Where can I install main vents?

rhodie_

Hello. I'm back again for a couple questions. I had an oil boiler replaced with a gas boiler a few months ago. Plumber installed a hartford loop but used only one tapping and connected with 2" pipe straight up up the pre-existing bullshead tee that feeds the 2" main. The tee that goes to left is higher. It forms a loop all the way around the basement and reconnects to the tee lower. There are returns coming down from both the left side and the right, forming a hartford loop (i think). The one on the left is only for one radiator, as all the other water rolls around the main and eventually ends up in the return on the right of the tee. There are 8 radiators. 5 on the left (which i guess would be parallel flow as the steam and condensate are both rolling downhill. Then the main crosses the basement and feeds 3 more radiators before reconnecting. Those are sort of counterflow as the steam leaves the tee from both sides, so these three get fed from the right. There are no main vents, yet I have never had a pressure issue (do have uneven heating). The cycle is always satisfied by the thermostat. Recently, I insulated just about everything, and we also had a ton of insulation put in the attic. As a result, it's hot as balls upstairs, and cold downstairs. I've ordered 7 hoffman 1As, thinking I'd put them on and turn them down upstairs, plus one varivalve thinking it would that on the furthest radiator from the boiler downstairs, effectively venting most of the main quickly, and making it hotter downstairs, which would satisfy the thermostat downstairs faster and thus make it cooler upstairs. (heard they spit but the floor is vinyl.



I could also just put main vents in, but I don't know were to put them. There is no END to the main. It's a loop. If I put it in the middle of the basement, furthest from the boiler, whichever side the steam approaches from first, wins, closing the vent, overheating that half of the house, and leaving the other side and main, somewhat empty and slower to fill. (this can be accomplished with one varivalve on the 5th radiator on the left, anyway.



I have read about people venting the main on the dry return (that's part of the hartford loop, right?) but the dry returns are so close to the boiler, even though they're slightly below the mains, won't they just fill and turn off if I put the vents there? Path of least resistance?



Should I break the tee and cap the low end and make a fully parallel system that goes left and has a main vent at the end?



Should I break the tee and cap the high end and make a fully counterflow system that goes right and has a main vent at the end?



I've tried to find a pro in RI, but I just can't find one. A couple folks have helped with suggestions, and I'm going to follow up with them, but they're still not steam pros. I feel like I have to tell them what to do, so your help would be greatly appreciated. Also, if you are reading this and are a steam pro, please move to Providence. It's a friggin' gold mine out here. Nobody else seems to know what they're doing. :)



Many thanks. And a special thanks the the fellas the emailed me with local recommendations of people who at least have some working knowledge of steam. Those will be my go-to guys, I hope.

Mark N

Loop

Let me get this straight, right now you are feeding steam into both ends of the loop that run around your basement. Draw a diagram and post it.

Hap_Hazzard

Looks like

your basic "main-as-header" concept? Very creative.

Mark N

Main Loop

I reread your post. The near boiler piping is screwed up. Show your installer the diagram on how to pipe the boiler that is in installation manual. If you don't have it, it is online. Feeding steam into both ends of the same loop will cause steam distribution issues. Do you have water hammer?

rhodie_

Yep.

Header is basically the main.



Here's a rough diagram. Sorry about it being 2d. After the t, it goes higher up on the left and the main slopes all the way around and reconnects on the right at a lower level. The steam feeds in both directions, slightly faster to the left, probably because there are 5 rad

Vents helping. The dotted lines are my rough sketch of the return pipes. The return on the left only catches the water from the first rad on the left. The rest (7) drain into the return on the right.

rhodie_

A little knockin i think

Thanks Mark. I did talk to the installer but he won't repipe. This is how it was before and he said it has to be that way. Then I called us boiler and they actually ran it by their techs and said it is fine as is, and they will honor the warranty. They actually looked on here and said it was fine. It's a total dead end. I don't know if I have water hammer. I get some clankin but it's not super loud. Most of it is wood popping from expansion as they didn't leave much space around and against woodwork. It's definitely not silent. I did have them come back to skim. They didn't leave a skim port but cut out some pipe to skim and then replaced it. They put surge master in a month ago and it turned red and I was getting so much surge they there was no water visible in the glass while firing. They drained the whole thing, and it was filthy. Then refilled, fired, "skimmed" they say, and put another can of surge master in there. It's been green since. Can says it's ok to leave it in. I'm not sure what it is. Anyhow, seems to be fairly good since, but not quiet. They did put "squick" in there at the beginning, but that has since been drained.

Mark N

How it should look

This is how it should look.

rhodie_

Awesome!

So simple, that drawing. I really appreciate it. I guess that means you think I should go parallel flow with it instead of going the other way and making it counterflow. Is that because it's better for steam to roll downhill?



Also, I should mention that if I utilize both 2" tappings into the header, my main is only 2" anyway, so will using both tappings really matter? If it was 2 going into 3, seems like definitely you'd use both, but if it's all 2", maybe it's a moot point?



Your awesome diagram was one of the suggestions I gave my plumber, but he said it would take too long to get all the steam around and the first rad would be blazing hot and the last one cold, but that's not true, right? That's the point of the main vent...couple minutes to vent it all?



Thank you for everything!

Mark N

Options

It is always better to use both risers off the boiler to the header. It will result in drier steam. Multiple main vents at the end of the main will result in faster venting . Gorton #2's are the biggest vent around. The amount of vents you need is determined by how much air you need to vent. I posted another diagram splitting into 2 mains, 1 parallel flow the other counter flow. Usually a counter flow main is 1 pipe size larger and has twice the pitch of parallel flow.

rhodie_

Many thanks!

Looks like parallel is the way to go for me as the piping is pretty well built into walls now. Now if I could just find a steam pro in Providence...



Thanks you so much for your help, and the diagrams. This is really great info and advice.

Mark N

Main vents

Your welcome. As long as your heat is working and keeping you warm take you time and find a pro that will pipe it properly and do it in the spring. If one can't be found some home owners have done this themselves.

nicholas bonham-carter

Did he follow the instructions?

It's hard to see from the pictures. What sort of contract did you sign with the installer?

The manufacturer's instructions must be followed. This is a system with a lifespan of 40 years if correctly installed, but only 5 years when badly installed, as a result of water-hammer, and venting imbalance. Will the installer help you out with the diagnosis, and repiping to the correct arrangement?--NBC

rhodie_

I tried

Hi nbc. US boiler says its fine the way it's piped. I have no argument as far as the plumber is concerned. My contract was to install a new boiler. That's all it said. No details in the contract. Had I come here first I would have probably done things differently. There are no pros in providence tho, so I had to do something before the cold season started. At least it works, and and really is pretty quiet.

SWEI

US boiler says its fine

meaning they don't understand how it's actually piped.