Help, please, with main venting, double radiator venting Q's

hotrodandflash

Hello, wise ones. I'm just learning here. Have been reading Dan's Lost Art book and Gerry and Steve's venting capacity manual. I suspect a big part of my problem with heating the front half of my detached three story building is because of inadequate venting. (One pipe steam system, newish gas boiler, back half of house heats up just fine, front half terribly, especially on cold days.) What I realize is that I have only one main vent, which seems inadequate. Attached is a pic. Looks like it is improperly placed, too. In the photo, the steam pipes are the ones with the main vent attached, obviously; the other piping you see in the foreground is not part of the steam system. That steam pipe on the far left is the main that runs directly across the cellar from the boiler to the part you see here (it's partially insulated; I'm working on that). There are no other main vents than the one you see on the right of the pic, right at the elbow leading to the return.



1. I know that main vent is improperly placed. Does it need to be moved? Or can I just add one or more Gorton #2s to the main, in a better place? If I understand correctly, they should be placed AFTER the the pipes go vertical but BEFORE the downturn for the return; but there is not really room for that, unless I put an angled nipple right in the center of that photo there (but it won't allow for the recommended spacing)… I'd like to add one or more main vents to the system; where you would you put them? Before all that you see in the pic, just down toward the end of the straight run?



2. Some of the radiators upstairs get only 1/2 to 2/3 hot at best, even when the radiator valves are BLAZING hot. All of those under performers on that side of the house have newish, clear Gorton Ds on them. Sound like a venting problem at the radiator? Or a problem with the radiators themselves? Can I just add a second vent to each of them, and if so, what size would you use?



3. There are two exposed (but now insulated) vertical mains in the front of the house (one on the first floor and one on the second), and there are no vents on them. If I install a vent to each of them, what size and type would you recommend?



4. In the pic, the insulated pipe on the top running to the right only feeds into one radiator the floor above; that radiator barely gets any heat. In fact, the pipe itself gets blazing hot right at the start there, but just five feet later, before it turns to go vertical, it is nearly cool to the touch. What can that mean?? I replaced the radiator air vent on the radiator that sits right above it on the floor above; it's a Gorton 6 and is new and clear. (It's the garage right above there, so honestly I'm not that concerned with making that radiator heat up more, but frankly I'd like to know what the problem is.)



Thanks so very much, in advance. I've paid an absurd amt of money to "heating pros" in my area, and none have even recommended additional venting! And none of their "fixes" have helped, at all, so I'm trying to figure this out myself now. Grateful for this board!

BobC

Vent and slope

Rather than drilling and tapping the main it would be easier to remove the existing vent and use an elbow with a 12-16" nipple and another elbow to mount the vent(s) on. Just make sure the horizontal nipple has a little slope so water can find it's way back to the boiler.



The amount of venting you need depends on the amount of air in each main, your Gorton #2 vent is rated at 1.1CFM  - if your main has 2 cubic feet of air in it you would need 2 of those to vent the main quickly.



Check all horizontal piping with a level (don't trust your eyes) to make sure it has the correct slope; if you suspect a dip in a main stretch some string along it and see what it looks like. Put a level on every radiator, some may need a little shimming to ensure water drains out. Any pooling water in a pipe or radiator will collapse steam, you want to hunt those pools down and eliminate them.



Bob

hotrodandflash

main vent locations

thanks, bob. I thought about adding a vent or two to the main on an antler where the current one is, but I was worried that it's not placed correctly…? Would it still be best to add it there, despite the location at the end of the line right where it angles directly to the return?



Also, would you go ahead and add vents to the vertical mains on floors one and two?



I've checked the pitch of all the radiators (fine, with some quarters!), but I'll double check the main…



Thanks very much.

BobC

venting

Do your main vents get hot at about the same time? If they do not then something is making it easier for the steam to travel down one main than the other.



If you can set the main vents up the way I explained it would be the same as having that vent in the preferred location, it's always best to get vents up as far as your head space allows also.



What kind of vents are on the other radiators in the system? It's usually best to vent radiators slowly and mains fast so they all get steam at about the same time. Starting out with slow vents on everything then increasing the vent rates on the problem radiators to see if that helps. You can  add vents on risers or on the supply side of a problem radiator to speed the delivery of steam but make sure all the piping and the radiators are sloped correctly first.



Bob

hotrodandflash

re: venting

Thanks, Bob. The vents on all of the back of the house radiators are Gorton 4-6 (sized based on proximity to the thermostat, which is in the center of the second floor, plus the fact that the back of house heats so well). The vents on the front (the problem side) are ALL Gorton Ds right now. They were smaller before, and going up in size definitely helped, but not enough make the front and back of house anywhere near even. (And short cycling doesn't seem to be a problem after I figured out that the thermostat was set at 5 CPH and I changed it to 1, and now to 2, since it seemed too get too cold in between firings.) I have a heat/plumber coming tomorrow, so I'm going to see if I can get him to vent the main more, as you suggest. Thanks. Would you go ahead and have him vent the risers (that means the vertical pipes that run btw floors, right?) too?



The radiators are pitched correctly, and they are located very near the risers (or the vertical main, if I'm not using the correct terminology!); I can't see the piping very near it, as it goes into the ground right next to the valve, so I can't be sure about that pitch without ripping up the floor or ceiling…