Decreasing run time.

brandonf

Couldn't find anything in the search. And I know someone has spoken about it before.

Will better main venting decrease my boilers' runtime?
When it fires up my radiators whistle a bit, partly because the boiler is grossly oversized by at least 80-100K, and there are no main vents. My gas bill is high but I'm thinking that if the steam can get to my radiators quicker then they can heat- up quicker and lower my fuel consumption. Every little bit helps until I can afford to replace the boiler and near boiler piping.
Currently from a cold-start I get steam at the last radiator in the line in about 20-25 minutes and the first radiator in the line in about 12-16 minutes. 1100 SQ feet. Second floor of a two level building.
Thoughts? Opinions? All are welcome.
Thanks in advance.

Jamie Hall

That's slow. Adequate main venting will certainly help, but how much I'd be most unwilling to say. How long and what size are the (is the?) main, and what do you have for main venting now?

nicholas bonham-carter

Main vents will shorten the time for the air to escape from the pipes, and begin to rise up to the radiators. This is probably the most beneficial addition to your system you can make.—NBC

KC_Jones

Every house is different, but I can get steam to the end of my mains (longest is ~25') in about 3 minutes with the main venting I have.
For a house the size you describe I think those times are outrageous.

Keep in mind insulation can play a role in that. I have 1.5" insulation on all my pipes.

Neild5

How are you timing it? From when the burner starts or when the header is 200 + degrees?

KC_Jones

When the system is warmish (run within the past 30 minutes or so), that time is from a call for heat to steam at end of main. I have PLC control system on mine with an end of main sensor and it actually times how long it takes.

Fred

Main vents will help a lot. As is, all the air in the system has to be blown out of those small radiator vents. It will cut your run time. Having said that, what is your Pressuretrol set at? It should be set at .5PSI cut-In and the white wheel inside should be set to "1" so that the cut-out pressure is around 1.5PSI. Also, when is the last time you took the Pressuretrol off of the pigtail (looped pipe) and cleaned that pigtail? If it is plugged, the Pressuretrol can't see the system pressure and will let the boiler run at pressures well above what is desirable, which can also lead to hissing radiator vents.

brandonf

> @Neild5 said:
> How are you timing it? From when the burner starts or when the header is 200 + degrees?

From when the burner starts.
And it has no header sadly. Piped totally wrong. The near boiler piping is 1-1/2 copper 😢 piped like it was hot water. SMH

brandonf

> @Fred said:
> Main vents will help a lot. As is, all the air in the system has to be blown out of those small radiator vents. It will cut your run time. Having said that, what is your Pressuretrol set at? It should be set at .5PSI cut-In and the white wheel inside should be set to "1" so that the cut-out pressure is around 1.5PSI. Also, when is the last time you took the Pressuretrol off of the pigtail (looped pipe) and cleaned that pigtail? If it is plugged, the Pressuretrol can't see the system pressure and will let the boiler run at pressures well above what is desirable, which can also lead to hissing radiator vents.

Today was the first day I fired it up for the season. Upon first fire all the radiator valves started leaking and hissing. Which I found odd because I fixed all the leaks last year. So I went downstairs and realized that the boiler was running at 9 PSI but my settings were correct at .5 and 1. So I cleaned the pigtail which was clogged, and ran the boiler to make sure the pressuretrol was cutting in and cutting out at the right pressures. The pigtail clogs often because it is completely piped wrong which I have to remedy eventually.

brandonf

> @KC_Jones said:
> Every house is different, but I can get steam to the end of my mains (longest is ~25') in about 3 minutes with the main venting I have.
> For a house the size you describe I think those times are outrageous.
>
> Keep in mind insulation can play a role in that. I have 1.5" insulation on all my pipes.

I have circa 1910 asbestos insulation on all the mains and takeoffs. It's in good condition. No insulation on the incorrect copper near-boiler piping.

brandonf

> @Jamie Hall said:
> That's slow. Adequate main venting will certainly help, but how much I'd be most unwilling to say. How long and what size are the (is the?) main, and what do you have for main venting now?

The mains are: about 2-3/8" O.D.
Leaving boiler 16'length-elbow-12'length-elbow-16'length-elbow- 8'length-back at boiler.

I have 6 take-offs: they are all 1-3/4" O.D.
5 of them are 6.5 ft horizontal
1 of them is 16 ft horizontal and is last on the line.
All of them have 12 ft verticals up to the radiators.

Theres only one vent on the main which is a Vent-Rite no.33 on the first elbow about 16' from the boiler, after the first 2 take-offs

Jamie Hall

That vent is woefully inadequate for the job! Try to find a handy spot near where that 16 footer takes off where you can figure out how to attach a nice BigMouth. Could even be on the 16 foot runout, for that matter. Can you post a picture of that area of piping?

brandonf

@Jamie Hall

That 16' take-off comes off the main about 3 feet from the boiler. And the entire section is tightly encased in asbestos. I'm not opposed to safely removing the insulation from one of the elbows and Drilling and tapping for a vent...
Or I suppose I could drill and tap the end of the main just before it meets up with the incorrect copper near-boiler piping.

Jamie Hall

Sorry. Misunderstood. You want the new vent to be as far from the boiler on the main line (after all the takeoffs/runouts) as possible.

You may have to do some drilling and tapping...

I might add that with that boiler piping, it's a wonder it works at all -- but you already know that.

brandonf

> @Jamie Hall said:
> Sorry. Misunderstood. You want the new vent to be as far from the boiler on the main line (after all the takeoffs/runouts) as possible.
>
> You may have to do some drilling and tapping...
>
> I might add that with that boiler piping, it's a wonder it works at all -- but you already know that.

Well it's basically in a pitched rectangular Loop around the basement with two take offs on the left side, two take offs on the right side, to take offs on the back side, and none on the front side. The front sight is the furthest from the boiler but it's basically in the middle of the line. Maybe I should do one in the middle of the line and one at the very end?

Forgive my crude drawing and bad handwriting, and my dry marker...🤣

Fred

It's pitched with the highest side leaving the boiler, right? If so, you want to put your vent on the lowest side after the last radiator run out and before it drops down to the bottom of the boiler.

brandonf

> @Fred said:
> It's pitched with the highest side leaving the boiler, right? If so, you want to put your vent on the lowest side after the last radiator run out and before it drops down to the bottom of the boiler.

Yes it is. That sounds good. I can probably drill and tap it if it's not too big of a fitting. Not sure what the rules are for that pipe size and a big mouth. Does anyone know what calculation I have to use to size my vent?

Fred

brandonf said:

> @Fred said:

> It's pitched with the highest side leaving the boiler, right? If so, you want to put your vent on the lowest side after the last radiator run out and before it drops down to the bottom of the boiler.



Yes it is. That sounds good. I can probably drill and tap it if it's not too big of a fitting. Not sure what the rules are for that pipe size and a big mouth. Does anyone know what calculation I have to use to size my vent?

The Big Mouth is a 3/4" fitting but can be ordered with a 1/2" stem (if you call Barnes and Jones directly). In any case, if you can tap a 3/8" hole that will vent about the capacity of a Big Mouth. A 1/2" tapping is better but the diameter of your Main or an elbow may not be big enough to drill and tap a 1/2" hole. You can then put whatever fittings you need to increase the pipe to accept the 1/2" or 3/4" Vent.
Is there, by any chance, a Tee with a plug in it anywhere on that end of the main that you could use for the vent, without having to drill and tap a hole?

nicholas bonham-carter

Try one Big Mouth, and that should be enough to make a substantial difference.—NBC

EBEBRATT-Ed

@brandonf, if your pig tail plugs that often consider adding a second pressure control as a back-up. Use brass fittings and pigtails. a tee below the pressure control with a petcock on the branch will allow for blowing out the pigtail without removing the control

KC_Jones

On a side note, I hope you have the names of everyone that has worked in that basement, and you are sure to never call them, ever. Can't stand seeing crappy work, that a hard working person paid for.

brandonf

@Fred No there is not. 😢

brandonf

> @KC_Jones said:
> On a side note, I hope you have the names of everyone that has worked in that basement, and you are sure to never call them, ever. Can't stand seeing crappy work, that a hard working person paid for.

Luckily (I guess). All the bad work was done before we purchased the house. The sad thing is whenever the pressuretrol or gauge would clog from their improper piping I would call my plumber who actually does excellent work to figure it out and end up cleaning it. I'm very disappointed in him that he didn't actually repipe it correctly so it wouldn't happen again. (Which I learned how to do from this forum) But now I realize that he is a very good plumber but not a steam guy.

On a side note a very shrewd handyman owned the building before we bought it. I will lay odds that he installed that terrible boiler. we also had to report him to the gas company because when we took ownership we learned that the meter had been shut off for years but he had bypassed it to steal gas.
Luckily the boiler area and the venting are the only real sins here, which are easy enough to fix, but not very cheap. 🤣🤣

brandonf

@Fred
I Finally got the big mouth delivered. I'm going to tap a 3/8 hole. Is it ok to drill & tap into the pipe itself? Or do I have to drill & tap at a fitting like an elbow or tee?

Fred

Did you order the standard Big Mouth that is 3/4" or the 1/2" version? The 3/8" tapping may require you to use a 3/8" nipple and put a 3/8" to1/2" or 3/8" 3/4" coupling on it to accept the Big Mouth. I would be reluctant to try and tap a 3/4" hole into a 2' or 2.5" pipe. Even a 1/2" I'd probably tap into a fitting. Or, you may want to consider a Service clamp like this:

https://www.jcmindustries.com/media/54801/JCM March 2016 402 404 Service Saddles.pdf

Be sure to order the optional EPDM gasket which is rated for steam temperatures, the normal rubber gasket will not last.

See this thread for a picture of the Romac Service clamp with Big Mouth vent installed:

https://forum.heatinghelp.com/discussion/comment/1531505#Comment_1531505

brandonf

I ordered it off Amazon. It came in 3/4 but I picked up all the fittings to go from 3/8 to 3/4. So I will definitely be tapping a 3/8 hole. I just don't know if it can be done in a pipe or has to be done into a fitting.

nicholas bonham-carter

I would tap into the pipe, just as it goes down vertical at the end of the dry return. Cut just enough threads to hold the first brass nipple securely.
Come out 6 inches or so, then an elbow, and up as high as you can get. This arrangement will prevent any water hammer damage.—NBC

brandonf

Well here's how I installed it. Wasn't much room after the last riser. Don't beat me up too bad over it. It's not leaking. And the big mouth is working. It's not ideal but if it doesn't give me any trouble I'll leave it for a while till I can get more fittings.

I timed how long it took for steam to go from the Supply pipe coming out of the boiler to the big mouth.
It took about three minutes flat.
The big mouth shut about a minute after that.
I also uploaded pictures of what system I'm stuck with.
Using Dan's EDR book, my total radiation is 187 NOT including piping.

Main piping is approx 2-3/8" O.D. 52 feet.
Take offs are approx 1-3/4" O.D. 120 feet.
I can't seem to find the calculation for the piping EDR.

Fred

The BIg Mouth probably needs to be vertical. Watch it for a while but it may hold water pitched the way it is. If it does, it may spit or not even close when steam hits it.

brandonf

> @Fred said:
> The BIg Mouth probably needs to be vertical. Watch it for a while but it may hold water pitched the way it is. If it does, it may spit or not even close when steam hits it.

I watched it on two startups so far and it closed. So fingers crossed. 🤞

Fred

brandonf said:

> @Fred said:

> The BIg Mouth probably needs to be vertical. Watch it for a while but it may hold water pitched the way it is. If it does, it may spit or not even close when steam hits it.



I watched it on two startups so far and it closed. So fingers crossed. 🤞

It's going to take a few cycles to build up enough condensate in it to start to act up (if it does).

ethicalpaul

Wow 187 vs 500+? But that’s just the EDR on your floor, right? As in, there’s probably that much again on the first floor?

brandonf

> @ethicalpaul said:
> Wow 187 vs 500+? But that’s just the EDR on your floor, right? As in, there’s probably that much again on the first floor?

Nope that's the EDR for the whole system. The boiler used to service the first and second floor. But the first floor was converted to scorched air.

ethicalpaul

Wow, instant super-sized boiler. Seems like an odd thing to do!

brandonf

> @ethicalpaul said:
> Wow, instant super-sized boiler. Seems like an odd thing to do!

Seems pretty common. Nobody wanted to spring for a new properly sized boiler. Lol but they wonder why the gas bill is through the roof.

ethicalpaul

I meant converting the unit to forced air—that must have cost as much as a boiler

brandonf

> @ethicalpaul said:
> I meant converting the unit to forced air—that must have cost as much as a boiler

Oh. Well the first floor is commercial office space, so when they remodeled, they wanted HVAC and on separate utilities.