Main Vent questions

pnm2

I'm wanting to install new main vents to get a fresh start on trying to balance my system for the first time, now that I'm learning about this stuff. I found these two near the boiler.

Strangely, the silver one is just a regular "C" size air vent that you'd put directly into a radiator (sorry, didn't snap a photo before putting it back). The other one, as you can see in the picture, says it's size No. D (although the diameter of the thread is larger than my radiator vent inputs).

I was under the impression, from what I've read so far, that main vents should be size #1, and that C's and D's were for larger radiators, no? Is there a good reason someone (I don't know who -- maybe a pro, maybe my dad decades ago, maybe previous owners...) might have installed these? I also noticed there are bushings (I think that's the term?) to reduce the original size of the inputs for the vents...wondering why someone might have done that, too.

Should I use these vents as my guide and replace them with the same exact sizes, or should I consider this an error and get two #1s? Or something else?

Thanks in advance!

Fred

Those vents a way too small for main vents. Back when boilers were coal fired, venting was less critical because the furnace "simmered all day long. Today with gas or oil, they fire intermittently and it is important to vent the mains as quickly as possible. You can't over vent mains but, at a minimum your vents should be sized based on the amount of air that needs to be evacuated. A rule of thumb is one Gorton #2 (or the equvilent) for every 20 ft. of 2" pipe. It looks like you have the head room for Gorton #2's. They will vent at twice the rate that a Gorton #1 vents. I use Barnes and Jones Bigmouths, available at Supplyhouse.com but some have had problems with them leaking. I have not. The Bigmouth vents at over twice the rate of a Gorton #2 and costs the same.
The reason for the reducers is to accommodate the size of the old vents they used. The "D" vent comes in different diameter sizes even though the vent rate is the same. Pitch those old vents and size the new ones to what you need to effectively remove the air as quickly as possible.

pnm2

Thank you!

Jamie Hall

That one vent tipped to lie horizontal (a Gorton?) isn't going to work that way. The can must be vertical.

pnm2

Wow, thank you.

ethicalpaul

D is the same as a #1 is my understanding. A #1 can do a lot of venting

pnm2

The guy at the plumbing supply place talked me out of a Gorton #2 -- said I don't have the space because they're huge and that they don't use them for houses. Does that sound right? Just want to make sure I'm doing the best I can since the improvement after installing the Gorton #1's this morning hasn't been as profound as I was hoping. (Still tweaking the radiator vents, though...)

KC_Jones

You appear to have the room and he’s wrong, used all the time in houses, sometimes multiple on one main when the main is long enough.

ethicalpaul

pnm2 said:

...the improvement after installing the Gorton #1's this morning hasn't been as profound as I was hoping. (Still tweaking the radiator vents, though...)

Supply house guy is wrong, but the number 2 are huge and expensive, that part is right.

what method are you using to determine if your main venting is sufficient?

pnm2

Man, that’s annoying, because I was so determined to go all the way, and I’m sure they won’t accept returns now that they’re used.

Do you guys know if there’s a market out there for barely used Gorton #1 vents, or will people not touch them?

I’m not using any scientific method to determine the size. I’m just under the impression that you can’t over-vent mains, and so I want to err on the side of excess to make sure nothing is holding my system back.

Beyond that, one of you mentioned that a rule of thumb was one Gorton #2 for every 20 feet of 2 inch pipe, and it’s hard for me to imagine I don’t cover that much since I’m in a large 3-family house.

Lastly, I’m still hearing some whistling (certainly at least “breathing”) from my radiator vents. I’m still tinkering with them, but I would imagine the most likely culprit is the mains still not venting fast enough. Is my thinking off track here?

KC_Jones

pnm2 said:

I’m still tinkering with them, but I would imagine the most likely culprit is the mains still not venting fast enough. Is my thinking off track here?

You are not off track there.

Also, no reason you can't add the #2 and #1 vent on the main together.

There are a couple methods to determine main venting.

1. Measure the length and pipe size of the mains and post it here, we can help give a recommendation. The 20' of 2" pipe is a good rule of thumb, but you still need to know the length. After you get those number post them here and we can make a recommendation.
2. Pull your current vents, leave the pipe open, run the system and time how long it takes from the header being hot, to the time the end of main is hot. Then install vents until you get close to that time. This will be your actual maximum. That said if you get within 10-15 seconds you are probably good, as it would be a big expense to shave off the last little bit and probably won't pay you back. Of note, if you have 1/4" pipe opening on the one main you will want to pull the bushing as that is a tiny opening and would surely be a restriction.

pnm2

When you say "length" of the mains, do you mean the visible length on the basement level before they go up to the other floors?

Also, in some cases I may have to guess at it, since some areas are not visible.

I'm pretty sure the bushings are fused on. In any case, I'm too nervous to test that theory with a ton of pressure, in case I break the pipes.

Lastly, in the interest of economy, is there an option of just keeping the two Gorton #1's I installed and simply adding more by splitting from the same opening?

KC_Jones

Yes, the length of the basement piping from the header to the end after the last radiator take off. If you have overhead returns there is typically a point where the pipe size reduces and returns to the boiler that is the point to measure to. If you have wet returns (low to the floor or buried in the floor) you measure to the point where it turns down, pipe size typically reduces here also.

Fittings can be tough to get apart and if you aren't comfortable, it is usually best to wait until warmer weather.

A vent "tree" is perfectly acceptable and done frequently. I have one in my own house because I didn't have room for the #2 vent, just keep in mind it takes quantity (3) #1 vents to equal a #2, plus the cost of fittings.

ethicalpaul

I'm a huge fan of KC's second method where you pull the vent and time the steam. It removes all doubt and takes no math. The #1 is a great vent. My main is 50 feet, split between 2" and 1.5" and a single #1 vents it fine.

pnm2

Okay, so one main looks to be about 1-1/4 inches thick and I was able to measure about 18 feet length before it went into a wall. It was close to the end of the house, so I can't imagine it's more than another several feet beyond that. This main definitely has room for a Gorton #2 where my Gorton #1 is installed.

The other main looks to be about 1-1/2 inches thick, and unfortunately I could only measure about 3 feet length before it went into a wall. It still has a decent way to go before reaching the edge of the house (assuming they do that before going up), so I would imagine it's a similar length (maybe more, maybe less) but that's a complete guess. This main doesn't look like it would have room for the Gorton #2, as there is a big pipe just above where my Gorton #1 is installed (see picture).

So...please let me know what this tells you as far as my venting needs. Thanks so much!

KC_Jones

I would suggest you are working from the wrong end. That appears to be an overhead return pipe which will be smaller. Start at the boiler header and check that pipe size and measure from there.

KC_Jones

I'd say your best bet is the method of removing the vent and timing. Measurements would help get you in the ballpark, but if all your pipes are covered it's going to be tough.

pnm2

When you say "boiler header", do you mean it's those large, insulated pipes that come out of the top of the boiler that I should be measuring instead?

If I try your second method of removing the vents and timing the steam, could you please walk me through how to properly (and safely) do that? I'm imagining:

1.) Shut off the boiler. (Do I need to wait for it to completely cool first?)
2.) Remove the main vents.
3.) Turn the boiler back on as I start my stop watch.
4.) What am I looking for? Do I put my finger over the openings to feel for air? Or do I watch the holes for visual signs of steam? Something else?

Lastly, I'm guessing it's not unsafe to run the boiler while the vent holes are open then?

Thank you!

KC_Jones

Yes the header is above the boiler and may be insulated. If you post pictures of the boiler and piping I can mark up the picture to explain it all.

Your steps are correct. What you are feeling for is "steam hot", once you feel the boiler header, or main takeoff is steam hot, start timing. Then go to the end of the main and when that pipe is steam hot, stop timing. This will be the baseline you are trying to get close to. Once that's steam hot, turn the boiler off and replace the vents. Pipes get hot fast, so when I've done this I usually start feeling well before the end of main so I know it's on the way and can be prepared.

It is perfectly safe to leave the vent out for testing as long as you know where the shut off switch for the boiler is and can get there in a timely fashion. It isn't a big deal.

pnm2

It sounds like maybe you're talking about these large pipes with the white insulation (see photo)? If so, they seem to run in a lot of directions and are hidden behind the ceiling of the finished section of the basement once they leave this boiler room, so I'm guessing your second method is my best bet.

I just shut off the burner to get prepared. The pipes are still warm, and it sounds like you're telling me I should start from them being cold, so I'll give it awhile.

For clarification, you're saying what I'm timing for is when each end of the mains (where my vents currently are) gets steam hot to the touch, correct? I'm not looking for any visual or other cues. So removing the vents isn't a matter of giving me access to the opening for a cue but more just to let the steam run through the length of the system unimpeded. Am I understanding correctly?

And I begin the timer not when the boiler starts but when the header pipes coming out of them get steam hot (which I imagine won't take long after flicking it on). Right?

Thank you again for holding my hand on this.

ethicalpaul

No, don't start from completely cool.

Start from "just recently has steamed"

That's my opinion anyway. If you start from cool, then the steam will have to heat up so much pipe that the "time from header to main vent" will be very long. Any vent can keep up with that pace.

If you catch it after or during a call for heat, when you are sure steam has gotten to your radiators, then shut it down, wait 5 minutes, then:

- start the boiler and your timer
- go stand at the open vent port
- wait for steam (well, condensation clouds) to appear
- stop your timer

That will give you the baseline for how long it takes with basically unlimited venting. Then you start adding vents to see how the times compare.

pnm2

Okay, not sure if I did this right, but here's my report so far:

- The boiler had been off for nearly an hour since its last run. The return pipes still felt warm to the touch.

- When I saw ethicalpaul's message not to let it cool all the way, I went ahead and flicked on the burner and started the timer as soon as I heard the flame light up.

- About 7 minutes in, water started spurting out of one of the vent openings. Because of this, I shut off the burner before the other vent opening could be reached by steam (or water).

- Once the burner was shut off, water no longer spurted out and only steam came out of that opening. But again, the other opening had not been reached (yet?).

Does any of this tell you guys anything?

pnm2

UPDATE: I decided to try it once more about 20 minutes later, thinking maybe the water was a result of the pipes cooling off too much.

Once again, water spurted out, this time only 3 mins 15 secs after the flame came on. Due to the water, I once again shut off the burner before anything could reach the other vent opening. (I'm thinking maybe I can test the other vent opening without making a mess by first screwing the eliminator back on this one?)

In any case, I'll await your guys' feedback before I try anything else.

ethicalpaul

It sounds like your boiler is "carrying over" water into your main(s). That is too short a time for it to be condensation from your radiators.

I can't quite see what is going on with your near-boiler piping from the picture above...has anyone on this forum told you yet that your boiler is piped wrong?

You can try putting the one vent back on to see what happens with the other main, but be ready, it might spew water too.

KC_Jones

We can't definitely say the near boiler piping is causing the issue, but for me, it's the most likely candidate. You shouldn't have water spewing out like that even with the vent removed.

The way it's piped could certainly be carrying water over as it appears to be a colliding header. Meaning each boiler take off is sending steam/water at the other take off and the mains are in between. Here is a graphic from a Peerless manual showing what goes on.

ethicalpaul

And when you solve this carryover problem, you are going to have better performance, because all that water getting chucked into your main will "kill" a lot of steam

pnm2

I just put the vent back onto the water-spewing opening to test the other opening out. By then the burner had been off for maybe 1-1/2 hours.

Once again a little water started dribbling out of the air vent before anything happened with the other opening. Then, about 6 minutes after the boiler flame went on, the pipe around the other vent opening got "steam hot", though I couldn't visually see any steam. (This might have been stupid, but I did put my hand over the hole and could feel hot steam/air coming out as well.) Anyway, no water-spewing from that hole, so I do have that going for me at least.

I'm having trouble comparing that diagram to what I have going on. Do any of the photos below tell you if my piping is good or not? (I drew a yellow circle around the vent from which water spewed.)

We just had this boiler put in less than a month ago. Do I have to call this guy back and try to explain to him that he might have done something wrong? I hope not.

Fred

Well, It's not piped correctly. Take a look at the installation manual.

KC_Jones

The header is supposed to go in this order when both boiler outlets are used.
Boiler outlet/riser
Boiler outlet/riser
System takeoff(s)
Drop to equalizer

What you have is this:
Boiler outlet/riser
System takeoff(s)
Boiler outlet/riser
Drop to equalizer
The last 2 are sort of intermixed, but not correct no matter how it's viewed.

You say this is brand new, have you made final payment? If so, my fear is you are stuck with this unless you shell out more money to have it fixed, but we recently had someone on here that had a contractor fix their mistake after having a rep come in.

It isn't correct, and there isn't any arguing that point, the question is will the contractor fix it?! That we can't answer.

I will say this, to fix it will require him to undo all the piping up to the mains, build an actual header, then connect the mains into that. The existing piping they tied into may have been ok with the old boiler, but it's not proper spec for this boiler.

I can't tell for sure, but will ask, do you have another boiler, and a water heater exhaust venting all tied into the same vent as this boiler?

pnm2

I'm guessing this is the relevant page regarding my piping issue (please see photo)?



I apologize, but I'm having trouble making sense of this or seeing what the piping mistake is. Could you please point it out to me (perhaps it's one of the three "WRONG" examples in the manual)? I just want to be able to point it out to the guy who installed it, rather than try to explain that something is wrong but I don't know what.

Also, is the piping error you're seeing the likely cause of the spurting water?

Thank you guys so much! I'm hopeful that this discovery is the root of my system balancing problems.

KC_Jones

The closest "WRONG" in that manual to what you have is the second one "Take-Off Between Risers", but the equalizer is a bit off because of the offset connections from the boiler.

If, and honestly it's a big IF for me, the contractor is even able to realize what he messed up I doubt he fixes it for what was already paid (no pricing discussion here).

I feel you paid for a proper install, which this is not, and they should make it correct.

I marked up your picture to show what will need to be taken out and rebuilt to make this correct. This is what should have been done in the first place.


Here is a picture, very roughly showing what it should be.

pnm2

Sorry @KC_Jones , I didn't see your reply until after my last comment.

Unfortunately, we did make final payment, but we do have a prior relationship with this contractor so maybe that will help. I had no way of verifying his work before, as I've only begun my interest/education in our system after this recent installation. I just always crossed my fingers that he's doing what's right.

When you say a contractor fixed their mistake after a "rep" came in, who do you mean? A rep from the boiler manufacturer?

We do have another boiler, but it's not for steam heat. I don't believe they're connected in any way, but here is a wider shot to give you a bigger picture.

KC_Jones

Yes the contractor called the manufacturers rep to confirm if the work he did was right, which it wasn't. We haven't heard back on that one, but supposedly they are going to fix it properly. Thread is here.
https://forum.heatinghelp.com/discussion/181656/rookie-here-2-pipe-steam-system-with-no-traps/p1

I don't think the venting on the other boiler, tied in with the water heater is correct, but someone else with more knowledge may comment.

Another thing that just dawned on me, how did he size the new boiler? I'm guessing if this is a 3 story/family house it may be right, but given the other errors...well let's say incorrect sizing is a common mistake. To size they need to measure every rad in the house, do you know if that was done? Sorry for a can of worms on your original venting question, but when I notice things I tend to comment, hopefully for the benefit of the poster.

Also, for more education, if that small boiler is for some hot water heat in the house, if the load is small enough, it can actually be run from a heat exchanger off your steam boiler. Just some future thought if that boiler ever fails, that you might not actually need it.

pnm2

@KC_Jones Thank you so much for taking the time to mark up the picture for me.

When you say "no pricing discussion here," do you mean that's a policy of the forum? It seemed to me that we paid an extremely generous amount for labor alone when you break down the total hours he was here...so I hope he'll do what's right.

He did replace the previous copper piping with steel (or is it iron?) to bring it up to code, which we would not have been aware of, so that made me feel like he had our interest in mind to some degree.

KC_Jones

Correct pricing isn't allowed by forum rules. If you wanted to bounce it off someone pricing is allowed in private messages. I'm not a pro, but am very aware of what materials cost and what appropriate labor rates should be. I also agree with the forum rules, so many variables it's not really an appropriate open discussion and can just cause hard feelings, though it took me a little while to fully understand that.

pnm2

@KC_Jones He also installed that other boiler, I believe last year. It's not for hot water, it's for heating the finished part of the basement.

He definitely did not measure anything to determine the boiler size. We simply switched out the previous boiler with an identical make/model. (After reading Dan Holohan's book, I now realize this reasoning was bad, and that we should have had someone calculate what's needed rather than assume the original size was correct. I'm crossing my fingers that it just so happens to be correct, but of course I don't know.)

Believe me, now that I've gotten so deep into the weeds with this stuff and am aiming for perfection, if worms are in the can I want to know about them...so thank you.

KC_Jones

It's for hot water heating, so that does answer the question. He may not even be aware it could be run off the steam boiler, not a big deal.

KC_Jones

pnm2 said:

Believe me, now that I've gotten so deep into the weeds with this stuff and am aiming for perfection, if worms are in the can I want to know about them...so thank you.

Welcome to the club, it's addicting, in a good way, well that's what I tell my wife.