main vent question

DM_2

I bought a house with a 1 pipe steam system last summer and had a new boiler installed. At the time I knew nothing of steam and didn't know to have the contractor put in main vents or wet return drain valves. Through this site I have learned alot and changed out all the broken air valves and lowered the pressure to .5 cut in and 1.5 cut out (from 2 and 4)and the system is working well(very quiet). My question is where to have the main vents installed, I have a 2" main that runs 55' through the rear of the house which feeds 7 rads then drops down to a 1" return and comes back to the boiler. The other 2" main splits off the first one at the riser and goes 25' through the front, feeds 5 rads then drops to a 1" and returns to the other side of the boiler. Can I put the vents on the 1" return back at the boiler room before it drops into the dry return or do they have to be at the end of the 2" mains?(there is not enough height at the ends of the 2" to put 6" nipples and a vent). The rads don't hiss but the far rads don't get very hot unless I take off vents (Gorton D's).
Also, are wet return drains essential?
Sorry for the long question, any help would be appreciated.
dt

gehring

main vents

First, I am another DIYer (not a pro), but I saw no one responded to your question, so I'll give you my layman's take on it. If I am picturing your system correctly, you say the mains "drop down to 1" and return to the boiler" (one coming from either end of the basement). I am assuming they are both returning well above the water line of the boiler (probably just below and at opposing pitch to the 2" mains going out) and then each have an elbow back near the boiler where they drop down further (perhaps vertically?)to the wet (below water line) return. If that is correct, then the main vents should be located on those 1" lines, back near the boiler (before they make the drop down to wet return), each on a tee approx. 18" back from and before their respective elbows and each should be set up on 6-8" or greater nipples. The pros can give you specific air volume calculations to recommend the exact size of vent(s) needed, but as a rough comparison, I have a what sounds like a fairly similar system design and I have one Gorton #1 on my long main and two Gorton #2's on my short main. Again, if your system is different than what I have described then disregard my commnets. Now you know enough to ask more specific quesions from someone who really knows what they are talking about. I am still a student of steam myself, so I qualify my response accordingly.

gehring

correction

Correction. I have two Gorton #1's on my short main and one Gorton #2 on my long main. (I reversed my Gorton references).

DM_2

main vents

Thanks gerhing, yes you are correct about the piping and there is room for nipples and vents back in the boiler room. Should I have wet return drain valves installed while he's at it? I wish I knew this stuff when I had the boiler replaced.

gehring

drains

On my system the two returns join together as one before they go into the Hartford Loop. Right before going into the Hartford loop (and where the wet return is at its lowest point) I insalled a drain valve. I also installed a gate valve in my Hartford Loop. That way I can close the gate valve, isolate the return condensate from the Hartford Loop and waste the condensate down the drain (for skimming the boiler or for flushing out the returns). Also, since the drain is at the lowest point of the return I can periodically drain a little water out of the return line to make sure it is not filling up with any sediment down there. The way I see it, if you use a proper good quality drain valve it gives you more options when working on your system -can't think of a reason not to since the expense is nominal, but again, I am not an expert so I am also interested to hear what the pros have to say.

Steamhead

Just got back from work, DT

now to answer your question.... I would use a Gorton #2 on your long main and a Gorton #1 on the short one. The best place for these vents is at the ends of the steam mains rather than the dry returns- you don't need to fill the dry returns with steam. If you can't find Gortons in your area, go to www.gorton-valves.com to ask who carries them. If no one does they will sell direct to you or your contractor.

If you can't install the vents coming out of the top of the main, the best thing is to drill into the side of the last steam takeoff tee on the main and tap it for 1/2" pipe thread. Then install a short nipple and a 90-degree ell pointing up and mount the vent on the ell. Make sure the horizontal nipple pitches back toward the main so it won't trap water. The #2 has its own little built-in riser while the #1 would need a short nipple. Though this is not a textbook procedure, I've had 100% success with it.

You might want to have a pro do the drilling/tapping/installation as it requires some care. Check the Find a Professional page of this site to locate one near you. If you're in the Baltimore area, e-mail me!

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