If radiator A is twice the size of radiator B then A will need twice as much venting ASSUMING the piping to each is the same.



Glad to hear it's the LWCO leaking, that's a LOT cheaper than a new boiler!



Bob

BobC

Venting calculations

Those radiators are thin tube type (1930's) and i based everything on the number of tubes per section and the number of tubes along with the height of the radiator.



These are the results for your main and the radiators. I know what vents you need for the radiators but i don't know the length of pipes feeding each one so can't really say what vent should be used where. What i can say is that The family room will need roughly six times the venting of the 2nd floor bath, any drastic differences in piping would have to be taken into account.



Your Vent A is an unknown quantity, Vent B is a Hoffman 1A and is adjustable over the range of 0.026cfm to 0.226cfm. So in a perfect world the large family room radiator would be set to 5 or 6 while the second floor bath would be set to 1 or maybe 2. all of this is somewhat guess work because it depends on the differing need for warmth in any area because of comfort requirements.



I guessed you would want to vent the radiators at 1/5 the rate of the mains, but that is only a guess.





Main Steam Pipe: 70' and 4 inches





- 3.5 ID and about 4.7 cu ft to vent. Use at least 2 Gorton #2's (maybe

3)



Radiators - I've attached two types of Radiator Air

vents that are in my home. A (cheap Chinese) and B (good quality). I

also wasn't sure how to describe the width and such of the radiator

parts, see my labeled picture as a reference.



I measured the

feed pipe's using circumference / pi = OD



First Floor



Dining

Room

OD: ~1.7" 1.5” ID is 6.75 cu in per foot (10 ft is 67.5 cu in or 0.039 cu ft)

H: 34"

W: 8

5 4.33/section * 8 = 34.1 EDR and 0.44CuFt

Vent: A



FamilyRoom1

OD:

~1.7"

H: 24"

W: 24

5 3.0/section * 24 = 72 EDR and 0.96 cu ft

Vent: B



FamilyRoom2

OD:

~1.7"

H: 34"

W: 5

5 4.33/section * 5 = 21.6 EDR and 0.28 cu ft

Vent: B



2nd

Floor



Bath:

OD: ~1.43" 1.25” ID is 4.69 cu in per foot (20 ft [second floor] is 46.9 cu in or 0.054 cu ft)

H: 27"

W: 6



3 2.0/section * 6 = 12 EDR and 0.16 cu ft

Vent: A



MasterBR:

OD: ~1.7"

H: 34"

W:

7

6 5.0/section * 7 = 35 EDR and 0.46 cu ft

Vent: A



BR1 (Son's Room)

OD: ~1.7"

H:

34"

W: 7

5 4.33/section * 7 = 30.3 EDR and 0.39 cu ft

Vent: A



BR2 (Guest Room)

OD:

~1.7"

H: 34"

W: 6

5 4.33/section * 6 = 26.0 and 0.34 cu ft

Vent: A

jamesml

Didnt work

I checked that pipe where it was low slope and downsized by cutting a hole on the top. Clean with no buildup. This is still a bit of a problem with the rad taking too long but the other new problem is worse now. The rads have been cold for 2 days. Hot main, hot condensate return, hot riser at the bottom , COLD at the top. Took off top of turn off again. Nothing comes out. Put a wire down, no blockage. This makes no sense. My local expert says steam trap letting steam thru. I took top off steam trap which is at the end of the line . Water is running thru it , even backing up a little bit . The 1/4 inch drain hole does not allow any steam thru as it is always filled with running condensate. This problem makes no sense.

Kbalz

amazing

This is an amazing amount of information, for that I can't thank you enough.



As for the feed pipes, I'm not sure how to guess how much feed pipe is berried in the walls. They appear to Tee off and angle up although I can't tell at which angle, or which Tees go to which rads.



I just put in an order at PexSupply. Budget constraining me to a total of two main vents, I can add the third sometime next year if needed.



It will be a week before I get and install everything, I'll post back an update then.

Kbalz

3.5 ID?

I noticed you wrote the Main is a 3.5 ID, but above we determined it was 2" ID. Does this affect your calc?

BobC

Main size

If that 70ft steam main is 4" in diameter OD then the ID would be 3.5". And that 4" would be the pipe not including any insulation on it.



Exactly where did we determine it was 2", are you sure your not referring to the boiler takeoff's and header?



Bob

Kbalz

above

Search this text on this page, this is where we determined the OD/ID



How should I measure the Main Steam Pipe



Correct, did not include insulation.



Perhaps I measured the pipe in the wrong place? I got that measurement from the pipe right above the boiler (vertical piece).



Tell me where on the main pipe I should measure and I'll redo that today.

Steamhead

Did you measure

the outside diameter or the circumference of the steam main? 

Kbalz

D

I measured the diameter, and it was a pretty poor measurement as I recall.



I'll redo it tonight, using the Circumference using my sewing tape. It certainly doesn't appear to be 4 inches in person however.

BobC

measure main's size

You have vertical pipes coming off the boiler that go to a boiler header. A pipe comes off that and feeds into your 70 ft main. Go down that main til your a couple of feet away from where the main is connected. You can give us the circumference or the pipes diameter.



As to the length of the piping that feeds each radiator we just need a general idea of what length of pipe feeds each radiator. Just assume any pipe going to the second floor will be within a few feet of the radiator on the second floor. Say you have 12 ft in the basement and the trip to the second floor is 10 feet and then throw in 2 ft for the trip over to the radiator - that gives up a total of 24 ft. As i said we need this just to see if there are some radiators with very long runs.



Bob

Kbalz

header

I'll measure the basement portion tonight. I'm having a hard time wrapping my head around which stems from the main pipe, feed which 2nd floor radiators.. there is one stem that is not near any second floor radiator (or a first floor radiator)



I counted the vertical pipe that leads to the boiler header as part of the 70 ft measurement. The words you used "feeds into the 70ft main" seem to imply it is actually separate ? Or I may be interpreting it wrong. Also the boiler header, is that just the term for the elbow directly above the boiler?

Kbalz

2.5

The Main Steam Pipe 2.5" OD. I measured in several places using Circumference to calc the diameter. All of the near-boiler piping is this size, as well as the main that runs around the basement.



As for the feed lengths, there isn't much additional in the basement.. only three Tees around 2 feet each.



Lets say the first floor rads have 3' each, and the second floor has 18' each

Kbalz

update

Hello, haven't heard from anyone in a few days, wondering if this new 2.5 OD main steam measurement, and feed pipe estimates will change any of the previous numbers provided by Mr BobC.



I ordered 2 Gorton No. 2's, and 7 new Hoffman 1A - I figured I'll just replace them all now. They will arrive this week.

BobC

late reply

i think my mistake was thinking your stated 70 foot 4" was referring to a 70ft long 4" diameter pipe not a 70'4" pipe.



If the OD is 2.5" then it is a 2"ID pipe and that has 2.65 cu ft volume. The two Gorton #2's will do a fine job of venting that main and boiler header. those have 1/2" mounting so you will need reducers to put them on 3/4" pipe nipples.



As to the radiators I would vent them according to the edr of each radiator with a little added for those on the top floor. So A large radiator on the top floor might be set to 4 while the same radiator on the i'st floor would be set a bit lower. A small bathroom radiator might be set to 1 unless it it on a cold corner of the house and then it might be set for 2.



Ideally you would want all the radiators to heat at about the same rate so you have to play around with the individual vent settings to get them balanced. By venting the mains fast and the individual radiators relatively slowly you can get everything balanced. It is an art that takes some fiddling.



Bob

Kbalz

Excellent

BobC, thanks for returning, and clarifying.



For the Gortons.. I've seen two designs for their piping. One design is two vents on each side of a single Tee.. resembling a football fieldgoal upright. The other design is one elbow off of the reducer / union pipe.. then two Tees neighboring each other.



Which is the preferred design for my vent piping, which will start right at the end of the main (not 15" back)? Is there a minimum amount of height I must have above the pipe for the vents? Also, the pipes that will feed the vents, do these need to be pitched back toward the main?



I'm starting a new thread for my leaking LWCO, since its kind of a separate issue we discovered along the way.

BobC

Antler

Your probably best to come off the existing tapping and elbow over 15" or so (make sure you do it so water can flow back to the main) and then a Tee to mount vent #1 - a nipple and an elbow to mount the other vent. You want to get the vents up at least 6-8" from the main. As i said the Gorton #2 is large so you want to make sure you leave clearance for them.



Bob

Kbalz

On Hold

I installed all new radiator vents. The main steam vents have arrived, but I won't be installing them quite yet. Lots of asbestos that I would be potentially stirring up, there is one small tear in the insulation near the main vent tap.



We are likely going to get the asbestos completely removed this month.