Steam Boiler -- Basement Level not Heating

Alchemist

Hi all,



I have a small condo complex (5 units) in Minneapolis. We were having all kinds of problems with poor heat (and distribution), water hammer, etc. All the usual problems I suppose. I had a steam guy come out and put in vents on all the mains (except the one to the basement unit). This took care of all the problems in 4 out of the 5 units. They heated quickly and well, were quiet, and everyone was happy. FYI, there is a condensate return tank/boiler feed pump (vertical shipco) now that wasn't there before boiler replacement.



EXCEPT, the lady in the basement level condo. Hers has the only wet return in the building. The radiators are above the boiler level, but obviously at a much lower level than the rest of the building. In fact, the radiators are mounted on the upper half of the walls. The "out" side of the radiators feed up initially before joining together and entering the wet return which runs under concrete back to the boiler room. I think the beginning of the return line is actually above the boiler/return tank water level and shipco tank inlet level, but drops to about 2-3 feet below it before trying to return up to the tanks.



Her unit is barely heating at all. We're talking the other units holding a steady 74 degrees round the clock while her unit barely gets up to 60 degrees.



Does anyone have a thought on what might be causing this? Or any thoughts on potential solutions? Is there any way to vent her main? It worked well at one point in time!!



Thanks in advance for any thoughts/advice,

Casey

SWEI

It worked well at one point in time

When was that?  By any chance has the boiler been replaced since it was working well?

Alchemist

Boiler Replaced

Yes, the boiler was replaced about 3 years ago. Truthfully, we haven't had the place much longer than that, so I can't speak personally to the fact that that unit heated well before. Since the boiler replacement, the heating situation had gotten slowly worse over the course of the 3 years. However, even though there were a lot of problems, prior to the vents being put in, that unit was apparently heating well enough (the rest of the problems -- water hammer-- not withstanding). At least as well as the other units.



The vents being put in were the big change that altered things, without a doubt.



Thanks,

Casey

nicholas bonham-carter

Cold basement

Is this 1-pipe or 2-pipe steam?

Can you follow the steam mains, and find where the pipe goes cold on it's way to this basement area?

If the pressure is too high (over 18 ounces) , then the returns could be backing up with water, so as to prevent the air from escaping in this basement loop.

Are you the developer, or merely one of the new condo owners left holding the bag?

Post some pictures of the boiler, and it's piping, so we could see if excess water is being thrown up into the mains, and returns, exacerbating this basement problem.--NBC

Alchemist

one of the new condo owners left holding the bag

It's a 2-pipe system. Right now the pressuretrol is set at 2 psi.



I simply own one unit in the building, but seem to have been nominated as building manager (at least that's the way it is working out!!)/



Anyway, when the boiler is fired up (we overrode it to about 76) the pipes get hot right up to the radiators, just not as quickly as the rest of the building (presumably). The radiators themselves varied in how hot they got and how long it took them to get there.



You said,



"...the returns could be backing up with water, so as to prevent the air from escaping in this basement loop"



I have a good hunch that it is something exactly like this that is happening. Could it be as simple as just taking down the pressure even lower?



As an aside to that, the guy did say that this was probably an old "vapor" system (so needs ultra low pressure settings?).



Why do you suppose the unit stopped heating much After the other main vents were put in?



Thanks!

Casey

Alchemist

More info

This is some information I got via email from the last time our steam guy came out? I wasn't there, but got this information from the lady who owns the basement unit.



"He said he wants to find a solution to the situation at hand, which may

be installing a small tank to collect the water that's building up in my

unit. He said I'm at the end of the system, so a lot of water builds up

under my unit and sits there."



The concern I have is it's an expensive job and I want to know for sure that it is necessary and right thing to do?



thanks,

Casey

nicholas bonham-carter

It's a tough job, but someone has to do it!

Is the system now a gravity return?, meaning no condensate tank is collecting the water coming back from the returns, and then being pumped into the boiler? If so make plans to remove it and make it the gravity system it was when first installed.

If the originall installer would have suggested a tank under your unit, because it's the end of the line, he would have been shown the door. The job at hand is to return the system to its original sttae of operation. There may have been some subsidence at your end, altering the slope of the pipes, and interfering with the steam flow, and it's just a matter of doing some observation, and undoing the deferred maintenance.

I suggest you get the collection of steam books from the store here, and you will soon be able to understand why that suggested Kludge is not the answer.

Your 2-pipe system was probably the Cadillack, or even Rolls-Royce of heating systems, and has been neglected, and not working properly.

Luckily, these systems are so resilient as to be able to be brought back to their original state of operation, without too much trouble. Post some pictures here of your boiler, and it's piping, and we will advise.--NBC

Alchemist

Condensate Return Tank

There is in fact a condensate return tank. I don't know if there was one prior to the new boiler being put in. The previous boiler was estimated to be maybe ~50 years old...so circa 1960. The building was built in 1911.



I will get some pictures up the next time I get a chance to get over there (I don't live there; actually rent out my unit).



Thanks for the info,

Casey



Should I turn down the pressure, in the meantime?

nicholas bonham-carter

Turning Down the pressure

What is it now?

This system may have been designed long ago to work on 2 ounces!--NBC

Alchemist

Pressure Now

Is set at 2 PSI.



It would be easy enough to stop by tomorrow, turn down the pressure, and get some pics.

nicholas bonham-carter

Pictures essential

While you are at it, measure the height of the radiators above the floor, and therefore their height above the water-level of the boiler.

2 psi is enough pressure to raise the condensate level 42 inches in the returns of a gravity return system (which you don't have). This may be why the condensate feed tank was put in as a bandaid to a chronic over-pressure, and if not installed right, may be part of the problem. An accurate 0-3 psi gauge would show you better what is happening.

Remember the system worked well when new, and the job is to return it to that state now.--NBC

Alchemist

Pictures Coming

But first, I adjusted the pressure of the vaporstat.



It was set at 22 ounces cut-out and 16 ounces cut-in!! I assume this was completely wrong!!



if I understand it right, subtractive vaporstat was set at 1.75psi (main) and ~5 ounces (differential). This makes no sense, right?



Anyway, it is now set to 1.5 psi (main) and 16 ounces (differential). I believe that is an appropriate setting (if any could confirm that would be great) and we will see what happens.



Pictures in a few minutes once I get them loaded.



Caseys

Alchemist

Pictures of System

Here are pics of everything in the boiler room.

Let me know if you can't open them.



Notes: Sorry, pics are no longer in this order



-Vaporstat with new adjusted settings

-Boiler and main-- some near boiler piping

-Condensate return and feeder pump

-View of boiler from perspective of bottom of radiators on problem basement level

      ** My guess is bottom of radiators are at least 5-6 feet above boiler water level- -Near boiler piping on condensate return side

-Main and return from one side of building -- south (no problems on that side).

  ** Our guy had initially put a vent on upper joint of black piping (but removed for some reason now?)

-Top of boiler, main

-Main & return from north side of building (2 units). New vent installed here on inlet side of trap (F&T ?). Adding this vent seemed to help the 4 upper units considerable and quieted the water hammer.

-North returns (again upper left where vent was removed?)

-Wet return running to condensate tank from problem (basement level) unit

-Vaporstat at my new adjusted settings. 

***I found it with main (1.75 psi) and differential 4-5 ounces). This had to be wrong, didn't it??



Thanks for all feedback/help (especially NBC!!)

Casey

Alchemist

Pictures

Please take a look at other posts and pictures below. I am a little bit desperate to get this figured out!!

Pumpguy

Don't know if I can....

shed much light here, but that blue vertical tank and pump assembly is a Shipco boiler feed unit with a float operated low water make up. 



Typically, these boiler feed units are installed on 2 pipe systems when a new boiler is installed that doesn't have the water storage capacity of it's predecessor.  The thought is that the new boiler could run out of water before the building was filled with steam and condensate started coming back. 



My question would be, how does the returning condensate get into this boiler feed receiver?  On these vertical tanks, the inlet is up high, and we may have a water seal in the return piping that has to be overcome before the loop is completed.  If that's the case, the basement return lines may not be draining properly. 

Alchemist

Boiler Feed Pump

How does the water from the wet return line get into the receiver? Good question!!



The wet return does meet with the other dry returns at a junction below the receiver inlet.

The make-up is float-operated as you pointed out.



At one point, we did have a huge problem with too much water in the system. I'm not sure exactly what fixed that. One guy replaced the F&T trap shown in the pictures. The last guy vented one of the mains. The venting seemed to be the key that helped.



The Shipco tank usually sits at about 1/4 full (just above the make-up line). The boiler water level is right dead center or just slightly below the half-way mark on the site-glass. So no real problems there.



But how could I figure out if the water is returning properly from the basement unit? If there is a "water seal" in the return piping, how on earth would I go about dealing with that?!



Anyway, there is either water backing up into that unit or there is air that isn't getting out. I suppose it's as simple as that!! But how to fix?!



I am contractor number 3, with a second (4th) opinion coming next week from a "steam boiler expert." hah!! We'll see.



Anyway,  thanks for the thoughts.



Casey

Pumpguy

Casey.....

The first question to answer is, are the lowest traps in the basement at, or above, the inlet to the Shipco boiler feed receiver? 



If yes, then the answer to your question is with a piping arrangement called a DOOR LOOP.  This is illustrated at the bottom of page 95 of Dan Holohan's book THE LOST ART OF STEAM HEATING. 



With a door loop piping set-up, instead of piping over or under an obstruction, you use a pair of tees and pipe both over and under the obstruction.  In your case, the obstruction is the space between the lowest trap and the inlet to the Shipco tank.  This allows the water to flow by gravity downstream, and the air is carried through the overhead loop so there's no head to overcome. 



Sorry, I'm not savvy enough to post an illustration here, but you can find this online.  My website www.nashjenningspumps.com has an illustration in the solutions

 section. 

                                                    ____________

                                                    I                      I

A door loop looks like this:  -------I                      I-------------------->

                                                    I                      I

                                                    --------------------

Now, if the lowest trap is below the inlet to the Shipco tank, well that's a problem since water does not flow uphill.  Being a pump guy, my suggestion would be to have these low traps drain into a small receiver with a condensate pump and pump the condensate over to to the Shipco tank.  Another way would be with a vacuum pump, but your's is not a vacuum system so that's out. 



I hope others here can come up with some other way to get the water back, but however it's done, there needs to be enough pressure to push the water up into the inlet of that Shipco tank. 



It's a shame you have the vertical version, because Shipco makes this in a horizontal version too with a lower inlet. 



I've been told Will Rogers said "Solutions cause problems" and this appears to be a situation where the building needed a new boiler, the new boiler needed a boiler feed package, and the boiler feed tank is keeping the return lines from draining properly.



Hope this is of some help.



Good luck.

Alchemist

Traps Above Shipco Inlet

I believe. The main feeds the radiators from above in the basement unit. The radiator outlet sides join together and eventually drop into a crawl space right below that unit before they make their run back to the boiler room. I think that the beginning of that wet return is above the level of the shipco inlet, so there shouldn't be any traps below the level of the inlet.



To help my fairly ignorant overall knowledge, what kind (and where) of traps would I be looking for (besides the steam traps on radiators)?



That being said, I am completely convinced now after reading everyone's post that the water is not able to drain properly from that unit. How would there be enough pressure from that wet return to push enough condensate (once the return joins with the dry returns) up into the tank. For that matter, would the pressure from the other returns (since they all come together at one junction) cause even more push back against that wet return trying to get back to the tank?



You said:



"Being a pump guy, my suggestion would be to have these low traps drain

into a small receiver with a condensate pump and pump the condensate

over to to the Shipco tank."



That is exactly what has been proposed by our guy. Maybe that is what needs to be done.



Hopefully more people will weigh in with their opinions!!



I appreciate yours (and everyone's) input and thoughts.



Casey

Alchemist

Pressure change failed

The owner reported that her unit this morning is 57 degrees (is currently not receiving any heat) and reached a peak of 63 degrees overnight.



The odd pressure setting from our boiler guys was actually working better for her unit (her unit was starting to get up around 65 degrees-compared to 74 in other units--on a somewhat regular basis.



So I will go and set the vaporstat back to where it was for now.



Casey

Alchemist

Wet return changed to Dry return possible??

Well, my adjustment to the vaporstat made things worse in the basement unit. My guess is that the guy who set the high cut-in was trying to increase the pressure that would hit her system (otherwise, at super low pressure, wouldn't the steam go the places of lowest resistance--ie the other units upstairs with dry returns--and not send much steam to her unit in basement). That's my guess, and I think the higher pressure shouldn't cause any condensate to back up into her unit since there is a shipco return tank/boiler feed pump?



Also, this is a shot in the dark. But might it possible to convert her wet return to a dry return? I'll have to see the piping arrangement much closer, but, as much as I've seen, the main runs above her unit with only slight drops to the radiators (whose outlet side returns up above--at about the level of the main) before connecting and dropping below the unit to feed the wet return. By eyeballing it, I think the beginning of the return is probably above the return tank's inlet and the end of the return is about 2-3 feet below it. This seems, in theory, to maybe create enough water "weight" to move the water up into the tank (though apparently that is not happening). I have no idea of the height above (or amount of drop) that would be required to move this condensate?



My idea: Since the main runs above the unit (through an easily removable ceiling to the hallway leading to her unit), and since the outlet sides (and bottoms of the radiator) sit well above the boiler/return tanks water lines and inlet to shipco tank, might not it be possible to re-pipe the return parallel to the main (if there is room) and return the condensate in a dry return (thus potentially alleviating the problem)?



Maybe this is the dumbest idea in the world!! But please remember that I am a complete novice and have only finished 1 and 1/2 of Holohan's books.



Thoughts??!!



Thanks so much,

Casey

Pumpguy

Any time....

a condensate line runs uphill, a pressure differential equal to the height of the water column is needed to move that condensate uphill.  One PSI will lift water 2.31 feet.  This can come from the steam pressure on the steam side of the trap, a vacuum on the return line, or mechanically from a pump.



Since you want the freest possible drainage from the basement traps, and should also want to heat with the lowest possible steam pressure, using steam pressure to push the condensate uphill is the worst way to do it. 



Since the boiler feed tank inlet is below the lowest trap, the door loop piping arrangement is probably your best bet.  You can leave the existing wet return line to allow a gravity drain to the tank, and pipe an overhead dry return for air venting and remove the need for back pressure to push the condensate uphill.

Alchemist

Clarification (& Thanks)

I appreciate all the good information you've provided. I just need a couple points to be clarification (for my novice brain) before I chat with our steam guy.



You said:     "With a door loop piping set-up, instead of piping over or under an

obstruction, you use a pair of tees and pipe both over and under the

obstruction.  In your case, the obstruction is the space between the

lowest trap and the inlet to the Shipco tank.  This allows the water to

flow by gravity downstream, and the air is carried through the overhead

loop so there's no head to overcome."



I read pg 95 in Holohan's book and looked at your diagrams in descriptions on you website solutions page to try to wrap my head around this.



So...by piping in a dry return (and leaving the wet return in place), this will change the dynamic so that the water moves more easily into the tank. I'm having a bit of a hard time visualizing this. I think I get that the air/steam moves automatically into the higher (dry) return (thus alleviating that push back in the wet return line). Still, doesn't there need to be some pressure (as you indicated 1 psi moves condensate up 2.31 feet)? In this piping arrangement, where does the pressure come from and/or why does the condensate then move more easily uphill into the tank inlet?



Appreciate your thoughts,,

Casey

nicholas bonham-carter

Piping around the ship co?

Can you pipe the returns as a gravity return, and do without the ship co?

When first installed, the system was probably that way.--NBC

quack24

water level

I'm not sure I understand the layout of the system but if it was a gravity returm wouldn't theradiator have to be 30 inches from top of the water line to the bottom of the radiator or else the water will back up into it?

Alchemist

I don't think so..

This boiler runs with much less water. My fear would be having it run dry before completing the cycle. The boiler feed line runs quite a lot while the boiler is running.



I'm trying figure out how I could put in a "door loop" as pump guy has suggested. I'm trying to understand the how and why of it, but he seems very confident that it would make a big difference.  I'm also trying to figure out where. Based on the overall layout, I don't think we can put in a dry return that runs all the way from her unit (a really long "door loop").  But maybe that's not even what he is suggesting.



Can one of these loops be put in at some junction in the wet return? Does that even make sense?!! I'm thinking there must still be a lot of air in the wet return (where else could it go) and perhaps one of these loops vented could relieve some of that back pressure (thus allowing to make the climb into the shipco inlet more easily).



Who knows!!



I love all you thoughts and ideas. I appreciate it greatly. It's challenging, frustrating, and sometimes very satisfying trying to understand think through this problem.



Casey

quack24

door loop

I'm not either sure I understood where he wants to put it. My question was in response to NBC's sugesstion on making it a gravity return

Alchemist

Don't think

we can return it to a gravity return. See post above.



One option, though maybe not ideal, is to put a collecting tank at the end of the problem unit and pump the water back to the shipco tank. Short of any better ideas, this seems to be what our guy wants to do (I do have another guy with credentials and good reputation coming for a second opinion). Presumably, the pump would provide the needed pressure to get the water out of her unit and move it to the condensate tank.



Who knows. I'd really like to know if putting one of these door loops on a wet return and venting it would make a difference (or if I'm even understanding the idea correctly).



Casey

quack24

air vent

I know it sounds a little knucleheaded but wouldn't an air vent in the radiator be a cheap solution

quack24

door loop

I'm pretty sure door loops go on the mains or dry return and not on wet returns the idea is that you take the condinsate through the bottom pipe and the Steam through the top pipe

Alchemist

I thought so too..

But  pumpguy seemed to be suggesting otherwise...or else I misunderstood him. I think he said condensate through bottom loop and air through top loop.

quack24

door loop

Air/steam its the same thing (sort of)

Alchemist

Funny you should say that..

Our steam guy did put a vent somewhere near a radiator in her unit (I haven't seen exactly where as I wasn't there). It helped the temp somewhat, but she says it's way too loud to be a permanent fix. There just doesn't seem to be any good place to vent the dang thing. 

Alchemist

I guess he said

the door loop would go somewhere between the lowest trap and the level of the shipco tank inlet. Maybe it's considered a dry return until it drops below that point?

quack24

air vent

What kind of noise if it was like a whole lot of air coming out too quickly it was probably venting too fast try a slower vent

quack24

water seal

I'm not sure if this makes sense or not but if you have a wet return on a radiator with no vent there is no way the steam can get in. You gotta let the air out so the steam can get in either through an air vent or a steam trap that goes to a vented dry return you can also try venting one of the traps downstream from that unit if you have the ones with the extra tappings in them

Alchemist

Yeah

I will ask about this.

Alchemist

Radiators...

are well above boiler. They have proper steam traps and start as dry returns. The problem is the piping. It is inaccessible at almost every point.

quack24

i must have missed the

Post that said they were 5-6 feet higher but think you still need to vent the dry returns before they become wet I'm sure someone will correct me if I am wrong

quack24

maybe im not so sure anymore

Look at page 136 in the lost art seems something like that is happening by you

Pumpguy

The real issue...

is if there is any uphill piping in the return lines draining the basement radiators' traps?  If there is, this will form a water seal in these lines, prevent the air from being vented, and require an upstream pressure to displace the upflow water column. 



If these traps had a simple downhill run of return line piping, the air and condensate would flow freely to the boiler feed receiver.  The air would vent to atmosphere at the boiler feed tank's vent connection, and the condensate would be collected to feed the boiler. 



The door loop arrangement would allow the same thing to occur.  Each of the basement radiators' traps would discharge into the horizontal branch of a tee.  The lower connection of the tee would be connected to the existing return line to form a wet return.  The upper connection of the tee would be the dry return and carry the air overhead.  All of these dry returns would be connected together at the upper connection of a tee at the boiler feed receiver's inlet connection.  The lower connection of this tee would be connected to the existing wet return. 



A door loop functions due to water seeking it's own level, same as a water level.  Add a certain amount of water to the upstream tee of a door loop and the downstream side will rise by that same amount.  Position the downstream tee slightly lower, and Wallah!, we have flow of that same amount. 



I have seen whole buildings piped using this door loop arrangement.  This allows slab-on-grade construction, of a school for example, without needing a basement for the boilers, pumps, etc.



As I said in my initial post, you could have these low traps drain into a small condensate receiver.  The air would be vented at this receiver's air vent connection, and the condensate pumped over to the boiler feed receiver.  But you would need to run piping anyway, so why not use a door loop piping arrangement instead, and eliminate the pump? 



You could also solve this problem with a vacuum pump, and I could tell you how to do that too 'cause that's my specialty, but I don't think you want that added expense and complication. 



Please keep us posted as to how you finally solve this problem.  Just remember, water does not flow uphill. 

quack24

water flowing uphill

I'm not sure I'm understanding correctly but even if the return went up and down the water will seek its own level (plus the steam pressure) so as long as it doesn't go higher than the radiator at any point the water should make it to the feed pump the only problem is you have air trapped between the steam and the water so the steam will just compress the air but never fully fill the radiator (I'm no pro I'm just trying to understand how steam works) please correct me or explain where I'm going wrong