Main vent needed and kind

jeffatncx · January 13

I have a small 2 story house w Dunkirk boiler situated in center of basement. 1 pipe system. At the end of 1 2.5 inch main, approx 20 feet, it T off to 1 3/4 pipe. About 4 feet from one half of the T are 2 vents stacked/ganged on one vent opening, a Gorton #1 and a MaidOMist 18. Time from furnace to vent opening is 1 minute w vents removed. With vents installed time is 1 min, 47 sec. The Gorton sits on top of the T and heats up first. The MaidOMist is on a 2 inch nipple (off to the side of the T) and take a while longer to heat up.

Does the MaidOMist vent take longer because it is a slower vent or is it because it is not right on the top of the T fitting?

Should I add another vent to the gang/stack/manifold (not sure what term to use) to try to get the time down to 1 minute,as it is w no vents screwed in?

Rad on this end of house are slow to heat.

ethicalpaul · January 14

I have to admit I don’t know what a Maid o Mist 18 is but regardless, 1:47 is pretty fast, there’s not much to gain there

jeffatncx · January 14

I added Maid O Mist pic. I dont have others of the setup can but get em

Steamhead · January 14

It's a #1, meant to compete with the Gorton #1.

109A_5 · January 14

Seems like you could do better. The way I see it, the less time you are burning fuel (each cycle) to push air out of the system, the more fuel you will save.

ethicalpaul · January 14

Well you can only vent air as fast as the steam can heat the main so the vent usually isn't even the bottleneck. He's getting 1 minute with an open pipe and 1:47 with his current venting.

Steamhead Member Posts: 18,267January 13
It's a #1, meant to compete with the Gorton #1.

Or the Gorton #1 was meant to compete with the Maid O Mist #1. I've never seen proof of which company set up their designs and numbering first.

Steamhead · January 14

I know Gorton had their #2 in the early 20th century. It was designed as the only vent in a Vapor system. The inside is the same as the smaller vents, only bigger.

jeffatncx · January 15

Thanks everyone. Think I will add another Maid O Mist, try to get that time down closer to 1 minutes. From the chart above, looks like it vents a little more and it's cheaper. Can anyone suggest why I should go with the Gorton instead?

109A_5 · January 16

Since the orifice is removable, I kind of wonder if the with old Maid O Mist and maybe the new one (although it probably would void the warranty), if the orifice could be drilled out a bit more. To get a bit more air flow through it.

Steamhead · January 16

ISTR the D orifice is the same size as the valve seat, so no, that wouldn't help.

109A_5 · January 16

https://forum.heatinghelp.com/discussion/comment/1882495#Comment_1882495

OK, thanks.

ethicalpaul · January 16

Warranty hahaha on a vent. I'm not really laughing at you, but rather at the unpredictable lifetime of any given steam vent

109A_5 · January 16

@ethicalpaul I thought you had at least one replaced under warranty, maybe I'm thinking of someone else. However thinking about it, who ever it was, I think the place they purchased it from did not want it back.

Anyway it does not matter apparently the D orifice is the same as the valve diameter so modifying it is useless.

jeffatncx · January 21

I added another Maid O Mist. Time to heat at the vents went from 1:47 to 1:28.
Not terribly significant I suppose but a change non the less. Just wanted to provide the update.

Steamhead · January 21

Did it even out the heating of the radiators?

jeffatncx · January 23

No, it didnt really help any. I have one in particular on the end of that line, 2nd Fl that "works sometimes, sometime no". I am trying to correct things that appear wrong or could be improved upon.

Steamhead · January 23

Try a Gorton #2.

ethicalpaul · January 23

https://forum.heatinghelp.com/discussion/comment/1883648#Comment_1883648

spending $150 to try to get the steam to the main vent faster than the 1:28 he currently has seems like a lot to spend for no possible noticeable gain

109A_5 · January 23

You could try a valve (inexpensive) and play with the main venting manually. Maybe a pipe plug with a hole drilled in it if you want to play with different orifice sizes.

jeffatncx · January 24

https://forum.heatinghelp.com/discussion/comment/1883652#Comment_1883652

Yeah, and as I understand it, with 3 #1 vents I am 3/4 of the way there already. Seems there is something else going on.

EBEBRATT-Ed · January 24

I agree with @ethicalpaul I don't think increasing the vent size will do anything. Your already pretty fast. And you could easily be off 20 seconds or more from the start time as you can't tell exaclly when the water starts boiling.

109A_5 · January 24

My main venting timing starts the instant I have to pull my finger off the boiler's supply riser, I think it is fairly consistent.

ethicalpaul · January 24

if the riser is cool enough to hold, then you aren’t measuring the speed of venting, you are measuring the speed of the main getting heated by the steam.

But either way it’s fine—sitting in a living room you can’t tell the difference as long as some decent venting is happening

109A_5 · January 24

https://forum.heatinghelp.com/discussion/comment/1883766#Comment_1883766

You are correct.

I guess I should add that is from a cooler start but while watching the cooler start and the steam coming up I also can hear the boiling and see the water in the sight glass start to move and the -1 - 0 - 1 water column pressure gauge just start to move. This all seems consistent with a hot start and my mains are insulated and don't cool down too fast.

The end of my main has two valves, one to open air, and one that shuts off the main vent for testing and/or for maintenance. So I can go from an open 3/4" pipe vent to no main venting at all.

Obviously a cold main takes longer.

ethicalpaul · January 24

those valves are great for testing, cool

dabrakeman · 1:37PM

With only 20ft of 2.5" main and a few feet of smaller you have more than enough main venting. The warmer the pipes the more the main venting will come into play as less of the steam being produced is condensed warming the mains. Thus the steam has the potential to advance more quickly and push out air more quickly. By the way, this is one reason why people tend to hear more hissing from their vents in the extreme cold because mains and takeoffs are all warmer when there is less time between boiler cycles.

Main vent needed and kind

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