Purchased a former school with steam / pneumatic heating - HELP!

Tom_H

Hi everyone, I have been doing all sorts of research and checking out many of the threads on this site which has some great information. Here is my situation - I will try to keep it fairly brief. I will continue to add questions as I progress with this sytem...

I have just closed on the purchase of a former elementary school. Its one level, approx. 23000 sq ft. It has 2 large boilers for heat and is a 2 pipe steam system. Thermostats / actuators are all pneumatic. The school has been maintained, but not in service for the last 7 years. Heat was maintained with sensors which turned the boiler(s) on at 55 deg. and off at 58

Siemens has installed some controls for day/night mode and a few other things which is for a separate thread.

I have already found and fixed a couple of air leaks, but the air compressor in the basement runs about every 13 mins for a few mins at a time. Correct me if I am wrong, but this seems like a lot. Compressor kicks on at 45psi, off at 70psi. Then the pressure is reduced to 25psi or 8psi, depending on if the system is in day/night mode.

My main concern right now is maintenance. I have not counted the steam traps, but I would guess there are approx 50. Mostly F&T and Thermostatic i believe. Also many strainers and controls for HVAC which I am assuming is due to the fresh air intake that is required for public schools. When I turn the boilers to "day" mode, steam pressure is maintained. Boilers kick on at 3psi and off at 7psi, which seems to be high based on what I have been reading. However, I have had trouble finding much info on commercial systems. I have not messed with pressuretrols or anything since I am scared that I will screw other parts of the system up.

Anyway - main issue is that I am blowing a decent amount of steam from the return condensate tank air vent. I am guessing this is from failed steam traps. I have done a ton of research on trying to find failed traps with no success. I have a thermal imaging camera and also purchased an ultrasonic tester. Both of these methods have not helped me to find a trap that is definitely failed. The traps we have opened up seem to be pretty clean (which i know does not tell us that it's not failed, but I thought for sure the system would be full of all sorts of sludge, rust, etc.) I have also opened up some of the strainers and they also look decent, just some rusty water that comes out.... The largest steam trap I found has a tag that reads "warren webster size 26-T drip trap". It is at the end of one of the steam supply runs and looks older than dirt. Since its in one of the large crawl spaces in the school, I am guessing it has not been maintained. Could a trap like that that is failed produce a good amount of steam? I am scared to open it up since I don't have any (and cant find any) parts for it. Not to mention I am scared to break it since it's pretty rusty. I have attached a photo.

I guess to sum this up, if you purchased a fairly large building with a steam system, what are the first things you would do / check for maintenance?

Any help is appreciated! Thanks in advance
Tom

Dave in QCA

Congratulations on your purchase. It is always a great thing to find a good pneumatic system that is working condition. They are excellent at controlling space temperatures accurately and operating the fresh air, etc. They are simple in operation, although mysterious to many who don't understand them and are quick to ripping them out. Don't do that!

The compressor run time does not sound excessive to me, but it all depends on how many thermostats and controllers you have in the system. Every thermostat, even if it is in a static condition continuously bleeds a very small amount of air from it. By the way, what type of system is it? Johnson, Honeywell, Powers, Barber Colman? All run about the same, but have their own quirks.

The steam trap leak by that you are having should be able to be traced. The condensate lines should NOT be hot as steam. I would think if you started tracing with your thermal camera when the steam was blowing through the condensate tank, and started tracing back along the line, you will find the culprit. It might very well be that last trap. I think I saw something within that last few days showing someone at Barnes and Jones testing a trap like that.

OH. And by the way, most of the guys on here are accustomed to residential steam. You're probably going to hear advice to turn down the pressure because residential is supposed to run at no more than 2 psi. But, you have a system that has pressure maintained continuously and control is via the pneumatic control valves. Institutional systems such as yours typically run from 5-10 psi. Your are on the low side at 3-7. You can probably get by with running only one boiler in mild weather, of course.

Jamie Hall

I am by no means an expert on large systems like yours, but I do have a few thoughts and no doubt the real experts will chime in.

First place, at those pressures -- which may well be too high, but one needs to check as some things need more pressure -- some of the steam you are seeing may be from the condensate flashing into steam as it was at higher pressure -- and hence could be above atmospheric boiling.

It could well be from failed traps, too. The only really reliable way that I know of to find a failed trap is to measure the difference in temperature between the inlet and outlet. It helps to wrap electrical tape around both pipes, to get a uniformly emitting surface. Use an IR thermometer. The inlet can be as high as your steam temperature (something above 212). The outlet should be at least a few -- say 5 to 10 -- degrees cooler. If they are about the same, then it is very likely that steam is bypassing. On the other hand, if the outlet is much cooler or even room temperature, then you may have a failed closed situation.

Dave in QCA

Jamie makes some very good points. However, keep in mind that the pneumatic controls will modulate the control valves and in the case of convectors and particularly classroom Univents, when space temperature is not coming out of a setback, the control valves will be only partially open, heating only a portion of the coil, and in this case, the condensate will be quite cool.

ratio

Whoo, boy! First, congratulations! I maintain two former schools, and the maintenance is never ending and expen$ive as you-know-what.

How old is the bldg? After 60 years, I'm starting to lose underground condensate lines--had to add a chem system to try and save what's left of them. Pay a lot of attention to any underground condensate lines, they're the most expensive part to repair.

It's almost certain that there are some traps blowing past. My bldg hadn't been maintained in years, I have a significant number of original traps still in ...well, I can't call it in service, but they're still in there. I've been giving some thought to installing inlet orifice plates to alleviate that, read more here and here.

without knowing your system it's hard to say whether the steam pressure is too high, but I've been inching mine down, from 5# when I walked on the job to 2# currently, and I'm intending to go as low as I can. If you're nearby the site it's nothing to crank it down, it can be turned up in a few seconds once you're on-site.

Post some pics of the near-boiler piping. You'll get a free consult from some of the most knowledgeable steam people in the country.

Where are you located?

Tom_H

Thanks so much for the replies Dave / Jamie. I will try to answer the questions from you guys as I recieve them:

I am guessing, but I believe there are about 18 thermostats in the building. As far as type of the system, I am not sure. There are all sorts of electro-pneumatic valves that say powers on them. Some other valves say Siemens. I will take some pictures of the compressor, t'stats and attached stuff tomorrow so you can get an idea of what I am working with.....

On the traps i have tested, I get temps going into the traps around 210 and up. The other end of the traps read about 7-10 degrees cooler. If that is acceptable, I will continue to test this way and hope to find a trap that has the same temp on both sides and start there. I have not found anything to make me think of a failed closed trap. All areas that are supposed to heat get very hot.


The mention of running only one boiler brings up another issue. Right now, both boilers work, but only one boiler will run at a time. They are hooked up to a "lead/lag" switch. I can move the switch to tell boiler # 1 or 2 to run, but they will not run together. I don't even know where to start with that issue. Again, I will take some photos of the boilers / switch tomorrow and post them.

I am not 100% convinced that the air is as "dry and oil free" as it can be. We just installed a new air dryer since the old one was looking pretty bad. It seems to be operating but I am not sure exactly how to make sure the air is acceptable.

Keep the comments coming!
Thanks,
Tom

Jamie Hall

Tom_H said:

On the traps i have tested, I get temps going into the traps around 210 and up. The other end of the traps read about 7-10 degrees cooler. If that is acceptable, I will continue to test this way and hope to find a trap that has the same temp on both sides and start there. I have not found anything to make me think of a failed closed trap. All areas that are supposed to heat get very hot.


The mention of running only one boiler brings up another issue. Right now, both boilers work, but only one boiler will run at a time. They are hooked up to a "lead/lag" switch. I can move the switch to tell boiler # 1 or 2 to run, but they will not run together. I don't even know where to start with that issue. Again, I will take some photos of the boilers / switch tomorrow and post them.

Sounds like so far, so good on the traps. On the two boilers -- if the pressure is adequate, you may not get both boilers to operate -- if there's enough pressure with just one going, there's no point to running the other one! It may be that the lag boiler will only fire up on really cold days, when all your thermostats are calling for heat.

At least, that's the way it's supposed to work...

Tom_H

Thanks ratio - I will read the links you posted and certainly post a bunch of pics tomorrow or Monday to show what I am up against. So far, I do not have any issues with overheating since the pneumatic thermostats and actuators seem to be functioning correctly for the most part.

@Jamie Hall - I would agree with your idea of one boiler running unless the other is "needed", but the way the "night mode" works, the boilers kick on at 55 degrees and off at 58 degrees based on a sensor in the center of the school. This means that upon startup, there is 0 steam pressure. At that point, I would think that both boilers would kick on. I would assume that one of them would shut off at a certain pressure, say 3 psi and the other would run to get to the 7psi. Then, it would be maintained with one boiler until the pressure dropped below 3psi and there was a "demand" for heat.
I would assume that "demand" for heat at 0psi steam pressure would tell both boilers to fire.

I am wondering if the pressuretrols are not working correctly. There are 4 pressuretrols for each boiler. I am assuming it's 2 for the boilers and 2 for the "lead/lag" system. Both boilers have pressure gauges and they read the same so I am assuming I don't have any blockages in the pigtails but one of the units themselves could be stuck. Anyone know how to test them?

Thanks to everyone for the help - Tom

JUGHNE

Often the boiler is just maintaining pressure waiting for some valve to open. Manual shut off in spring.

At what point in higher operating pressure do the pressure rating of F&T get bumped up from the 15 to 30 rating.

His picture showed a 15 PSI rated "drip trap" (I assume F&T)?

Dave, what do you think the limiting factor for a building like this would be as far as lowering the pressure? Pipe size or EDR.?

Dave in QCA

Limiting factors on lowering steam pressure
I believe there is more than one issue to contend with, but they all have to do with the parameters under which the entire system was engineered. If the system was designed for 5 PSI, then the Cv factor of the control valves would have been selected to enable effective control through the control range of the valve, with full open being adequate to fully heat the coil according to its effective EDR. Keep in mind that there may be some coils that are in classroom Univents or air handlers that may have a mix of outdoor air, or even 100% outdoor air. Adequate supply of steam through the control valve is critical to avoid coil freezing in very cold conditions. Also, it is common to find conditions where the condensate return line is located above the outlet of a coil trap or drip trap. This is never a good practice, but I have seen it pretty often, and it requires that pressure be maintained sufficient to provide the lift.

Keep in mind that the boiler will operate or cycle as necessary to maintain pressure in the mains. If the boiler shuts off at 7 psi, the boiler will continue to boil slowly as the pressure drops. The temperature of the boiler will be hotter at a 7 psi pressure and as steam is used, the boiler will continue to generate steam, even with no fire, and as this happens the boiler temperature will fall. Steam will be used at any point where a control valve is allowing steam into the coil, and of course, due to the heat loss of the piping. That piping loss generally winds up in the building, so whenever the outdoor conditions warm up to where heat is not required, shutting the boiler down and allowing the piping to cool will produce measurable savings.

JUGHNE

Dave, not to hijack the thread, it is somewhat the same issue but, I'm possibly going to work on a 1938 2 pipe schoolhouse. The pressure was set at 6 PSI. There are 2 3" mains with zone valves leaving the boiler room and only feed CI rad and 2 hanging heaters. No lift of condensate is needed and not outside air to coils. I have already set pressure down to 5 PSI. Many issues with this system and I believe the "remedy" was to jack up pressure. So if my proposals are accepted I will slowly set the pressure down as repairs are made.

Now the OP project, I have a 1961 school with powers pneumatics running hot water. Use of the building is very limited, one classroom 5 days for pre-school. Rest of building one evening a week. Lots of outside air dampers thru Neisbet fan coil units. Because there was a lot of fresh air from leaking envelope of building, I disabled all air dampers and sealed inlets with 1" foam insulation. The building is set on "Night" air pressure permanently. The single room teacher knows how to set her own T-stat to "Day" to raise temp if needed. Day will activate the fan and its coil valve. BB heat is always on to keep most rooms at 55-60. The daily use room has only 1 outside wall and the BB flow is jacked up to keep it warmer. For the Wednesday evening class the teacher will go to the boiler room and switch the entire building to "Day" air pressure.

This system needed a lot of attention; just to sum it up--when enough water leaks out of the 1/4" air line at an air/electric switch to short out the switch then you know there was some neglect, mostly didn't know what they didn't know. But you have to love volunteer help, don't you.

I have had the original brass/steel Powers Day/Night T-stats rebuilt. Some money involved, but to retain the features of Day over ride lever on each T-stat and concealed set point dials outweighed the costs. IMO----plus I don't like plastic.

Tom_H

I believe that all fresh air functions in my school have been disabled. The dampers on the air handlers that bring in cold air have been disconnected, and the classrooms that have the Trane classroom heaters have the outside vents blocked off. The school did this after shut down to save money and not bring in cold outside air if it wasn't necessary.

I think I need to test the 8 pressuretrols / vaporstats to see if they are working, but not sure how. While I am doing this, I could lower the steam pressure to 4 or 5 while I am there and see how it affects everything. I can also go around and make sure things are still heating.

I really need to figure out why only 1 boiler is operating at a time. I know the building will heat with one boiler, but I also know it's not working correctly which bugs me.

@ratio The building was built in the early 50's, one wing is an addition that was put on in the late 50's. I am located in northeastern NY near Canada / Vermont (Way upstate )

Dave in QCA

@Tom_H Regarding the reasons that your lag boiler is not operating. I can think of a few reasons. During this time that the building was out of service it makes sense that they would NOT have wanted the lag boiler to operate. So, perhaps, is wired so that it will not run when in the Night Mode as you have described. Or.... Given that in a lead/lag mode, there must be 2 pressurestats, one with a lower setting for the lag boiler. Perhaps, someone has adjusted the lag controller all the way down so that it won't run, or perhaps, a wire has been pulled from a terminal. You're going to have fun finding the cause. Any blue prints? Control drawings?

Tom_H

@Dave in QCA No blue prints / drawings so far. There is some paperwork that I have gone through quickly, maybe I missed some stuff in there.

Regarding the possible adjustment: I know this is not the case. I am friends with a former custodian from the school. When it started to get cold out, I met him at the school so he could show me how to fire the boilers up. When we did that, both boilers were firing. I have to assume that a switch is failing - and like you say....not going to be much fun chasing wires.

Tom_H

Another thought: Do they make special tools for opening up strainers / traps? I have had a hell of a time removing some of the trap caps and opening "Y" strainers with standard pipe wrench or adjustable wrench. If so, where can I find them? If not, is there a trick?

ratio

Far from me, I'm in central Ohio. Your situation sound similar to mine, although your system is probably bigger. I've got one Peerless, about 44 HP. Two additions, one steam & one hot water, to about double the original square footage.

I had some thaw-outs last year in the wet wing when the boiler flooded & the vaporstat saw 32 oz in & decided not to being the burner back on.

nicholas bonham-carter

There is a lot to be said for having a system with radiators and TRV's, instead of all the complezity in your system.
Of course even radiators can be knuckleheaded.--NBC

JUGHNE

Tools: I have had good luck with 18V 1/2" impact wrench. Still use back wrench though. Need 6 point socket for hex and 4/8 point for square plugs. Impact rated sockets are a good idea however Sears will replace Craftsman cracked/broken sockets free. These have worked really well for rad trap lids and the guts also. Again the back up wrench and a well fitting socket.

(friendly mechanics will loan me the bigger impact sockets)

If the wye strainer plug has pipe threads I put in a nipple and cap or ball valve for blow down. Easier to unscrew in the future.

Tom_H

I took some photos today. I will post them over a couple posts since they are good size photos

Tom_H

More photos...

Tom_H

And more photos

SWEI

I'm curious -- what are you planning to do with the place?

Dennis1679

I would suspect the 26 T. It looks like it's never been touched!

JUGHNE

There is a video/discussion about WW 26 T farther down the page of the wall. Page 2 if you are looking at The Main Wall.

neilc

Tom_H said:

The building was built in the early 50's, one wing is an addition that was put on in the late 50's. I am located in northeastern NY near Canada / Vermont (Way upstate )

This isn't Wilsboro NY , is it ?

neilc

Nope,
nevermind,
not with gas, I don't think so anyways,

Sailah

I've tested my fair share of traps with a FLIR camera. It can very very easy to be fooled by a bad trap that is masking others. So if you have a bad trap it can back flow in the condensate line and give high outlet temp readings to other traps that are good, but are reading high on the outlet. In this case an ultrasonic tester is used to hear the trap.

I'm typically looking for a larger differential than 7-10 degrees. It all depends on pressure. Last week I was at an industrial plant with one of our new distributors. They were running 125psi. At a modine heater I was reading 300 degrees inlet, outlet at 190. Lower pressures I see 210 inlet, 180ish outlet. Rarely do I see them 7-10 degrees apart.

If you look at a FT trap from the side with a FLIR, you should be able to literally see the water inside by the color gradient. The yellow should be at the top and the bottom should be orange. If you see all yellow, the trap is blowing because the cast iron is all the same temp.

We do have parts for the old warren Websters, but won't have float mechanisms. We have the air vents for both the bolt on covers and the screw covers. I did a video testing them for Gordo a few months ago.

Tom_H

@neilc Not willsboro, but close
@SWEI I am moving my existing restoration business into it and also have a tenant that will be renting about a third of the building. Works out great since the tenant is in the educational field
@Dennis1679 I agree. I will be checking this trap tomorrow with the system running. Certainly has no evidence of it ever being rebuild. It's at the very end of one of the crawl spaces. About 100 feet in and not a great environment with pipes, etc.

Tom_H

@Sailah Is there a gasket that will need to be replaced with that trap or can I just try to tear it apart and at least see if the float is good?

Tom_H

@Sailah - I have some replacement kits that i found in the school. They are: Watts 3/4 WFTC -15 SKU 0038100

Do you have the equivalent of these kits? If so can I get pricing?
I have not found any bad floats, but need the gaskets for sure and maybe the thermostatic element in them. Is there a way to test the element?

Sailah

Tom_H said:

@Sailah Is there a gasket that will need to be replaced with that trap or can I just try to tear it apart and at least see if the float is good?

I can't remember if there was a heat gasket, guessing there was. But almost any gasket material can be used, just trace and cut. I would procure the gasket material first then open the trap.

Tom_H said:

@Sailah - I have some replacement kits that i found in the school. They are: Watts 3/4 WFTC -15 SKU 0038100

Do you have the equivalent of these kits? If so can I get pricing?
I have not found any bad floats, but need the gaskets for sure and maybe the thermostatic element in them. Is there a way to test the element?

Our FT-15 head is a direct replacement for that body in addition to practically every other 6 bolt FT trap made other than some Hoffmans. If you just need the elements and gaskets that's for sure cheaper than buying faceplate kits. It uses a 159 cage unit and a 1330-196 gasket if I remember correctly. If you want to call me tomorrow we can discuss.

Regarding elements being tested, yes you can hook up a trap and test to atmosphere. That should tell you if the element is good or not. You would put in a 3/4" pipe plug in one outlet, a elbow in the other and aimed into a bucket. Put the steam on and you should see it seal up quickly. If you are getting lots of blowby the element is bad. Or send it to me and I can test it.

Tom_H

@Sailah PM me your number, I can give you a call tomorrow.
Thanks,

Dennis1679

I believe Tunstall makes a rebuild kit for that trap. Most of the other traps I've rebuilt with Barnes and Jones