Should we even try to replace the pipe?

eakers

Hi, our very old boiler has a leaky pipe. It’s the one that goes from the regular house plumbing into the housing of the boiler. The repair guy said it will likely crumble if he tries to take it off, and that it’s even possible that the boiler itself will crack as he’s trying to get the old pipe undone. The alternative is a whole new boiler that is 300K btu with a pretty hefty price tag and will take five guys a super-long day to do. I know nothing about boilers so I don’t know what our options are. The house is 114 years old and we have 11 radiators on two floors and one in the attic that is usually off. Any thoughts on our options? Evidently our current boiler is only about 60% efficient and the new one would be about 84, so our gas bill should go down. Truth be told, I kind of want to wrap some flex tape around that pipe joint and see if we can make it through the winter. I’d be grateful for any advice. Thanks!

WMno57

eakers said:

Evidently our current boiler is only about 60% efficient and the new one would be about 84, so our gas bill should go down.

Did the company trying to sell you the new boiler tell you this? Probably more like 5% more efficient.

eakers said:

The alternative is a whole new boiler that is 300K btu with a pretty hefty price tag

Steam boilers are sized to the EDR of the existing radiators. That is the only way to size a replacement boiler. Did they measure your existing 11 radiators. 300K sounds oversized.
You need to get another professional opinion.
Please try the Find a Contractor Tool here:
https://heatinghelp.com/find-a-contractor/

ScottSecor

You are dealing with the devil, no easy answer. Not sure why the piping ties into both side of the boiler, but that is not the issue at hand.

We have done this exact job many times.

About 75% of the time we were successful and the boiler at least made it through the heating season.

About 15% of the time the piping was rotted much more than we anticipated and we had to replace a much larger section of pipe (adding cost to the already expensive repair).

Finally, about 10% of the time the cast iron section failed at or near the threads. This resulted in a new right end boiler section (not so available these days) or a new boiler.

pecmsg

I'd try replacing it.

WARNING.
Do Not Attempt it this time of year!

ScottSecor

Search this website for a few minutes with regard to sizing steam boilers. DO NOT go with the contractor that simply wants to replace the boiler with the same size. It is critical to size the boiler properly. By doing so, you might save some money upfront, save some money on your utility bills and save some money on repairs as the boiler will cycle less often. More often than not, existing boilers are oversized, sometimes significantly.

Finally, your piping setup is less than ideal. I understand you are likely not a steam expert like so many on this site. But take a look at the Weil McLain EG or EGH manual for what the piping should look like. Yours, does not appear to follow the drawings. Please post a photo of your near boiler piping, including the supply piping (comes off the top of the boiler).

Jamie Hall

I'm not totally convinced it's the pipe or the elbow... it may be the threads into the boiler. Not very promising, in any case.

ChrisJ

That boiler is likely 80-82% efficient unless there's something really wrong with it like a lot of mineral build up.  A new atmospheric boiler will run about the same. 82%ish.

Unless they're installing a wet base oil boiler with a gas gun installed in it.   In that case you could see an increase in efficiency.

ChrisJ

pecmsg said:

I'd try replacing it. WARNING. Do Not Attempt it this time of year!

I'm thinking that boiler falls into this category even though it's not a bolt.

EBEBRATT-Ed

Chances are the boiler is ok and will just need the rust flushed out of it. The steel nipple rots before the cast iron. When you get a nipple like that that leaks it is probably full of mud.

If you want to try flex tape go ahead. Do not let that plumber put in the new boiler he doesn't know what he is doing.

Patch the leak, start saving for a new boiler. Measure all your radiators to size the new boiler and then the most difficult part search for a steam contractor that knows something.

Post your location and check 'find a contractor" on this site someone may have a recommendation.

KC_Jones

Based solely on what you posted, do not hire that company to do anything. As stated above, no way you need a boiler that big, unless all your radiators are the size of the titanic. Also, a real professional probably wouldn’t shy away from that pipe change, unless eyes on the ground saw something we aren’t seeing in these pictures. That’s a fairly typical rotted out pipe to my eye.

Trying some flex seal has basically zero downside, if it works, great, if it doesn’t you haven’t lost much.

I’d probably try a patch for winter with a plan to repair after winter.

BobC

Make a list of all your radiators with columns for height, thickness, length and number of columns or tubes in each section, and the number od sections in that radiator. Take pictures of a representative radiator, take separate pics of any different style radiators. You can then sit down with a boiler sizing table that shows and lists the different kinds of radiators and tells you what the EDR for each section is.

Add all those EDR's up for each radiator and in 1/2 gour you will know if he's blowing smoke up tour ****.

Bob

EdTheHeaterMan

Steam boiler sizing starts on page 9 https://www.weil-mclain.com/sites/default/files/field-file/Weil-McLain_BoilerReplacementGuide_WM2012-web_0.pdf

EdTheHeaterMan

Also. Regarding the existing boiler efficiency. Your boiler is equipped with an automatic vent damper. That is almost identical to what the replacement boiler’s efficiency will be.

I believe the technician’s diagnosis and information is less than accurate. No savings will be achieved wit a boiler replacement that the same size as the existing boiler.

There may be a small savings with proper sizing and piping.

Hap_Hazzard

I replaced this pipe on my boiler. It wasn't a piece of cake, but I did it. I don't know what your skill or experience level is, but it involves some decent mechanical skills. These pipes almost always rust through where the threads are, because that's where the walls are thinnest, so if you grab the pipe with a plumbers wrench and try to turn it, the pipe will collapse. That's okay though. You need to persuade it to keep collapsing as the threads go into the boiler, so you're basically peeling the pipe away from the threads in the boiler casting.

You usually can't get all of the pipe threads out of the casting, so the object is to expose enough of the threads so you can run a 2" NPT tap into the fitting and clean it out. If @Jamie Hall is right, and the threads are damaged, you can usually tap the threads bigger by running the tap deeper into the casting. The casting is thick enough to allow this, and then you can just thread the new pipe in until it seats. This is the beauty of tapered threads. I don't think the boiler threads are damaged, but I could be wrong, and Jamie is usually right.

You probably don't have a 2" NPT tap lying around, but I might be willing to lend you mine if you'll pay for the shipping back & forth. It's not like I use it every day.

Where are you located?

RTW

I had the same, or a similar, pipe into boiler called the mud leg. Little to no pressure with an oozing leak from a prior repair the size the tip of your pinky. This site HH.com recommended using "silicone tape" available from local plumbing supply shops until such time ,after the heating season, I could replace this 24 inch pipe. Its been months with no issues. BTW id get a second, third or even 4th opinion from a qualified steam tech on your situation. My Boiler dates back to the early 60's and told it will easily last 100 years, but then that was back before controlled obsolesce. I have 80 % efficiency. BTW everything Ive read on this site suggests new boilers have a short life span. I have single pipe steam, works well after following advice from this site esp. on venting Regards, Bob