Webster Boiler Return Trap questions

SteamPupil

We have a customer with an old steam boiler system and a "newer" steam boiler that was installed before they purchased the house. I am having problems with getting steam to a radiator that is fed off the end of one of the farthest steam mains. That 1.5" steam main travels some 85' with 17 90° elbows. Additionally, it is currently predominantly uninsulated and poorly insulated in the small area that there is insulation. There are two 1/2" thermostatic traps (replaced in the last month) on that steam main. The first is located approximately 50' from the boiler and is required due to the fall of the pipe before it takes a small vertical rise. The second is located at the end of the steam main near to the radiator take-off.

The boiler generally cycles off before steam ever reaches the end of this steam main. As it approaches the end of this main you have some water hammer as a result of the condensate remaining in the end of the main. If I have a long enough run time and the water fully drains down the condensate return line, then I get steam at this radiator. However, I believe part of my problem is poor condensate return. This brings me to the Webster boiler return trap (model 0 23?) and the inverted trap that are currently installed by the boiler.

There is an inverted trap at the boiler. There is not a lot of fall in the condensate return line to begin with and I would estimate that this inverted trap reduces that fall by half. I can come up with no explanation for the inverted trap except that it appears to be equal to the center line of the Webster boiler return trap located nearby. I do believe that the Webster trap is now improperly installed. I question whether it is needed at all and if it is not needed then I would surmise that I can also eliminate the inverted trap. It appears that the Webster trap used to drain condensate that formed in the steam main off the boiler but when the current boiler was installed it, I assume, was repiped incorrectly.

Obviously my recommendation is to insulate the 1.5" steam main. Am I correct in also assuming that the Webster trap is not needed or not functional as installed and I can eliminate both it and the inverted trap? Do I need a vacuum breaker or air vent on the condensate return line.

EBEBRATT-Ed

Looks like the inverted trap is some attempt at a false water line to keep the return trap working. Need more pictures and info

SteamPupil

You put it more succinctly, but that's what I thought as well. What other information and or pictures would you like?

SteamPupil

In the upper left of the first picture there is a pipe supported by perforated strap. That pipe leads to the return trap. You will notice directly above it a vertical pipe with a cap that comes from a tee on one of the steam mains. I believe that the Trap used to be piped to that now capped vertical pipe. Instead the pipe that leads to the steam trap is coming off the horizontal end of the steam main.

Jamie Hall

Look up Webster vapour systems either in your copy of LAOSH or in the resources here on the web to get an idea of how it was supposed to be hooked up -- do that before you start playing with pipes and adding or subtracting things.

Webster was a vapour system. Check your system pressure (needs to be low) and check for any crossover traps which got removed etc. etc.

And -- most important -- insulate that misbehaving steam line. There is no way you are going to get steam to that radiator with that long an uninsulated line in any reasonable amount of time. That is probably 99% of the problem with that radiator.

Steamhead

The Webster system, like the Dunham system shown in chapter 15 of Lost Art, had a single air vent installed at the ends of the dry (overhead) returns where they come together near the boiler. I don't see that vent in your pics. That's probably the issue here, but how about posting a pic of this point so we can be sure?

SteamPupil

Jaime, I've just purchased LAOSH on Amazon. I will download the Kindle version in the meantime.

If I understand correctly, a crossover trap is simply the name for a trap at the end of a steam main? I had one steam main that had been connected directly to the wet return (it was obvious new work as it was copper piping) to which I already added a trap. I don't believe there are any other missing crossover traps but I will check the next time I am on-site.

I have previously spoken to the homeowner about the need for insulation. He seems to think that the fiberglass insulation for water lines that comes in a roll about 2" wide and is wrapped around the pipe in a spiral is a good option. For the record, I am opposed to it both due to the limited r value and the continuous seam that results. I am hoping to impress upon him the need for real steam pipe insulation.

Steamhead, there is a fairly large air vent located near the boiler, in close proximity to the Webster Boiler Return Trap. It appears to be of the same vintage as the Webster. I know that it vents at times as I can hear it. I will get better pictures the next time I am on-site. I must admit that there didn't appear to be many (if any) obvious dry returns overhead. Most of my returns plunge low and therefore would be wet returns as I understand it.

Jamie Hall

Carry on! Looks like you are heading in the right direction -- though with what may be a rather ingeniously knuckleheaded system.

On the insulation -- that spiral wrap stuff just won't do (it doesn't do much on water lines, either, but it makes folks feel better). You need the 1 inch stuff made for the application. That will help.

If you have no overhead dry returns left... then you are going to need nice healthy main venting at the ends of the mains.

SteamPupil

Jaime, as the saying goes, you can lead a horse to water... I'll definitely put more pressure on him to allow us to properly insulate the mains though!

I have to say, I'm glad I finally bought LAOSH. I've been reading it from the beginning and Dan does a fantastic job explaining things. I'm currently reading about how old-timers used check valves in a wet return before equalizer lines and the Hartford loop... and I'm questioning the two check valves on the condensate return line just before that inverted trap on this boiler. This boiler has a Hartford loop and equalizer line already. Regardless, I'll keep reading but I think I keep finding more questionable things with this install.

SteamPupil

A question. Dan references the 28" in the A dimension from the supply main to the boiler water line. Given my inverted trap that is well above the boiler water line should my A dimension be 28" from the supply main to the top of the inverted trap or would it still be measured from the main to the water line?

Edit: Further reading gave me my answer. My inverted trap (false waterline) changes my A dimension just as I thought. I can almost guarantee that I don't have 28" between the bottom of my problematic steam main and the top of my false waterline. I'll measure next time I'm on-site but it wouldn't surprise me if I have only 12" or so. I will also check to see if there is a reason for this inverted trap as a result of the other main return line as there are two returns that tee together from opposite parts of the house.

Steamhead

Those two check valves need to be there if the Return Trap is to work. Don't remove them. See chapter 15.

SteamPupil

Steamhead, thank you. Yes, I read chapter 15 after finishing chapter 5 or 6. However, I don't believe they are piped correctly. In the diagram in chapter 15 it shows vertical separation between them. It specifically shows the outward check valve at the water line (either boiler or false water line) and the inward check valve at a specific vertical distance below. Both of my check valves are in the same location vertically. They are both located just before the inverted trap begins its vertical rise. The only thing correct appears to be that the BRT is between them. Also, it shows wet returns bypassing the BRT but I believe that all my returns tie in before the BRT and due to the inverted trap wouldn't they all be considered wet? I'm not sure my lowest steam main (and the problem one at that) is above the top of the BRT either.

I've got a lot to check out when I get back to this job.

AMservices

Here's a brochure for your system showing the check valve piping

SteamCoffee

As you may know, almost all vapor systems had return devices that solved a huge problem in the coal burning days: fire control. Most all of these systems ran on a few ounces of pressure, just a small overage caused backups on the returns, causing boiler water level issues. Coal, especially bituminous, could be very hard to control with just draft regulation, it’s about all they had. A flare up in the coal bed could cause a temporary boiler pressure rise before the draft could tamed. Today, vaporstats can keep the pressure well in check, making them mostly obsolete, most boiler return traps fail due to them rarely being activated. Sounds like the rest of you issues are being addressed but the Webster R was a very nice system!

SteamPupil

I was able to swing by and get some more pictures yesterday. This was the first opportunity I had to upload them.























The BRT definitely appears to be piped generally the same as the Webster Type R that was linked above. The most glaring difference is that the false water line that was added is roughly in line with the middle of this BRT, but apparently it should be 4-6" below the BRT depending on which BRT is installed. This brochure mentions 40-15 through 40-160 but the label on this BRt rather clearly appears to have a 0 stamped followed by 23 cast. I'm assuming based on size it would be equivalent to a 40-25. Should I start by lowering the false water line so it is 4" below the BRT as in the brochure? BTW, I checked the check valves yesterday and they both appear to be in good working order with basically no mud.

I have also taken some pictures of my problem steam main including the two thermostatic steam traps installed. If you look closely in each picture I marked (on the nearby wood post and/or wall) where the false water line currently is at in relation.

The last picture is simply one of the other steam mains. It has an air valve. My problematic steam main does not. Should it?

AMservices

There is so much wrong here, it's hard to know where to start.
If it was my job, I would start by cutting out all the copper.
Copper expands more then steel, so soldiered joints will crack and leak.
Then I'd identify all the supply lines and all the return lines, then figure out a new piping layout to feed all the radiators and vent all the air back out through dry returns to the Webster air eliminator.
This was a naturally induced vacuum steam system. There should be only only be one vent in the system, found on top of the air eliminator.
The boiler should be piped with a 4" drop header and Thoroughly cleaned.
The radiators will need attention as well I'm sure.
So make sure your accounting for the T&M needed to fix supply valves and steam traps.
Steam is easy when you get to know it.
The art of steam piping is simply having the right size pipe, To carry how many BTU's you need to heat the radiators, at very low pressure ( ounces of pressure). Make sure all the condensate can get back to the boiler and never get trapped. Make sure all the air can get out and never get trapped.

The devil is in the details.

If you don't already have it, buy the" lost art of steam heat".
You will need it for all the questions you will ask yourself.

SteamPupil

Yeah, I'm not thrilled with the copper but I don't think I'm going to get the go-ahead to replace it. I've utilized a drop header when replacing a boiler before, is there a reason to limit it to 4" or is that just the minimum? I've already fixed most if not all of the radiator supply valves and return traps that were malfunctioning.

I want to make sure that I understand what makes a dry return dry vs a wet return wet. Is it simply the absence of steam? Obviously either could carry condensate.

I was suspicious that the air vents were not intended with this system. Is that to include the radiator air vents?

I've already purchased the Lost Art of Steam Heating as of Wednesday evening. I've currently read Chapters 1-6 and 15.

AMservices

@SteamPupil
Thank you for being part of the 1% in our industry that cares enough to ask the question and find the answers, rather then replacing with something more familiar this day and age.



Weil-maclin wants a 4" header on that boiler.

If there are leaks in the piping, they need to be fixed to get the benefits of a vacuum system or any system on that matter.
Copper can't do the job the way steel can.
With leaks your customer will be losing steam. That means losing energy, losing water that will need to be replenished. The water will drip on whatever's under it, potentially damaging other parts. Constantly needing fresh water will kill the boiler.
It will be a pay me now or pay me later situation.

Dry returns should only carry condensate, not steam.
Wet returns are full of water, usually found below the boilers water line, Unless there's a false water line.

Chapter 9 will tell you why the air vents don't belong on this type of 2 pipe steam system. With them you lose control.

Don't skip any chapter. Important information could be missed.

BobC

I know very little about Webster steam systems but all the info you need is in TLAOSH, Dan really deserves an award for writing that book. It has a tremendous amount of information and written in a way that is very easy to understand.

If there is anything you don't understand, the expertise on this board can not be beat and they are all willing to help you understand how these systems should be set up.

Bob

SteamPupil

I see now that you were referring to the offset header being 4" rather than a drop header (which would be nice to make sure the steam is completely dry) being installed.

While I would ultimately like to be able to fix all of the problems the reality is that I need to start somewhere. If I can solve the problem with the 2nd floor radiator that comes off that long steam main then I will have a greater chance of convincing him to allow us to repair everything.

I have water hammer in that line and it doesn't appear to be draining properly at the last thermostatic trap. Most of that return line is wet (in the picture I have it the false water line marked on the wall) due to the false water line at the boiler by the BRT and it is a horizontal distance of over 50'. The brochure that AMServices posted shows the water line being 4" below the BRT and instead it is about equal with the center of the BRT. The actual boiler water line is near the top of the check valves in the picture. Would it be unwise to start by lowering the false water line (I assume it is still needed to some degree since my boiler water line is not within 4" of the BRT) to match the brochure and see if that helps my last thermostatic trap to actually drain?

Jamie Hall

I'm looking at the picture just above here. I presume that that is the return line to which you are referring as "mostly wet"? A return which is mostly wet is also a problem. Returns have to be either wet -- at or well below the water line or false water line for their full length -- or dry -- well above the water line or false water line for their full length. Anything in between isn't going to work.

So the question is, was that pipe intended to be a wet return? in which case, where is the dry return which was associated with the steam main and thermostatic trap? Or was it intended to be a dry return? If it was intended to be dry, it may be that the thermostatic trap to which you refer was intended to be a crossover trap, which allows air but not steam to leave the steam main. But... in order to do that, the return must be dry, so the removed air can go to the central location and be vented.

And, incidentally, if it was a wet return, there should be no need for a trap on it -- if it's full of water, neither steam nor air can flow and mess things up...

AMservices

Start by fixing problems around the boiler. If the boiler can't dry steam, you will be spinning your wheels the rest of the way.

Identifying where You have horizontal return lines that are below "B" dimension. What is that false water line protecting?
When the system was 1st pipe, all of the return lines had to vent back to the air eliminator. That should be the lowest point of your dry returns. If there was a wet return originally installed, it would be for drips at the bottom of risers or low points in the steam main. The drips should drop straight down Into a wet return to drain back to the boiler.
Are there any apparent changes In the basement where you can see why they needed to change the steam piping?
Can it be put back without turning the world upside down?

How many radiators are in the house? How many are off the 1-1/2" main? Do you know what the EDR is of the system?
Try to figure out if that 85' of 1-1/2" is capable of carrying enough steam to the radiators.

When your standing in front of a problem radiator, you need to ask yourself "how is the steam getting in? How is the air getting out? How far does steam advance in the system? Where is there water hammer and at what point in the cycle? Is the boiler short cycling before the system is filled? Does the boiler run continuously during a call for heat?

Steam (like everything in nature) will always take the path of least resistance. The supply valves are your balance controls. Your steam traps are first your air vents.
Try convincing the steam to go where you need it to go.

Think like steam

SteamPupil

That return line would be dry if not for the false water line. Obviously, the false water line is not original and, aside from a possible misunderstanding of it being required for the BRT, seems unnecessary. At a minimum it is much higher than required or wanted and has a very negative impact on my B dimension.

I appreciate the advice that steam flows from high to low along the path of least resistance. I know that the radiator is not getting steam as a result of a water trap that forms before the thermostatic trap. I'm assuming the water doesn't drain due to my B dimension. I get water hammer in that steam line as it approaches the thermostatic trap as well.

If I understand correctly, a return can either be wet or dry. If you have thermostatic traps dumping into a line then it should remain dry otherwise the steam from a wet trap or drip would cause pressure on the return resulting in the thermostatic trap not functioning. Am I correct? If so, then this return line is clearly dry by design as it carries water from several other traps along the way. If I eliminated this trap and connected a drip from the steam main wouldn't it affect the other traps?

This is why I'm concerned with the false water line. I could fix everything with the header but if I can't drain my steam main trap then I'll never solve the water hammer and radiator not getting hot.

AMservices

You can't vent air through water so there needs to be a dry return that runs back to the main air vent.

AMservices

@SteamPupil, where is this job?

SteamPupil

AMservices, thank you. That's so obvious I don't know how I didn't see it. I haven't made it all the way through Dan's book yet either. So, could I add a pipe high off the the existing return just to carry the air back to the main air vent? The only other way I could eliminate my water trap in the return line would be to eliminate the inverted trap after the BRT but I think I might need it, just not at it's current height.

This job is in Owings Mills MD, a suburb of Baltimore.

Jamie Hall

Suburb of Baltimore? See if you can get @Steamhead to come out and take a look. It would be worth the time and money.

AMservices

Your welcome @SteamPupil
Now that you see the problem, you can fix it.
Yes, looking at the brochure Showing the dimensions of the return trap, check valves and air vent the boiler return trap needs to be 4" from the actual boiler water line, not a false water line.
From the looks of your pictures you have the air vent with the 1-1/4" drain, So that would be 15" above the water line.
Horizontal return lines will hammer if they're below the B dimension. Dry returns need to be free of steam, That's why all of the steam traps need to be working and you should have good working crossover or F & T traps at the ends of the mains.
Just as a steam trap works on the radiator, the crossover traps well vent the air from the mains to evenly distribute the steam to the run outs and risers.
If you can get all of the air to vent back through the Webster air eliminator, the air eliminator acts as a check valve that lets air out and holds a vacuum while the system is cooling.
While a vacuum is taking place, The boiling point of the water is dropping. Even though the flame is off on the boiler, the cast block is still very hot and will maintained a boil as the system is cooling.
A vapor vacuum system becomes self balancing under these conditions, Thanks to the same principles that gets the air out in the steam in. High pressure goes to low pressure always.
When the system is sinking into a vacuum, the vacuum pressure will be stronger in radiators that are in colder rooms.
When the system can run on a few ounces of pressure, steam will always favor those rooms And in the off cycle while steam is still vaporizing in the boiler.
The tighter you get the piping and the better you get the insulation, The better the system will perform.

You got this!

SteamPupil

@AMservices
I have attached a better quality copy of the Webster Type R brochure page. I thought you might be able to use it in the future.

Steamhead

@SteamPupil , check your PM.