Steam newbie with some questions-boiler short cycling/main venting/etc

a2shutt

Hi, I just added a 7 unit apartment building here in Michigan to my rental property portfolio. It's the first building I've owned with steam heat, so I've been frantically trying to learn steam over the past week or so! It seems like an incredible system and I'm loving learning about it. The boiler is a Burnham installed in 2007.



My first question- I've been working in the basement and noticed that the boiler seems to be short cycling. It seems to be random...it fires up for 20 seconds, then shuts off. A while later it runs for 3 minutes, then shuts off again. This just keeps happening...there doesn't seem to be any rhythm to its cycles. Where do I start for diagnosing this problem?



Second- one tenant (in the furthest apartment from the boiler) was complaining about intermittent heat and cold. I checked her radiators, and they all seemed fine. They had adjustable vents all set at the highest setting. What could her problem be? Do those air vents ever work intermittently, or do they just go bad?



Third- when I bought the building, all of the air vents on the radiators in the apartment with the thermostat were upside down (off). Would there be a reason for this? I flipped them all so that they vent now, but I'm not sure if that was best. The apartment seemed to be warm enough even without the vents open.



Lastly-there seems to be some sort of a return line, even though this is a one-pipe system. It's 2.5" pipe, then steps down to 2" as it gets closer to the boiler. It runs just under the basement floor, in a concrete trench so that it can be accessed. There are multiple lines feeding into it. It ends back at the boiler, but the line is run about 18" below the floor (like I mentioned) and there isn't any sort of pump to get the condensate (if that is the purpose) back up into the boiler. What is this line for? I can't really imagine it doing anything. Oh, and the only main vents I can find (2 of them) are on this line.



I can post pics of any of this on request.



My furnace guy claims to know steam (and he DOES seem to be knowledgeable), but he was getting confused between the radiator air vents and steam traps. I'm not sure whether to trust him or not.



Thanks for all your help-I'm sure this won't be my last question!



Aaron

Abracadabra

...

#1 - You need to turn off.  A safety? Pressuretrol? Water dropping low? What's the pressure? 

#2 - I never (rarely) believe what a tenant tells me.  Are all radiators in her apartment getting hot evenly with the rest of the radiators in the apartment?  A temperature logger like this: http://www.amazon.com/Extech-TH10-Temperature-USB-Datalogger/dp/accessories/B0026JHXQM is invaluable in tracking exactly what the temperature is in a multi-unit property.

#3 - Usually you want to vent the radiators in the apartment with the thermostat real slow so that you make sure that the rest of the units have gotten heat. Sounds like they took the cheap way out to slow down the venting there.  Actually, upside down, the vents should not vent at all and you will basically be overheating the rest of the building.

#4 Your underground line sounds like a wet return.  But then you saay "traps".  Are you sure you have traps?  Traps are used on 2-pipe systems.

Pics are always helpful.  Take pics of near boiler piping, vents, drips, dry to wet return transitions, and enything else you think would be useful.

Jamie Hall

First thing to do...

If you haven't already, get Dan's books (especially the Lost Art of Steam Heating) -- and read them; there's a lot there!



The boiler cycling seems a bit odd.  You need to correlate this with the thermostat; ideally the boiler should run continuously for quite a while -- over half an hour -- when the thermostat starts calling.  Only after that, when pressure starts to build, should it start cycling -- and even then, a 20 second run is too short.  So see if you can find out a little more about the cycling.



Find the pressure control on the boiler, and take a good photo of it and post it, if you can.



The vents in the apartment with the thermostat may have been turned over to turn those radiators off -- since that's how you turn a radiator off with one pipe steam.  With those radiators on (as you have them now) it may be that that tenant claiming to be cold (tenants are always either too hot or too cold) really is, particularly on relatively mild days, as the thermostat may shut off before much heat gets to her apartment.  This is related to those vents being turned over.



That return line is a wet return, and is quite normal.  No pump is needed, as the water in it stands at the same level as the water in the boiler, or a little higher.  It takes condensate from various "drips" from the steam main -- those vertical lines feeding into it -- and returns it, courtesy of gravity, to the boiler where it belongs.  Dont worry about it unless it leaks...



At a guess, the pressure may be too high -- and you almost certainly need more venting.  Lots more venting.  On the steam mains.  You may also have to fiddle with the vents on the various radiators to get them more even.



More detail...

Abracadabra

edit

meh.. site isn't letting me edit my post.











that first sentence was supposed to be "You need to figure out what is turning off the boiler"

a2shutt

.

Abracadabra-no steam traps. That's what my heating guy thought I had.



Would the cycling be related to the thermostat? It just has a cheapie Honeywell digital programmable. Ok for steam?



I never believe tenants about anything. anything at all. however, I was in her apt the other day and it was COLD. Like she was wearing a winter coat and I didn't blame her. She's told me that she sometimes has to open the windows because it gets too hot, though.



Pressure is at 2 lbs, from what I remember. I'll take a picture of it.



The wet return makes sense. Does it make sense for that to be vented?



What is the best way to add main vents to an existing line? Do I have to drill/tap holes? Where should they be located for max efficiency?



I'm just looking at his books now. That temperature logger looks amazing...it must have to have some sort of transmitter with a stat built in? Not much info on amazon...I'll look into it.

I did read through a bunch of steam info on this site...if you think I have a lot of questions now, you should have talked to me 3 days ago



I'll get a bunch of pics tomorrow.

a2shutt

.

oh-meant to mention that I'm not sure why it is shutting off. There is no reset buttons of any sort tripped, the water level is fine (auto feeder doesn't run). Like I said, I think pressure is at 2 lbs.



I'm thinking its a call for heat issue. But I know nothing

crash2009

Pictures

Most problems begin at the boiler so I guess thats as good a place as any to start with.  Can you post a few pictures of how the boiler is hooked up to the pipes in the ceiling and also how it connects with the pipes in the floor.  Stand back as far as you can and try to get the whole thing in a shot or two.  A couple pictures of the type of radiator you have would come in handy as well.  The A2 in your name suggests we are in the same city in Michigan.  If you need a hand putting together a picture package for the pro's here contact me at 734-604-7007.  I have a pretty good idea of what they need to see.

a2shutt

pictures

Yeah, I'll get pics of everything I can think of.



Haha-nope, I'm 35 min to the west in Jackson, though I'm often in A2 for work. My name and my wife's both begin with A, hence the A2. Thanks for the offer, though, I really appreciate it. Since you're in the area, do you know of a good supplier that will sell parts/pipe/etc to me? I'm not a mechanical contractor.

Abracadabra

...

Depends how the thermostat was wired in to control the boiler.  I've seen thermostats wired so that that start the cycle, but the boiler would shut down on pressure or an aquastat on the furthest return line.  







Need to know what pressure is doing.  Get a good 0-3psi gauge and watch it.  When does boiler shut off and when does it turn back on.  You might to to adjust the cutin and cutout of the pressuretrol.  I'd find out how the system works before you make any wholesale changes.  Set the vents upside down for now till we figure stuff out so that lady on the end unit doesn't freeze :-)

That exetech is a usb temp logger.  You leave it in the apartment for a few days, collect it, stick it in your computer and it'll graph the temp over several days.  You can set it to take temps every 5, 10, 20, etc... minutes. Saves 30000 points. Wet returns don't get vented.  The dry return (end of the main) just before it drops down to the wet return should be vented. Deadmen should have installed vents. I'd follow the main along and see where it goes and before it drops down to the wet return you should have an side-inlet elbow or tee with a spot for a vent.

Pressure is 2lbs.  But is that the cutout? cutin? 2lbs is s bit high  but still should work.  Pressuretrols are not made to control boilers.  They are there to shut it off in the case something goes awry and you need to shut it down. Need model number of the pressuretrol.  Take pics of the dial inside with the cover off.

crash2009

Thermostat

I use internet suppliers mostly.  The locals usually don't have what I want.  http://www.pexsupply.com/   http://www.mcmaster.com/   

Vents upside down in the thermostat apartment suggests that its too hot in there.  Might not be the best place for the Tstat.  Is this room right above the boiler or close to the chimney?

You mentioned the farthest from the boiler apartment being too hot and too cold.  Is it possible that the thermostat is not set properly?  Most of them have an anticipator or CPH setting.  Most of the newer thermostats come pre-set for forced air.  Check the anticipator or CPH setting and set it for steam usually 1.0 for starters. then adjust from there.  These settings can cause short cycling symptoms.



I go to the I94 car auction every couple weeks. 

nicholas bonham-carter

short-cycling problem

use a jumper wire with alligator clips to fool the boiler into running constantly, and see if the short-cycling persists. if the boiler fires continuously, then the problem may be the anticipator, or setup of the thermostat. if not, then the cause could be bad main venting. don't spend any money yet on radiator vents, as they are probably working.

it helps to work on 1 problem at a time, or else it becomes too complicated.

most likely, you will need more main venting , so find them now, and post pictures of them and the boiler&piping. we will help you get everybody comfy.--nbc

a2shutt

update

Ok-here are some pictures. They're from my phone, so if you need better quality of anything let me know.



I ended up cutting the stat wire and hooking the 2 wires together. The boiler fired up like a charm and ran until I unhooked it. I'm guessing this means it's a stat issue? As soon as I hooked it back up to the thermostat it started doing the short cycling again.



The left side of the pressuretrol (there are two of them, by the way...one has a high limit cut off at 5.5 pounds) says "diff" and that's at 5 lbs. THe other side says "main" and that's at 2 lbs.



Also, I looked for main line vents. I could only find one...you'll see a picture of it. There are, however, two on the wet return line. Both of those hiss air like crazy. I hit the side of one of them (since it was blowing some steam out) and the hissing stopped...at that point I heard the main line vent start venting. Could it be possible that the steam is getting dragged down the return line before it gets a chance to get upstairs? The return line seems mighty hot. By the way-do I need to drain the wet return line occasionally to maintain it? Just curious.



I picked up some pipe insulation from a supplier here in town today-it was cheap, like about 90 cents/foot. It's the open-cell foam stuff-does anyone know if this can handle steam pipe temperatures? I've only seen this used on hot water pipes. I've got a pic of it so you can see what I'm talking about.



The one picture below is of the hot water zone plumbing, I forgot to mention that before.

BobC

Closed cell foam NG

One of your main vents seems to be in tough shape, are you sure it's working? How long and what sized pipe is used in your steam mains?



That closed cell foam insulation won't be of much use on steam pipes, you want 1" fiberglass pipe insulation that can be bought at a supply house or online (shipping is expensive so local purchase is best). It's not cheap but it saves money, improves system operation and is a one time expense.



Bob

Abracadabra

LWCO

How often is the LWCO flushed? When was the last time it was serviced?  I'm guessing it might have some buildup inside. Can you post a video of the water level while the boiler is firing?  Near boiler piping looks ok, except I'm not getting that one riser out of the header that's been plugged. Not sure that the one main pulling off the other riser with a tee is ok like that. Seems to make more sense that the main that is fed out of the tee would have originally been fed out of that plugged riser.











Things that make you got hmmmmm...

Pressure gauge.. what pressure does it reach when boiler is shutting off?  Does the gauge even move?  You may need to add a 0-3psi gauge to get any useful data.

crash2009

As Bob said

 that insulation is no good for steam.  There is a place over in Redford named Mechanical Insulation Supply.  Ask for Mike.  He delivers to the U of M in Ann Arbor every week.  His contact info as well as some alternate suppliers can be found here  http://www.heatinghelp.com/forum-thread/137178/Insulation

crash2009

Near boiler piping

Yes, I can agree with that.  Why the plugged riser?  And why not bring the main to the plugged riser.



Is that 2" coming out of the boiler?  Whats the model number?

crash2009

Right side up?

Do I have this turned around the correct way now?  Ceiling looks wet.  Is that an upside down pan, nailed to the ceiling?  Is this an end of main?  Shouldnt this be dropped to the floor and tied in below the water line?  Or maybe not, Is this one counterflow? 

Abracadabra

nice catch!

heh... pan looks likes it's there to catch all of the steam coming out of that vent since it doesn't close up. ;-)

a2shutt

lwco

Not sure on the lwco. I had an issue a week or so ago where the reset button on top of it was tripped, though, and it kept it from firing. When you're talking about flushing it, are you referring to the yellow shut-off on the bottom of the T shaped fitting in the pic with the gauge? The reset button is on that black box to the upper left.



I'll get a video of the water level.



That gauge never moves. I'm assuming it should?



The plugged riser looks like new pipe (replaced when the boiler was, in 07), but I'm not sure why.



That is 2" pipe. I've got a picture of the paper with the model number on it. If it isn't readable I can write it down.

a2shutt

main vent

Yeah, that is the main vent. The only one, unless you count the ones on the return. I could hear it venting today so it must work. That's the one that (I think) only started venting after I smacked the leaking one on the return and made it stop. It was leaking steam so I figured it was stuck open. After it stopped, I could hear that nasty looking vent start to blow air.



The steam mains are 3", then it steps down to some 2" and some 1.5". I don't know on the length...maybe 100 feet?

a2shutt

insulation and vent

I think Ferguson in town here has the fiberglass stuff for $3.50/foot for 2.5" pipe. Is that a decent price, or can the guy in Redford beat that? I'll look him up.



Also-if that t-stat was the problem, how can I fix that? Is there an ideal location (i.e. distance from boiler?) What stat do you recommend?



That is the right side up, and that is the end of the main, although the pipe does a lot of wandering around before it gets to that point. Ceiling was dry, but yeah-that's some sort of steam shield This is the only vent on the main.

crash2009

Diagram needed

You are going to have to measure all the mains, and sketch a diagram.  It doesnt have to be pretty.  Show how many feet of 3", 2" 1.5" etc. Try to show how the mains are currently sloped.  Use arrows on the diagram.  After that we can show you how to figure out how much main vents you need. 

crash2009

You want to

Start with the stat?  Need model number.  Either it has an anticipator or a CPH setting.  Usually we start with a setting of 1.0 

You there now?

crash2009

Maybe

the stat you got is ok.  It might just need an adjustment.  To preserve your sanity you likely need to move it out of a rented apartment, and put a lock box over it, so no one can touch it but you .

a2shutt

stat

The current stat is a cheapie Honeywell programmable, model num RTH221B1000. I've never seen an sort of adjustment on those ones. I'd like to deal with the stat right away to stop the short cycling.



It is currently in a lockbox, but the apartment its in has lots of big windows and I wonder if sunlight, etc mess with it, along with cooking heat, etc. The apartment it is in is about as far from the boiler you can get on the ground level. Only the upstairs units are further away. I'm thinking about moving it to the top landing of the basement stairs...it would be easy to run the wire and it would be in the center of the building.



I looked at that main vent again, and it is at the very end. There are two steam mains-one goes one direction and one goes another. At the very end, they join up and that's where the vent is. I'll make a diagram tomorrow.



Boiler model number is 5IN9LNCLEZ

crash2009

RTH221B1000

Looks like that thermostat is junk.  Don't waste much time with it.  No support at Honeywell.  Cant find a manual on the internet.  Not much here on the wall except for problems without solutions.  Maybe the batteries are just dead.  Change the batteries to get you through the week and order yourself a good one such as Visionpro 8000 with remote sensor.  Install the sensor in the apartment and the thermostat in the hall.  Lot's of support for Visionpro 8000 here on the Wall.



Here is probably the best pipe layout diagram that I have ever seen.  Looking at this one, makes you feel that you are right there looking at the building.  This guy got a quick solution to his venting problem. 



The other pic shows how the steam leaves the boiler, goes to the main vents and radiators, and then returns to the boiler as condensate. 



From looking at your photo's you have some underground returns.  Your underground returns flow back to the boiler.  Looks like the floor was cut to install the returns.  Is it possible that the rusty vent needs this too?



From the looks of the new piping you had someone there that knew what they were doing.  But for some reason they never had a chance to finish.  Budjet cuts?  Do the minimum to sell the building?

a2shutt

thermostat

here's a link to the install manual: http://www.menards.com/main/store/20090519001/items/media/Plumbing/honeywellPlum/Install_Instruct/RTH221Binstall.pdf



Apparently you CAN set the "number of heating cycles per hour"...is that the anticipator setting you referred to? They have a steam setting. Batteries are fine.



I'd be surprised if they never finished. The boiler was installed four years ago and I bought the building 2 weeks ago. I don't think money was much of an object.



Not sure what you mean about the rusty vent.

crash2009

pic 12

That model does not have an anticipator.  You found the setting you are looking for (cycles per hour = CPH)  The CPH is supposed to be set to 1.  It is probably set to 3 or 5.  Set it to 1.



The rusty vent I was referring to is the one that is/was spitting on the ceiling.  The one with the pan nailed to the ceiling.  Your picture #12

a2shutt

...

Ok, I'll change the setting and see how it works. It looks like that remote sensor for the Visionpro 8000 overrides the internal sensor on that stat...I'm not sure that is really what I want here. That would be an awesome way to avoid thermostats in apartments, though.



Yeah, I know which vent you're referring to. I wasn't sure what you were suggesting I do with it. Did you mean that it should be below grade like the return line?

crash2009

Rusty vent

What I mean is that it needs some investigation to determine why it is there.  If it is supposed to be there, how will the condensate drain.  If it's not supposed to be there, why is it there?  etc.  The fact is it is there, and for some reason it's not working correctly.  From the looks of that area it has been that way for a long time.  If you only replace the vent, without correcting the problem, (if it is a problem) you end up with the same thing plus a hundred bucks less in your pocket. 



If you were to remove that rusty vent, and pour water in the hole, where would the water drain to?  Maybe the answer will show up on your diagram.  My thoughts could be way off, but these are the questions that come to my mind.  So if you could, can you get the picture that I described in my previous post?

a2shutt

...

I'll try to get that pic you described, it just might not be possible with the layout of the basement. I think the diagram will answer those questions. I'm just headed out right now to do that.



From what I can tell, the condensate lines just come off the bottom of the steam mains periodically, and run into that wet return which is below grade. The vent is at the very end of where the steam mains (2) meet up.

a2shutt

diagram and photos

Ok-here's a diagram that my structural technologist wife drew. I wasn't able to get into apartments to sketch first/second floor radiator layouts, but the risers going to the radiators are noted at the end of the pipe runs. Crawlspace areas are shaded, and several capped tees and all three vents are noted. I was wrong earlier, the rusty vent only vents one side of the steam main. The side that follows the front of the house appears to have no main line vents. The wet return is shaded in red.



Here's three more photos as well...one is where the wet return ties into the boiler. Another is where the condensate line comes out of the crawlspace and drops below grade...it has one of the vents in the foreground and the rusty vent is not visible, but it is in the background, right above the white plastic lawn chair. The last one is looking down the condensate return...the short boards that are visible are covering up the trench where the pipe runs.



I also flushed the low water cutoff...it was pretty nasty. I flushed about 3 gallons out and it was looking clearer.



I tried to get a video of the water level when the boiler was running but it didn't turn out too well. I've been adding water periodically anyway, since I have a small steam leak that I'm trying to fix. Water level has been staying about in the center of the sight glass.

crash2009

Diagram

Structurely I am sure it's great.  I am unable to see how the steam travels in your diagram.  Can you highlight in red a path from the boiler to all three main vents?  If you were the steam, How would you get from the boiler to the main vent?

a2shutt

updated diagram

Ok, here's a diagram with arrows indicating direction of flow. Note that the ends of the two main runs (in the upper left hand side of the drawing, where the vent is) do NOT join. I think that the only way the main pipe on the bottom of the drawing is venting is through the vents on the wet return...



Red=steam

Blue=condensate

Green=vents

Purple=risers to radiators



Crash, if you're heading west any time soon and you wanted to check this system out, I'd love to have your experienced eyes available...not a problem if you can't, though, I don't want to be a nuisance



I also changed the cph on the thermostat today and it seemed to stop the short cycling...while I was there, at least. I'll keep an eye on it. Thanks for all your help.

crash2009

Close

We are just about close enough to get a professional opinion.  I think we just have to color these red on the diagram.  I cant tell from the picture but it looks like you have the same type of vent arrangement in the background, under the stair.  These carry steam as well, so they need to be red.  They would not turn blue until after the union and under the floor.  Then they would remain blue all the way back to the boiler. 



Glad the thermostat problem has gone away.  What number was it set to before you changed it to 1.  I just re-read the thread.  Jamie nailed it in his second sentence.  NBC nailed the test.  And you did the rest.  Congratulations! 



Some day, I'll drop in after the auction.  Wednesday's after 5

a2shutt

Are you

sure that those carry steam? The reason why I don't think they do is because they come off the bottom of the steam mains...the risers to the radiators always come off the side or top. The purpose of those two pipes seems to be to drain condensate that is running back down the mains.



Also, they pitch back toward the boiler, and there are no radiators being fed off of them. I could be wrong, but I really can't see how steam could travel down them. If nothing else, the pitch would be wrong. That's also why it doesn't make sense to me to have vents on those pipes.



EDIT: Just re-read the conversation and someone mentioned that the dry return section should be vented, but not the wet portion. So-it does make sense to have two vents on the dry part. That leaves me with just one main line vent, though.



If you want, I can take a picture of the junction of the blue and red pipes on my diagram.



Thermostat was set to 5



Feel free to give me a call and drop in whenever. I'm pretty flexible. You can reach me at 517-745-3955.

Long Beach Ed

Here's what I would do...

We're professional engineers and NYC plumbers.  We're also landlords, so your issues are not new to us.  Most of our multi-family buildings are heated with steam.



As  everyone here has been saying, properly venting a one pipe steam system means everything.  It saves you money and balances the system. 



Those main vents are pitiful.  They must be replaced, perhaps even repiped so additional vents can be added.   The radiator vents are also probably in the same shape as the ones on the mains.  Bite the bullet and replace them with properly sized Gorton vents.  They'll last forever and you can adjust the venting rate by switching sizes.



Consider a better thermostat like Honeywell's VisionPro.  Most quality thermostats can be used with Tekmar's remote sensors.  Some even average the reading of two or more sensors.  With some knowledge you can wire several to one thermostat and keep the thermostat in your office or in the basement.



Tekmar makes a line of remote sensors, one of which can be hidden in the wall.  They make another that looks like a blank switch plate. http://tekmarcontrols.com/accessories/084.html?view=product



You should also check the system for leaks, as adding too much fresh water to a steam boiler, particularly the one you have,  will lessen its life considerably.



With some care and some investment, you'll have a good working system.  It seems better piped than most we get to see. 

crash2009

The drip is vented

I thought those were the end of a main, main vents.  So you are saying that the last steam guy that was there, cut into both mains about half way between the boiler and the end of the main.  Then from the cut, sloped a drain, back toward the boiler, and installed a main vent just before the final drop, that runs under the floor. 

I believe you because you are there. 



Are you having any heating complaints from the corner of the building above the rusty vent?  What corner is that N/W?

Do the main vents at the end of the slope/condensate drain get steam hot?

nicholas bonham-carter

Visionpro limitations

It's unfortunately difficult to arrange for the vision pro remote sensors to average the temperature, as they have to be wired "series-parallel", and that introduces the longer (Times 4) length of the thermostat wire into the mix to perhaps throw off the readings. Therefore for averaging, I would choose the tekmar or Honeywell prestige (wireless to boot).--nbc

Long Beach Ed

Tekmar

Nicholas, I'm with you.  I think a seven family building justifies a Tekmar control. 



Check out their steam controller.  Really good stuff that saves us landlords $$$.

a2shutt

...

Yes, exactly. I'm not sure WHEN those returns were installed (they look original?) but that is how they work.



No, the unit above that vent is actually the unit with the thermostat, and it's fine. It's the south-east corner. The rusty vent does seem to work, at least sometimes, but I think it does leak a bit as evidenced by the rust.



The unit I've had the most trouble with is on the second floor, on the north-east corner (the front) of the house. That makes sense looking at the diagram, because the steam main on the north side has no vents. So it's relying on radiator vents, as well as back feeding down the condensate return, to vent. That's my understanding of it.



Those main vents on the return do get extremely hot.