How important are air valves to the efficiency of the steam system?

tomsloancamp

I’m curious how important do you all consider air valves are for a steam system. I have been experimenting with a variety of air valves and have begun replacing inexpensive valves with Gorton valves, using their guide to choose the right valve.I am surprised by the effect the change in valves has had in my system. In your experience do cheap valves cause an otherwise  good system to underperform? 

EBEBRATT-Ed

Without good venting a steam system will never perform right.

However it isn't always the original installers fault. A lot of steam heated buildings were originally coal fired. Coal fired boiler fired continuously and if venting too a long time ....so what.

These same systems converted to oil or gas burners that cycle several times /hour did not work well with the original small vents

nicholas bonham-carter

I would say, “without good main venting, the system will not perform properly.”
The Gorton website, when last I looked, glosses over this important fact, and instead focuses on the distance from the boiler.
Vent your mains fast, and your rads more slowly.—NBC

Jamie Hall

I wouldn't have said "important". Good venting isn't just important, it's absolutely essential. As our hero and guru in chief has pointed out -- if the air can't get out, the steam can't get in He might have added -- i it gets out in the wrong place at the wrong time, things won't balance. If the steam gets out, you lose water and the system rusts out.

Essential.

tomsloancamp

my main air vent is on the opposite end of the main loop (square-shape) instead at the end. This has made it somewhat difficult to balance the distribution . There are two large downstairs radiator, two small upstairs radiators before the main vents and the kitchen with 2 upstairs radiator branch off after the main air vent. I have 2 Gortons on the main vent that replaced the original vent. Definitely noticed the radiators heat up quicker and the thermostat shuts off sooner, almost before the radiators are entirely heated. I guess I was surprised by how quickly it reached the desired temperature just by switching out 2 cheap radiator vents with Gorton’s.

EBEBRATT-Ed

@tomsloancamp

Can you post some pictures or a piping sketch? I have see steam mains fed from both ends tied together above the water line which will drive the vents crazy

tomsloancamp

@EBEBRATT-Ed here a some photos of the main loop with the pipes branching off ... I hope it makes sense. These photos are the first leg of the run from boiler. The large radiator in dining room is first.

tomsloancamp

Now we have second leg coming up to the opposite side from the boiler which branches of another large first floor rad and then two rads on 2nd floor.

tomsloancamp

This one is of the main vent. Someone had theorized that this may have been after the last original rad. The thought was that the kitchen had a large oven that heated this side of the house (American Four Square -1920’s.)

tomsloancamp

Here’s the rest of the main line with the kitchen, then a run that splits for 2 upstairs rads and then back to boiler

nicholas bonham-carter

A piping sketch would be easier to follow than these separate pictures.
Put arrows on the sketch showing the direction of flow of condensate.—NBC

tomsloancamp

JUGHNE

You need to have your steam main venting at the end of the return at the boiler. Until than you are spinning your wheels with radiator vent changes.

Is the return and steam main tied together up high at the boiler??
Your first picture is that a crossover pipe just above the roll of insulation sitting on the floor?
Another picture to clarify would be good.

Jamie Hall

May I go so far as to hope that those 2 medium radiators 2nd floor are ties into the steam main, and that after that -- but before the boiler -- the steam main turns down and goes into the boiler's wet return? The sketch isn't really clear on that point.

If that is the case, the main venting must be after where those two radiators take off, but before where the main turns down to the boiler.

On the other hand, something you said implies that you have two risers off the boiler -- a "second leg coming up to the opposite side from the boiler which branches of another large first floor rad and then two rads on 2nd floor." which would imply that you have two risers, feeding two separate steam mains... ???

Can you unconfuse me here?

tomsloancamp

Here’s a picture of the boiler with piping. Ther return is marked. There is a riser to the 2nd floor radiators and a short riser to the small kitchen radiator on the last leg before the 90 turn towards the boiler. Both rises are after the main vent. I believe these 2 risers were installed after the original installation. I couldn’t find any sign of a place where there would have been a vent close to the boiler.

EBEBRATT-Ed

Looking at the very first picture one main is sure like it's pitching up. Is this counter flow? That extra drip at the boiler indicates that as well.

I have seen jobs with two different steam mains tied together at the far end and the steam from one main closes the air vent first and the other main stays air bound.

Not clear on the piping layout

JUGHNE

No pictures with your 11:52 posting.

tomsloancamp

JUGHNE

That pipe with the 6" or so of white insulation looks to tie your steam main into the what you have labeled as return.
Your drawing indicates that the flow is CCW around the house.
The real issue is the piping set up to drain water CCW around the house.
The standard is parallel flow of steam and condensate water in the same direction. This would require the steam pipe at the top of the boiler being the highest point of the piping and therefore all water condensed at the steam travels would flow by gravity back to the return and drop down the uninsulated black pipe to the bottom of the boiler.

So can you tell if the slope of the pipe from the top steam pipe fitting (90) is then downhill consistently from the boiler around the house all the way back to the return?

If that is the case then the return pipe should not be tied into the steam main and your venting should be at the end of the return or just after the last rad takeoff connection.

Some systems can have parallel flow for part of the steam main and then have counterflow flow for other part of the system.
That is where the steam goes one way and the condensate is flowing back in the opposite direction (thus counterflow).
Most runouts to rads are counterflow piping.

Some of your piping looks sloped back towards the boiler.
Counter flow mains need a "drip" pipe to keep the water from coming back thru the main and running down into the top of the boiler.

tomsloancamp

@JUGHNE if I’m following you correctly, the flow of steam and condensation are the same. I have colored in the photo with red being the pipe leading out of the boiler and blue being the end of the main returning. There definitely is a consistent downward  slope of the main. 

Precaud

The pipe with white wrap that connects the main to the return looks wrong to me. It's shoving steam up both ends of the main.

My system was piped that way, correcting it made a huge difference.

I would close off that pipe and install main vents after the last radiator in the loop.

tomsloancamp

@Precaud I agree and not sure why that was ever there. The lighter patch of concrete is where the original American Standard boiler was located. I wonder if that would be a reason why they would connect. I wasn’t sure if the boiler was coal fired before oil either?

Precaud

tomsloancamp said:

@Precaud I agree and not sure why that was ever there. The lighter patch of concrete is where the original American Standard boiler was located. I wonder if that would be a reason why they would connect. I wasn’t sure if the boiler was coal fired before oil either?

That could be. And it could be that piping it this way was considered ok back then by those who didn't know better. I had two local "pros" service my system in the past, and either they didn't notice or weren't bothered by it.

EBEBRATT-Ed

@tomsloancamp

Where are you located? Did you check "find a contractor" on this site?

tomsloancamp

Here’s the original boiler and header.... sorry about the photos 

JUGHNE

To me it looks like your blue return is connected to the red steam main by the short crossover (white tape) pipe.
And was that way on the old boiler also.

You could remove that insulation on the cross over.
There might be a union under it.
Picture if you do, please.

This probably worked after a fashion for coal burning which gave you constant low pressure steam. It may have relied upon the small slow rad vents for air removal....did it once a season perhaps as the coal fire may not have died completely out.

But as you know now we fire up 2-3 times per hour and air must be removed quickly for best results. Air reenters thru the air vents after each firing and the cycle resumes.
This is a major change from coal design to on-off burners.
The thought was that it worked with the old coal burner....it should work with the new oil or gas.

We overlooked the difference for many decades and as a result slow heat delivery at higher cost. Giving steam a bad reputation.

tomsloancamp

@JUGHNE I think you’re right about the system setup for coal. There was a cut out of the basement floor below the boiler and I’m curious if another boiler existed before the red American standard that is pictured above. I’ll check out what’s below the insulation on that crossover pipe. Is it better for the return to not be insulated to encourage condensation? 

JUGHNE

Usually returns are not that hot, yours's is because to looks to be back fed from the main.
The steam main will be hot up to the main vents, which in your case would probably be at the boiler.
But to see what is under there it needs exposed.

Precaud

tomsloancamp said:

Is it better for the return to not be insulated to encourage condensation? 

It depends on where the main vent(s) are. If you remove that crossover and vent after the last radiator, the pipe after it won't be anywhere near as warm as it is now. That's where part of the efficiency gain comes from.

EBEBRATT-Ed

@tomsloancamp

I see your in RI. Try @New England SteamWorks

New England SteamWorks

Your picture is the correct way to pipe this. The red and the blue should not be connected above the waterline, as they are now. Remove the connection and install main venting there instead. The drip becomes the condensate return. Easy.

Not a big fan of those boilers for steam though....

tomsloancamp

The pipe appears not to be original. It was there before I had the boiler replaced because the paper wrapped insulation isn’t new. Maybe at some point in the past someone replaced this pipe.

tomsloancamp

Thank you everyone for helping me figure my system and the issues with the venting. I prefer not to mess with the piping and moving the main vent right now. I’ve replaced the larger radiator vents with the Gorton #4 to assist the main vents and it seems to work. It’s not the correct way to vent the system however it will do for this upcoming winter. We have put a bit of financial investment in our home over the last 2 year, including pulling from my retirement ☹️. The system works much better now then it did. I spend way less on fuel cost. I realize some individuals might not agree with the boiler choice but for my budget it worked.

Precaud

From your pic, it looks like that crossover pipe would be pretty easy to cut and remove, and then plug the ends... it wouldn't take a steam specialist, any plumber could do it.

tomsloancamp

Would that be an adequate placement for a main vent?

Precaud

Now you're thinkin' Absolutely.

JUGHNE

In theory, you could cut out about a 6" chunk of pipe in the middle leaving a couple inches out of each fitting.
Spray numerous time with PB Blaster or such.
Then unscrew each piece, plug the steam fitting and then a nipple with reducing 90 pointing up, another 90 side ways, a longish nipple horizontal to a tee then nipple to another 90 and mount 2 vents on the tops, the whole horizontal section has to slope back to drain any water.

Removing those short pieces is much easier said than done.
IIWM, I would do it during a warm spell.

If they will not unscrew.....good chance of it, then
you may have to cut the pieces off where there is about 1/2" sticking out. Then cut inside the nipple across the threads with a saw with out hitting the fitting threads. Make a few cuts and then chisel the pieces out.
A little time consuming for the first time but it does work.

tomsloancamp

I’m assuming the return pipe would need additional support once the connector pipe is removed. Generally, is one side of that pipe reverse threaded?

JUGHNE

Unlikely left/right threads, typically these are normal threads.
There is most likely a union close to this junction.

tomsloancamp

I found this from Dan himself describing a system similar to mine.... https://heatinghelp.com/systems-help-center/how-they-piped-coal-fired-steam-systems/ . I’m think it’s best to keep the original vent active and add another close to the boiler.  He suggests more vents are better for a converted coal to oil system 

motoguy128

I’ll add to the others. Get the mains vented fast and the radiator vents are just fine tuning, as steam will have a preferential flow to larger radiators with larger laterals even if they have the same vent size as a smaller one. Vent size become even less critical the tighter the boiler sizing is.

If you vent radiators too fast, steam rushes into to too quickly and I believe it starts mixing with the air or perhaps you get a see-saw action with a radiator vent venting and sucking intermittently. The result is you get less complete heating, which means less steam is consumed, and pressure rises.