Steam boiler, common drain

Luv'nsteam

In the installation of my new steam boiler, because it would make draining and controlling the flow of hot water easier, I would like to plumb all drains and the pressure valve into a common drain pipe. 



I have five lines I would like to plumb together:

1) Wet-return drain/clean-out;

2) Boiler mud-leg drain/clean-out;

3) Skim valve drain (it is installed and will remain installed);

4) LWCO, probe-type drain/clean-out; and

5) Pressure valve outlet pipe will be plumbed into the end of the drain in case it ever blows.  All pipe will  be properly supported from above with threaded rod and pipe hangers, providing some movement for expanding pipes because of heat and/or pressure.



Also, except for the pressure valve outlet, which will not have any restrictions, all drains have their own ball valve before being brought into the common drain pipe.  The common pipe is 1 1/4" black, which is also the tapping size for boiler drains.



Is there any problem with doing this or anything I need pay special attention to assembling this?  The final drain in my floor is in the next room and there is a trough in the floor and hole though the wall.  My drain pipe will end with a 90* ell directing the drain water or pressure relief into the hole, parallel to the trough.



Does my description make sense?



Does anybody see any problems with plumbing all of this together?



Any other thoughts/suggestions?





Thank you,



Mike

Jean-David Beyer

I am not a professsional, so keep that in mind.

You probably should pipe all relief valves to drains separately. If not, pressure induced by one opening can cause problems elsewhere on the common drain pipe. I do not know plumbing codes, although I did read the New York City code book for some time in the 1800s. Fascinating. Even told you how to make illuminating gas with a large bellows and an in-ground gasoline tank.  But you better check with you local codes and plumbing inspector.

crash2009

A Blowdown Tank

may be necesary in your city.  The tank cools the water prior to discharge into the residential drain.

Luv'nsteam

Common drain

A cooling tank does not sound like all that bad of an idea, however, the trough in the 'crete floor goes to a floor drain, not public sewer or septic/sand mound.



As for pressure from one drain affecting another, I THINK it will be OK.  The way I am thinking of doing it is thus:

from behind the boiler, the wet-return is piped to the left side and then comes forward with proper pitch down.  Thereafter, a ball valve will be installed. 

After the valve, a tee, into which the ball-valved mud leg will be plumbed.  After that, another tee. 

Into this tee will be plumbed the drain from the skim port and of course, a ball valve will be between the skim port and drain tee. 

Next, another tee and this will be plumbed from the LWCO, which also has a valve. 

Of important note, all the aforementioned tee's will be horizontally located for connecting drain pipe. 

And the last tee will be for the pressure relief valve piping.  This tee will be located so pressure valve pipe is coming in vertically, and of course, no valve. 



So, the drain pipe from the wet-return will be in a straight line along with all tee's.  All tee's except pressure valve tee will be located horizontally and last tee will be positioned vertically for the pressure valve pipe.  In my mind's eye, I see each drain flowing in a straight path until the last 90*, which is needed to direct the flow though the wall, into the floor trough.  No matter what is draining, because a) the other valves are closed and b) there is air in each pipe, I do not see the drain water from one connection going to far, if at all, into another drain pipe - water cannot go where air is in the way.  As for any water making up the pressure relief valve pipe, partially because it is located vertically and high above the main drain pipe and also because it is filled with air, it to will not allow any water to flow against the valve.  And to keep the minimum of restriction against any pressure that may be released, the pressure valve is plumbed dead last in line in the drain pipe and closest to the exit.



Does that make sense? 



Can you think of any strength/stress issues with this setup?



Boilerpro, Steamhead, any other pros reading this?  While I am open to all/any suggestions, I would truly like to hear from one or more of the pros who make their living doing this work, particularly if anything like this has failed in the past and if so, why do think or what do you know caused the failure?



Thank you to all,

Mike

crash2009

A while back

 I was thinking about installing exactly the same thing you propose.  Unlike you, all I have is a floor drain which connects to our city sewer system.  I was advised to install a blowdown separator to lower the temperature of the condensate prior to dumping down the city drain.

What kind of a floor drain do you have?  Where does it drain to?  Is it like the old boiler pits that drain to nowhere? 

Ron Jr._3

We did just that

on a big steamer last year . Teed in the relief valve , 2 purge stations for returns , the float LWCO and the boiler drain . It all dumped into a pit in front of the boiler , not connected to any sewer system . The pipe is sized to the boiler relief valve .  

Charlie from wmass

Not sure where you are

But in Mass we can not do that. Relief valves must be single lines to discharge the last time I had to look it up as if you are using the pipe for any other reason and the relief valve goes off the discharge pipe will be too small. Also individual pipes make find the source of the leak easier. I know it seems to waste pipe but you will not know if it is the boiler drain or the relief valve that is dripping. JMHO. Also always keep your first fitting 24" above your normal water line even if you use a drop header.

bill_105

Dear JDB

You may not be a Professional, but seem like a pretty sharp guy. But, in just what part of the 1800's were you reading this in??:) Fascinating!

I know - just a play on words

Jean-David Beyer

;-)

"But, in just what part of the 1800's were you reading this in??:) Fascinating!



I know - just a play on words"



All kidding aside, I was visiting a friend in Olympia Washington, and she had found a printed copy of the NYC plumbing code from the 1800s sometime. But I was probably reading it in the very early 1970s. I do not remember where she got it. But she has broad interests and abilities. By profession, she is a psychologist, but was an occupational therapist before that. As an OT, she knew lots of different skills. One time when I was visiting her, we ripped out the floor in her downstairs bathroom (that also had the washer and dryer in it) and installed ceramic tile. She even rented a gizmo like a circular table saw, but for tiles. It sprayed water at the cutting surface to cool the blade and keep down the dust. We also took out the old hot water heater and installed a gas one. We did everything but the gas. Actually we did most of the gas, but got a licensed plumber to check it all out before the inspector came.



Anyway, somewhere in her travels she came by that book -- obviously used. It was not a reprint. Absolutely fascinating. A whole section on how to run gas pipes for the lighting (must not accidently have traps), how chandeliers of gas lamps work that you can pull up and down (joints are water trapped so the gas does not come out the slip joints), how to make gas from gasoline (gas was not available to most houses at the time). There was some on water supply, and a lot on sewage and venting of sewer lines. In those days you need  an outside vent at the bottom to let air in as well as the one at the top to let the sewer gas out. We also had those in Buffalo, NY, but not here where I live in New Jersey.

Luv'nsteam

Drain pit

The drain in my basement is currently a dry well: a large pit filled with stone and the floor drain leads into it.  The floor is created above this and the home is built around it.  My home was built in 1887 when homes were built well (my walls are nearly 18" thick, masonry!).



Anyway, for now this will be where the boiler drain water leads.  I will likely cut a hole where the drain pipe is located, line it with terracotta and drop in a sump pump, because after more than 100 years of use, the stones are covered with silt and drain slowly.  Before doing this, however, I will certainly need to add a cold water supply to lower drain water temp to avoid damage to the pump or a blow-down tank.  I am not familiar with an affordable sump pump that can handle a few hundred degree water.  : )



After proof reading this, I may just create a stone filled hole next to the boiler in order to avoid any additional engineering or materials.  Time will tell.

What does a blow-down tank look like?  Is this just a storage tank where the water cools before going into the drain?



Thank you,



Mike

Luv'nsteam

Pressure valve piping

Per the instructions that came with the valve, the piped outlet cannot be smaller then the thread size (3/4"), pipe must be supported and it must be kept as short as possible while being plumbed away from the boiler and walls.



The tapping on the boiler for the drains is 1 1/4" and this is the size of my common drain pipe.  While I was going to stick with 3/4" pipe from the pressure valve, I was bringing it into the drain with a reducing tee and at the end of the common drain.  My thoughts on this are to simply keep the pressurized steam under control and directed.  I am fairly certain it would blast the parging off my walls if it hit it (the valve is about 20" from the wall, so maybe it wouldn't hurt it).  The total length of pipe from the valve outlet to the reducer tee is a few feet but only has one ell and will enter the tee with a 45* fitting, thus eliminating one ell.



I am considering using a larger diameter pipe on the pressure valve outlet, as I see the pressure being reduced if passing from 3/4" pipe into say, 1 1/4" pipe.  But maybe not - the folks who made the valve determined that 3/4" was OK, so who am I to say they are wrong??

My first fitting is actually about 26" above the water line.  Also, because I did not know better (until I read Greening Steam), my riser is the same diameter as the header - 4".  It's a monster!



Thanks,

Mike

crash2009

It looks like this

and it works like that.  Here is a shortcut to one of many manufacturers.  http://cleanboiler.org/Eff_Improve/Operations/Blowdown.asp

Ron Jr._3

I thought

that was the main reason to use a drop header ........



If your mains are lower than the 24 inch minimum , that is ......... 



We were over the 24 inch threshold before we dropped the header . Worked amazing this brutal winter . Had one zone valve stuck open , but that might've been broken before the install . I'll have to check the code for common relief valve piping but it's just overkill to have 5 or 6 different pipes running along the floor ......... What about adding a tee in the vertical run of the relief valve and a goose neck pipe arrangement ( like an upside down trap ) out of the bull of the tee , lower than the relief valve ? So in the extreme off-chance of the relief popping while something else is discharging , the excess water could go up the goose neck then down into a bucket or something ?  



  

Luv'nsteam

Blowdown seperator

That's pretty cool, Crash2009.  Thank you for sharing.  I will keep it in mind, but for now, I don't think I need it.



Thanks,



Mike

Luv'nsteam

IF I understand correctly,

The drop header does indeed, help dry out the steam, it provides swing joints for expansion and offers room for hooking up the mains if head room is minor.  The MFG's instructions call for a 24" riser in the tapping, measured from the water line and Dan suggests measuring from the top of the boiler (that's what I did).  That also helps dry out the steam by allowing gravity to pull the water droplets back down before the steam enters the header.



However, in TLAOSH, Dan provides the math to finger out the velocity of the exiting steam, as well as the "Dead Man standard" of 15 feet per second (the book is not in front of me nor are my notes, so if that is wrong, please correct me).  After I crunched the numbers for my boiler, the exiting steam was traveling at a much higher velocity than what Dan shared (I think it was around 30fps).  My boiler has a 2" tapping and if I used a 3" header, the velocity would drop to, I think it was, 17 fps, which I thought was acceptable.  When I priced the 3", it was VERY expensive.  4" pipe was not cheap, but cost much less and the velocity dropped to something like .01fps, very slow indeed and very dry, too, so that's what I used.  I also found all the header parts in a scrap yard for less than $150.00 and most were new.  I love a good deal!



Thank you,



Mike

Luv'nsteam

Ron, is that two

Vaporstats I see?  Whats the purpose for two (if that is two)?



Thanks,

Mike

Ron Jr._3

They're all pressuretrols

3 were used on this install . One was manual reset I believe . One might've been used to cycle the low / high fire . It's been a while .......  

Luv'nsteam

Interesting

Two look just like the vaporstat I'm installing on my boiler and the third (on the far right) looks like the pressuretrol that came with it (I'm also using that too, but for blowdown pressure).  Cool.



Thanks,

Mike

Charlie from wmass

The 24" height is for the first fitting above the water line

Dan as stated below recommends going from the top of the jacket just to be sure. The drop header is to then bring the steam back down after the riser. The idea is to get it high, drop out the water carried along with the steam then drop the dry steam to reach the supply piping. In Mass no traps or other items are allowed. If you want to join multiple discharges you can use air gaps at each point then use a common pipe sized to take the discharge of the combined output. That may be 2" pipe when all is figured. Redundent works when it comes to safety items. That's why you have multiple pressure-trols on that boiler.

Luv'nsteam

Charlie, I do not

Understand what you mean by "air gaps" with the discharge pipe. 



 As for safety, I am a firm believer in redundancy and have included passive and active controls with that in mind.



When you say no traps or other things, does that include valves or unions, as well?  If so, why?  I mean, what is the potential problem with either if these devices in the mains?



Thanks,

Mike

Charlie from wmass

Mike here is a link to an air gap

http://www.watts.com/pages/_products_details.asp?pid=312

these are used to allow for draining without a solid connection that could lead to backflow from the drain and in worse case scenarios lack of discharge due to blockage of the drain.

Ron Jr._3

I've asked a few times

over the years about how far you can drop a header . I guess the top of the boiler jacket could be considered a good rule of thumb , but some boiler jackets sit MUCH higher than the boiler block . Like the V9 . Some sit almost right on top of the iron . I wish Noel Murdough was still posting here . He opened our eyes and basically started this drop header craze a decade ago and guys like me and Mad Dog and Steamhead ran with it   

Charlie from wmass

Dropping is fine.

It is the first turn tat is the important figure. Up 24" then go low. I am not concerned with how low one goes. As long as it is above the waterline enough for it to drain well. If the first bend is too low above the water line then water can be carried over into the system.