Counter Flow in "new house"

jbmoff

Hi Everyone,
Just recently moved to a house built in 1929. Original steam COUNTER flow system.
I have followed Dan's site since late 1990's; my previous home built in 1903 had a parallel flow system that I had working perfectly thanks to this site, its newly installed main vents at the end of the dry returns, new pipe insulation, a lowered pressuretrol, and rads that were finally pitched the correct way.
Now, onto this new set of problems:

The new boiler (Slant Fin) installed in 2008 never had its main vents replaced, so immediately after moving in on 3/31, I went down to inspect the boiler and found that the main vents are NOT at the end of the mains. Rather, as the piping leaves the boiler and goes into the main, just after about one foot, there is a 10 in pipe that drops into what appears to be a dry "return" runs about 3 inches and then...a main vent! So, as you can imagine, steam enter the main, runs the 12 inches and then drops and rushes toward the two, Dole #1's. It does the same thing on the main that runs toward the other half of the house. I took off the old vents, and put on two Dole #1's on the longer main and one Dole #1 on the shorter. You can hear the air rushing out of the Doles and then as soon as the steam hits the float (after about 15 seconds) - CLICK- closed - and the main is then vented through EACH RADIATOR VENT - quite obvious when you are standing in each of the rooms.

Question is...WHY are my main vents installed there and not at the end of the main 15 or so inches back, up on a nipple....?
I am more than sure they are in the wrong place.
Thanks,
Jeff

Charlie from wmass

installer did not know what they were doing

Fred

They need to be moved to the end of the Mains and you need to make sure you put enough venting on those Mains to effectively vent the air out. The rule of thumb is the equalivant of 1 Gorton #2 vent (venting capacity of 1.1 CFM @ 1 ounce of pressure) for every 20 ft. of 2 inch main. Those Dole's don't come close to enough capacity.

JUGHNE

Are there any plugs at the end of the original mains where there may have been air vents?

jbmoff

Funny part is the piping where the vents are is ORIGINAL to the house and where the new piping from the boiler joins. If you saw the old vents, you would know what I meant...and those vents had holes the size of pinheads.
End of main on each side does not seem to be where the vents were. In fact, I am nearly 100% sure there were no vents there. Was told the house was coal before the gas conversion, though.
The ends of my mains USED to have a runout to two rads. The rads have since been removed and the runouts cut. They plugged the take off from the main. Can I remove the 45 elbow, put in a 15 inch pipe, raise the vent 10 inches and then close off the main?

BobC

You solution will work fine, just be aware the Gorton #2 is a large vent (7" high?) so make sure you have the room.

Bob

jbmoff

I forget that bugger is that large! The vent should have at least a 15 in length of pipe AFTER it, correct?

Fred

jbmoff said:

I forget that bugger is that large! The vent should have at least a 15 in length of pipe AFTER it, correct?

Doesn't have to have 15", especially since it is a counterflow. All the condensate will be running away from the vent so it shouldn't collect any crud. Just needs to be after the last radiator run out.

JUGHNE

Abandoned take off have helped me out a lot for venting. You are lucky they are at the very ends. I believe that having some 90's & nipples before the vents would make up for the fact that you might not have room for the often quoted 15" pipe length.
Also this is a counterflow, yes? So there should be no if any condensate near your vents. Only steam/air borne debris should get there?
Could you show us your near boiler piping?

jumper

Maybe your house originally had vacuum vents on radiators?

Counterflow gets no respect. But there were multi-storey buildings successfully heated with counterflow. Risers went above highest radiator and that's where main vents went.

jbmoff

Well, not sure if the rads had vacuum vents. There are typical vents on them now. I will post a photo of current main vent locations
and near boiler piping tomorrow. Thanks for all the feedback so far.

jbmoff

Here are some pics of boiler and piping. I tried to get three. One to show the boiler, and two others looking at the left and right mains.

Charlie from wmass

You described it well. If you look at the Weil McLain PEG installation manual it shows how to pipe a counterflow header. Pick the one for the boiler closest to your E.D.R. rating. Separate the supply pipes to their own take off tees, and put the vents at the ends of the mains.

jbmoff

Question: the boiler is a Slant Fin. Should I still look at Weil Mc?
Also, are you suggesting that EACH main should have its own supply from the header and not the one, single supply on mine supplying both?

Fred

Yes, each main, counterflow or parallel flow should always tie into the header seperately.

jbmoff

I found this diagram. However, it only shows a tie in to ONE main. Would anyone have a schematic for TWO mains AND is there a minimum length the header should be. I can see its height above the boiler, but nothing regarding how long it should be.

Charlie from wmass

that will work. You simply use a tee off the large horizontal main in the diagram.

jbmoff

So where the right, 90 degree elbow is, replace with a tee to both mains? How long should the header be?

Charlie from wmass

here is a photo of one I did.

jbmoff

Wow! Looks great. At least I know how mine should look. Plus, mine was also
Installed with a Hartford Loop!