I'm in hot water (pun intended) - Boiler reconditioning

TaylorSquare

first the preface- I'm boiler-stupid. mostly. I'm trying to educate myself as fast as I can, but we have winter approaching and I need help to make a game plan. We have taken over an old 25k square foot school, complete with a steam boiler heating system. the boiler is a 1980-ish Kewanee 7l-280KG, 60HP nameplate rating. it is a three pass wetback firetube boiler operating at 4 PSI. the gas train has been replaced in the 90's. It has been almost entirely neglected during the last 10-15 years of it's life. the last log I can find on water testing was early 2000s.

We've had two tubes with minor leaks pop up, and I've had a machinist build us enough plugs to plug up to 10% of the tubes. Using the plugs with a pillowcase wrapping covered in thread sealant has held up well over the last two months of winter before summer shutdown. We found out the low water cutoff failed years ago and the whole system overheated - the leaks I've found have been within the tubes at the back of the furnace chamber where the tubes are rolled against the boilerplate, so I'm assuming its a combination of heat stress and poor water management. I'm elbow deep now, and trying to come up with a plan to stabilize the thing and see if we can save it - or at the very least, keep it alive a year or two to allow us to set some cash aside each month to cover a retubing.

My current plan is to run a rydlyme recirculation flush through the boiler at or near the 50% ratio. I am debating running a pre-flush of a vinegar solution to loosen up and flush away what loose mud we can. Assuming we may uncover some leaks in the process, follow this with some boiler seal product. Then stabilize the water and begin a proper testing/log/treatment process. The current condensate/feedwater tank is atmospherically vented, and I'm looking at a thermostatically controlled electric hairpin style heater and some insulation to keep the tank stable above 185 degrees to boil out oxygen before chemical treatment.

Apologies for the novel, but I wanted to be thorough about where things sit and what I'm considering doing. I am all ears for anyone who has some advice or information to share!

I was hoping to run what I've put together by you (far more knowledgeable) folks here and get some feedback or suggestions.

Mad Dog_2

 Cool.  I would NOT  put ANYTHING in it. RIGHT NOW.   Does it run now?  Make sure Low Water Cutoffs are working and let it steam...Start flushing when its hot.  If you're not a boiler engineer or very seasoned plumber/boiler guy, I wouldn't recommend this as a DIY project.  How about some pictures too?  Where is the job?  We have top notch Consultants and pros here if so desired. This a SERIOUS piece of equipment...nothing to learn on our dabble...Mad Dog 🐕 

JUGHNE

You would do well to get the book "The Lost Art of Steam Heating-Revisited".

Written by the founder of this web site.

Also, where is this boiler located?

TaylorSquare

Boiler is in Sheridan, Wyoming - and thanks for the recommendation on the book! I'll add it to the list, Dan's videos and papers are what led me to this site and they have been very informative so far. I'll attach some photos.

It does run right now, but is full of mud and sludge - not to mention corrosion. Its in pretty sad shape. We've found and plugged two leaks just last winter, and the low water cutoffs are new. We're of the mind that if the corrosion and leaks are bad enough that stripping the scale and mud out of the boiler turns it into swiss cheese, then it is bad enough already that it will lead to nothing but continual leakage problems. I'd rather invite that demon now, with time to spare before winter, to come up with an emergency heating and then retubing plan over just running it and waiting with crossed fingers hoping it doesn't fail.

I know we are opening pandora's box doing this, but realistically speaking, if it is at that stage, are we wrong in thinking that we're just waiting on unrecoverable failure and leaking problems already? the only alternative I can see is to leave the corrosive mud and buildup, further exacerbating the problem and accelerating the corrosion. I do have contacts within the local VA boiler maintenance section who we can hire for consulting. At this point I am primarily trying to educate myself the best I can on what options we have to try to stabilize it.

Mad Dog_2

Ya gotta let it rip and see how it holds up Kewanees are Tanks. I would Also recommend Ray Wolfarth's Books on Commercial Boilers...absolutely excellent.  I would like to know your experience.  I don't want to see you in over your head, Damage the boiler worse or worse yet, hurt yourself or others.. That is a VERY powerful machine.  You must be very familiar with large  burners, combustion analyzing, plumbing and heating..I wouldn't touch anything until you get a Pro on site.  Keep us posted.  Ray is on the site all the time..hopefully he'll see this.  I have all of his books AND Holohans ..Mad Dog 🐕 

Steamhead

@TaylorSquare , I've been to Sheridan, on my way out to Cody. Shell Canyon was quite an experience.

That's quite a bit of rust. It might be just on the surface, but since you've had some tube leaks, best to get a professional opinion on that boiler's condition. Out there, I'm guessing you might have to look in surrounding states for a steel boiler specialist, and they'd probably charge some travel time, but it would be worth it.

Also, not sure what the laws are in WY, but around here that boiler would have to be inspected every other year. In some states the boiler insurance company handles this, in others the state or local government does.

So tell us about the rest of the system. Is is 1-pipe or 2-pipe? Post some radiator pics, as well as any hardware in the piping around the boiler.

TaylorSquare

@Mad Dog_2 Thanks! I've already ordered the lost art of steam heating and I'll add ray's books to the list as well. I actually have a clipboard for each system in the building as I'm working as a project manager to oversee the construction of apartments within a section of the building. The nature of my involvement means I end up involved in whatever pops up, though. My background is in mechanical and electrical fields. I worked as an electrician for quite some time, as well as methane gas well work, amongst some other trades when I was younger. The owner of the plumbing and heating company that has been keeping this thing cobbled together has been involved as well; he had advocated for maintenance and service for years but the prior owner literally told him he "just wants to keep throwing band-aids at it, and don't send me bills." I do appreciate the aptly due warnings, and all I can say is I'm doing my best to get people involved when I know my knowledge level isn't where it should be - as we go through the stages on this boiler, I'll be most definitely bringing in consultants when it comes time to make any gas train adjustments or anything else outside of my wheelhouse.

@Steamhead Glad to hear you've been through the area! Shell canyon is a pretty drive. the rust you are seeing is due to about four inches of water throughout the fire chamber - the first leak we found and capped. I have no idea how long it was leaking, but the leak is directly at the rolled joint between the pipe and the tubesheet. There was (I think) a heat induced stress crack from the overheating incident at the end of the tube - both of the bottom tubes that sit on the border of the firepath/second pass have been plugged due to cracks at that location. the rust appears to be surface, but we won't really know until I get a scope in through an inspection port to see the waterside. the coating on the inside of the tubes has been bubbled and cooked off from the same incident (again, I'm assuming.) Thankfully, this boiler is oversized for our needs so if we need to reduce the flame due to getting close to the 10% tube cap rate in the shorter term side of things that won't adversely affect us. We're running at about 3.5 PSI so I'm thinking that if I monitor flue temperature to ensure it is staying below the 325-350 temperature range that it'll be an indicator of how hot/close to adjustment time we are running.

TaylorSquare

@Steamhead I missed the last part of your post - to answer, it is a two pipe system. We found that many of the steam traps had failed so we've gone through and replaced all the traps in the heaters. Interestingly, I had 2 - 3/4" F+T 4 bolt Hoffman traps that fed two long-unused forced air unit heaters in the gymnasium- upon getting on a scaffold to check it out, I found original documents for it from 1938! the motor documentation shows it runs bearings made of leather and wool... and requires lubrication weekly. Interesting stuff!

That said, there is no inspections required in wyoming. If there were, we likely wouldn't be where we are today. I'm headed to the bank to go over some plans, but ill get some photos either tonight or tomorrow of the radiators in the building. the piping ill get photos of as soon as I get done with my cleaning/organization of the boiler room.

mattmia2

We'd like to see those instructions.

JUGHNE

I know of 3 Kewanee's about that size and slightly older within 30 miles of me.
2 are in a hospital and being decommissioned. The other is in a 1928 school which sounds like your building to the tee.

I am in your neighboring state of Nebraska, a mere 543 miles from you.
Many on the wall here are in small states and can't wrap their heads around the size of states out here and the distances involved.

Anyway, I just want to comment on the required state inspections we have here.
Every year a steam boiler in a public building has to be opened up for internal inspection by a 3rd party.
The building admin/owners whine about this and the cost of both the inspection, (less than $100) and the service person who opens it up (more than $100) and while there you may as well clean everything.
The boiler must be drained and LWCO floats opened for inspection.
At minimum, at least the boiler is opened up for all to see.

Then later during the heating there is supposed to be an external control test of all safety devices. Most inspectors just walk thru the room to view that the devices are in place. They will usually not touch any controls except on water boilers they will lift the pressure relief valve for about 1/2 of a second. This then will continue to drip as they did not flush it long enough. By the time someone tries to flush it well then the seat is damaged and it must be replaced.

If only that had been a requirement for your boiler.....

Does your boiler design has a clean out plug in each corner of the "mud leg"?

If so then I have opened them up to drain and then with a wand or long hose flush out all the mud possible.
Also some have side and top ports/plugs which will let you wand mud/crud out.

You can then flood the boiler up to the header and look for any new leaks.

I would then lower to standard level, button it all up and fire up steam.

All of these from a cold start will condense and sweat the tubes like pigs.

You would think that you have more leaks but as it heats up they seal/stop.

In any event you do not want it to sit with fresh un-boiled water inside because of oxygen in the fresh water.....but you already know that.

You could drain/flush it again when it cools down.

These things, being steel, are rebuildable somewhat a John Deere tractor.

The hospital has had the entire mud legs rebuilt on at least one of the boilers.

Just a question for any Wallies who might know: Is it possible to simply weld plugs in a leaking tube?? Or a risk of trapped water turning to steam??

Mad Dog_2

Nebraska??? Really?  Ever go to AK-SAR-BEN?  Mad Dog 🐕 

JUGHNE

I tried to find it a few times but no luck....but then I suffer from dyslexia.

Mad Dog_2

It closed in late 1990s I believe but was a very popular Thorougbred Racetrack that drew fans from surrounding states. One of my Grandfather's Charges, 1935 Triple Crown Winner Omaha was retired out there and is buried there with a Monument. Mad Dog 🐕 

JUGHNE

All gone now, replaced by condos etc.

retiredguy

If I were you, I would contact a good commercial boiler company in your area and have them do a complete inspection of the boiler both the internal and external. If you have any hospitals, universities, schools etc near you I would ask them " who they get to do their boiler work". Call that company and explain your situation and ask for their help. Looking at the pictures you posted does not tell the whole story. If you have leaking boiler tubes that boiler may need to be completely re-tubed. The plugging of boiler tubes is only a "temporary fix" . If that boiler overheated or dry fired it needs to be inspected both inside and out to make sure it is safe. Remember that all these pressure vessels can hurt you and in the event of a catastrophic event can cause a lot of destruction.

Mad Dog_2

I think The Omaha Statue still stands .  Mad Dog 🐕