Boiler Tube Plug Installation advise.

MGREGORETTI

What is the correct way to install a tapered, cast iron Boiler tube plug on a steam boiler. The Boiler is 1,000,000 BTU gas fired Columbia, steel fire tube design with 2'' tubes . the boiler is used for process steam at 13PSI. I have been in the business for a long time BUT never installed a tube plug. Who says just smash it in, Who says wrap it with a rag, Who says use thread sealant ???? but what is the right way??? Any help would be appreciated
( I have been unsuccessful on 2 occasions and the customer is starting to look at me Funny)
Thank you
Mike

ScottSecor

It has been years since I plugged a tube, but here goes:
Turn the boiler off and let it cool a little, I would guess about 140 or less, ideally room temperature. Wrap a layer of cotton gauze or a cotton rag around the cylindrical part of the tube plug. Tap the wrapped plug into the tube, as far as you can get it. Ideally, only about one third of the tube will stick out. I suspect you know this, but you must plug both ends of the tube this way.

I've also used expanding cement a few times with limited success. Finally, for very temporary repairs I have seen wooden plugs used.

EdTheHeaterMan

I had a customer with a steam boiler that owned his own tube replacing tool. It forms a bulge in the fire tube that will hold quite a bit of pressure. I replaced some tubes 2 times during the heating season for them. It went fairly quick. Is tube replacement not an option?

ScottSecor

"Rolling tubes" is somewhat of an art. Not a lot of companies that still do that type of work here in NJ.

EBEBRATT-Ed

Still a lot of fire tube boiler being built. @ScottSecor , I have herd of wooden plugs as well. A school I worked in in Vermont, the custodian was an old timer who was pretty savvy. He came in one morning and the boiler was leaking. This was a good-sized middle school with only one boiler.

He told me he measured the tube and went down to the wood shop (back when schools had shops) and found some hardwood and turned some plugs. "They will swell up when they get wet" he told me.

Mad Dog_2

Scott.. I bet your Dad (Ken) showed you that,  right?  He had done it all.   One of my greatest Foreman who broke me in, Jimmy O' Brien was straight out of Dublin.  He entered His Plumbing Apprentice at age 12.  They went to live with The Licensed Master & his family. They learned everything including basic electrical and carpentry.  He loved his little wooden dowels and had an old tool box with dozens of hand-whittled ones of all sizes.  I forget the type of wood, but it wasn't pine.  It was like Locust or poplar or walnut.  Mad Dog 🐕 

MGREGORETTI

Thank you for the reply
I tried wooden plugs - they seemed perfect - made a nice seal and were easy to install BUT they burned up after about a month
I will try the gauze next - Do you put any thread sealant , High Temp silicone or anything else with the Gauze or do it Dry?
and keep you posted
Expanding Cement sounds interesting also
Thank you MG

ScottSecor

I assumed this was a temporary repair, did not realize tube was leaking for a month or more.

I have not used sealant/caulk, but I suppose it could help. To be honest, the repairs we did were on low pressure (heating) boilers during the heating season. As a result, we did not have the time to wait for some high temperature sealant to set up. Always had to get the heat going asap. Just used dry gauze, about 1/8" thick.

Something like this is what I've used. https://www.homedepot.com/p/DRYLOK-4-lb-Fast-Plug-Hydraulic-Cement-Mix-00917/100553093?source=shoppingads&locale=en-US&&mtc=SHOPPING-BF-CDP-GGL-D24-024_012_WATERPROOFER-NA-Multi-NA-SMART-NA-NA-NA-NA-NBR-NA-NA-NA-FY21_Exterior_SMART&cm_mmc=SHOPPING-BF-CDP-GGL-D24-024_012_WATERPROOFER-NA-Multi-NA-SMART-NA-NA-NA-NA-NBR-NA-NA-NA-FY21_Exterior_SMART-71700000081717307-58700006942061315-92700062508088588&gclid=Cj0KCQjwnMWkBhDLARIsAHBOftqQA2GCln5TllwSZf7vvbxS9xZU3j2evjYMrKpn1IxoY4Kzpu4frkQaAolwEALw_wcB&gclsrc=aw.ds
Clean the surface of the tube. Use an entire piece of newspaper, roll it into a ball and stuff it into the tube about four inches. Then make the cement mix and fill the end of the tube, pack it tightly. Repeat on other end of tube. Ideally the cement forms a solid plug of cement and prevents any water or steam from escaping. I would say about half the time we did this it actually worked well enough to get by.

Finally, if memory serves I have never plugged a steam boiler that operated at more than two or three PSI. I have plugged a few water boilers that operated at 12-20PSI.

ScottSecor

My suggestion is to have the boiler tubes replaced. If money is tight just do the ones that failed and the ones that look bad. If funds allow, replace all of them asap. In my experience, if more than one fails they are all compromised and will fail soon.

What area are you in?

retiredguy

I can recommend this company since I worked for them for about 34 years before retiring. They are CS&E; in Pittsburgh, Pa. call 412-821-8900 and in Philadelphia, Pa call 484-873-3974. They can take care of all your boiler needs, large and small.

Plugging a boiler tube is only for a quick and temporary emergency fix.

MGREGORETTI

THANKS BOYS!
will keep you in the loop
MG

tim smith

here is a company that stocks them. https://oswaldsupply.com/products/2-drive-in-boiler-cast-iron-tube-plug?variant=34508925960329&kw=MTP2C&c=Shopping&utm_source=google&utm_medium=cpc&utm_campaign=PMaxSmart-shopping&kw=&ad=&matchtype=&adposition=&c=PMaxSmart-Shopping&gclid=EAIaIQobChMI8KyXs5XX_wIVNAGtBh3r7wwlEAQYAyABEgIWJvD_BwE

tim smith

I agree on the replace tubes much better option.

tim smith

Check with boiler inspector 1st I feel. If he says no way then I follow inspectors decision.

jerryb46

Used a cotton rag wraped around tapered cast iron plug smeared with good old black PERMATEX the stuff that stickes on you hands,or HERCULES GRIP,good luck

dopey27177

The best way to plug the boiler tube is to use a cast iron or steel tapered plug.
The cast iron plug will need to have cotton wrapped around the plug. The steel tube if tapered properly needs nothing. A two pound hammer or 3lb. hammer is needed to set the plugs.
Jake

KC_Jones

ScottSecor said:

I've also used expanding cement a few times with limited success. Finally, for very temporary repairs I have seen wooden plugs used.

My grandfather did this as an engineer on a Liberty ship during WWII. This was while they were in the Mediterranean Sea with no help close by, no machine shop on board, but they did have a wood shop. Plugged it and finished the voyage that way. His boilers were oil fired water tube. The plugged leaked briefly until the water swelled it up and it sealed tight. Those boilers run over 200 psi.

Fun side note, he had spare tubes, but didn't have the tools to replace them. He was in the process of trying to do it manually using a cold chisel and hammer to get the leaking tubes out. A foreign (friendly) ship came close to offer help, they showed him the wood plugs they used and gave him a couple. Well, they were metric and didn't fit right, so he had the wood shop make him some that would fit. He was desperate as both boilers were leaking and on those ships, everything is run off the steam so it was an emergency.

MGREGORETTI

DEAR HEATING HELP GANG

I would like to thank you for your input regarding the installation of tube plugs. Here are the results of my experience with them.

1. Wooden tube plugs ( Oswald Supply) are effective for short term results. They actually burn up after a few weeks installed.
2. Wrapping a cast iron tube plug ( OSWALD SUPPLY) with a rag and then jamming it into the end of the tube is ineffective long term. It was my experience that the ragged burnt and the tube plug began to leak after only a few weeks.
3. Coating the tube plug with Teflon pipe dope and jamming it into place also proved to be ineffective in the long run. The tube plug lasted only a few weeks and then began to leak.

At this juncture, the thing that appears to be working is installation of the tube plugs with a substantial amount of high temperature silicone, jamming the plug in place with the assistance if a 3lb lump hammer. THEN allowing the silicone to cure overnight before operating the boiler.

We then added liquid boiler sealer as a backup and to prevent any small leaks from appearing in additional tubes. I used PUREPRO liquid sealer 41-135

We then chemically treated the water for PH & added oxygen scavenger.

It is more than 3 weeks and all seems good- we are running process steam at 13 PSI

Thanks to all for participating in this discussion
Enjoy the Summer!
Mike G.

ScottSecor

Mike, thanks for sharing your experience. I think I learned something that I may use in the future.

The only real "catch" for me is most times there is a single boiler on site and the tube fails in the middle of winter. That means we need to get the system up asap and rarely have time to let high temperature silicone set up (especially on a hot, extremely damp boiler).