Will stainless steel nipples work well in near-boiler piping?

sbachman7117

The 20-year-old piping near my W-M steam boiler rotted out and I need to rebuild it. I'm considering using 304 stainless steel nipples with the old iron fittings (1-1/2".) Is this a good idea? If not, how about SCH 80 black iron? I believe the nipples that rotted out were SCH 40. I don't want to do this job again in 20 years...
Thanks for any advice!

SWEI

They will work just fine. We're using more and more 304 SS fittings of late -- they actually cost less than brass does these days.

Steamhead

Which begs the question- was this on the steam or the return line? If the former, what made the old pipes rot out?

sbachman7117

Here is a photo of the condensate return piping, before I removed it. The 2nd photo shows the tee that (along with many of the nipples) rotted out. In the "before" photo, that rotted tee is wrapped in various sealing tapes. I'm inclined to eliminate that tee and the horizontal capped nipple, and just use an elbow where the condensate returns to the boiler. The Weil-McLain EG-45 manual shows an elbow. I suppose the tee/cap was used to allow access for cleaning, but not sure. There is also a fitting on the opposite side of the boiler that may have something to do with cleaning (3rd photo.) I have never cleaned the boiler, beyond weekly blow-downs.
Again, any thoughts or comments are welcome!

ChrisJ

With the fittings rotted out and it appears even the boiler jacket is rotted out around things, how is the block not rotted out!?

Why is that water so corrosive?

MichaelK

Looking at your before pic, is the copper line your condensate return? I would recommend installing dielectric unions, then bringing the two lines into the tee that feeds the equalizer. Electrolysis could have caused the rot if no leaks were present.

Are you using a feed pump? Also is there any type of chemical treatment being used? I've seen something similar on commercial HB Smith. Rotted out half the equalizer, the 90 and half the yolk in the back. Copper to steel causes problems down the road.

Could you submit a picture including more of the near boiler piping?

Just an idea. Good luck. Send after pics!

-Mike

sbachman7117

CORRECTION: The manual DOES show a capped tee on the condensate return port for the EG boiler. (I had been looking at the EHG diagram.) Diagram is attached. My piping differs in 3 ways from the diagram:

1. My equalizer (J) starts at a 45 degree angle to vertical.
   
2. My condensate return comes in vertically and forms a trap (u-shape) prior to joining the equalizer line.
   
3. My condensate connection to the tee at the inlet is vertical, rather than horizontal, as shown in the diagram.
   

Another thought: Rather than using stainless nipples, would it be advisable to use galvanized fittings and nipples for the portion of the piping below the water line? I could use 1-1/2" dielectric nipples (plastic lined) for the connections to the boiler, equalizer and condensate return line. Smart? Stoopid?
Thanks!

MichaelK

I'm assuming it's gravity return based on the time it took to rot. If it was electrolysis then just replace what rotted and install the dielectric unions. You won't need stainless or galvanized.

Pics of near boiler piping?

SWEI

More info needed here -- what are the pH and chloride levels like in your water? Is there a water softener in use? Are there other leaks in the system which are causing the autofeeder to run a lot?

Dielectric unions have issues. If you need to transition from steel to copper and have real galvanic corrosion issues there are a number of other options worth considering.

sbachman7117

Thanks for all the help! To answer the Q's you guys had:
Steamhead - The rot is on the return line.
ChrisJ - Not sure about how rotted the core might be...(fingers crossed!) The heat exchanger was replaced under warranty in 2001. The near-boiler piping was installed with the new boiler in 1993, so it's older than the core. The water is Ann Arbor, MI City water, which certainly has a reputation for being tough on plumbing, but I don't know the chemistry details.
JohnWayne - The copper pipe is 1/2" makeup water feed. The 1/2" tee is galvanized. Inputs are brass (auto-feeder, horizontal leg) and copper (fast-feed, vertical.) Output is black iron into 1/2x1-1/2 tee on condensate return line. Photos attached. Makeup water is straight city water.
There was a steam leak in an upstairs radiator last winter, that went unnoticed for probably a month or so. (Condensation was freezing in the wall/floor cavity.) So, lots of feed water for that period, which probably accelerated the rot.
Thanks again!

SWEI

sbachman7117 said:

The water is Ann Arbor, MI City water, which certainly has a reputation for being tough on plumbing, but I don't know the chemistry details.

Your water department reports an average 112 ppm chloride level. That's more than 304 SS is really happy with I would suggest you consider filling the system using either RO or bottled water, and make sure the system uses very little makeup water. You might also want to consider chemical treatment.

sbachman7117

Thank you! Once I re-pipe, I will figure out how to get bottled water in there. I guess I can attach a hose to the boiler drain and pour the bottled water in through the hose. I suppose I could also shut of the automatic water feed and manually add bottled water when I do the weekly blow-downs. Kind of a hassle...
Short of that, what do y'all think of doing blow-downs less often while continuing with the high chloride City water make up? (To be honest, I've never known why weekly blow-downs are recommended, considering that they introduce new oxygen and other nasty stuff each time.)
Is there some kind of small-scale in-line water softener designed for small residential steam systems?
As always, THANKS!

hot_rod

sbachman7117 said:

Thank you! Once I re-pipe, I will figure out how to get bottled water in there. I guess I can attach a hose to the boiler drain and pour the bottled water in through the hose. I suppose I could also shut of the automatic water feed and manually add bottled water when I do the weekly blow-downs. Kind of a hassle...
Short of that, what do y'all think of doing blow-downs less often while continuing with the high chloride City water make up? (To be honest, I've never known why weekly blow-downs are recommended, considering that they introduce new oxygen and other nasty stuff each time.)
Is there some kind of small-scale in-line water softener designed for small residential steam systems?
As always, THANKS!

You should be able to find DM de mineralized water locally. Call around to Culligan or other water treatment folks,most have large DM units and will sell water in 5 gallon or larger drums.

RO is a bit overkill and drops ph too low. You might want to add a buffer or hydronic treatment to water that pure.

The next Idronics issue, #18, will be on water quality in hydronic systems.

ChrisJ

Rhomar sells what they call "Boiler Fluid" for steam boilers.

MichaelK

I would still recommend the dielectric on the feed line. The verticle quick fill isn't really and issue, just the make up line. Sounds like you got it solved. Good luck. Also keep doing the blow downs. They are worth it.

Also as hot rod stated if you fill manually find demineralized water.

sbachman7117

Great help! I will use demineralized water and will look into the additives suggested. Any thoughts on using "Powder Boiler Seal" (from Solder Seal / Gunk)? I happen to have a can of it, but I've never used it before. The label includes: "Highly recommended for new installations." Apparently it forms some kind of coating on the portions of the system below the water line...? Not sure what else it might do, regarding water chemistry. Any experience with it?
Thanks!

ChrisJ

@JohnWayne I've heard many say dielectric unions more often than not fail before a direct copper to cast iron connection and many pros refuse to use them. On my own system I just went copper right to cast iron but kept all of the fittings going directly into the boiler as black iron. This should keep most if not all of the attack on the cast iron fittings away from the boiler.


@sbachman7117 Sorry, my previous reply was typed on a phone just after I woke up. The product you may want to consider is Rhomar STEAM-PRO. It's a premixed "boiler fluid" as they call it. It contains quality water and treatment all in one. The thing I don't know is what do they want you to use for makeup water. I would assume you can't just keep adding the STEAM-PRO fluid, but who knows.

http://rhomarwater.com/media/W-SteamPro.pdf

sbachman7117

Thanks ChrisJ. I spent some time on the Rhomar site this morning. I have a call in with them, to see if their products are available locally. IIRC, the instructions for Steam-Pro (pre-mixed) say to use tap water for make-up, but then incrementally add the 930 product (concentrated version), based on testing the water. Strangely, the 930 instructions call for periodic 3-5 second blow-downs of all valves, while the Steam-Pro instructions say the blow-downs are normally not needed during a single heating season. The latter presumes (I think) that 930 has NOT been added to the Steam-Pro. Kinda confusing, but I hope to get find the Steam-Pro locally and then minimize blow-downs. Maybe...I'm learning more everyday and my plan changes accordingly!

SWEI

Call Rhomar and ask them specifically about chlorides.

Fred

sbachman7117 said:

Great help! I will use demineralized water and will look into the additives suggested. Any thoughts on using "Powder Boiler Seal" (from Solder Seal / Gunk)? I happen to have a can of it, but I've never used it before. The label includes: "Highly recommended for new installations." Apparently it forms some kind of coating on the portions of the system below the water line...? Not sure what else it might do, regarding water chemistry. Any experience with it?
Thanks!

Don't use any of those sealer additives at all. They only create headaches!

sbachman7117

Thanks Fred. I'll throw away the Powder Boiler Seal. I don't need any more headaches!

ChrisJ

Fred said:

sbachman7117 said:

Great help! I will use demineralized water and will look into the additives suggested. Any thoughts on using "Powder Boiler Seal" (from Solder Seal / Gunk)? I happen to have a can of it, but I've never used it before. The label includes: "Highly recommended for new installations." Apparently it forms some kind of coating on the portions of the system below the water line...? Not sure what else it might do, regarding water chemistry. Any experience with it?
Thanks!

Don't use any of those sealer additives at all. They only create headaches!

What kind of problems have you had with it?

Fred

I have never used any sealers in my boiler but I have a couple neighbors who have tried it. One said the smell carried in the steam and it smelled for several weeks, the other said they had to drain the boiler, flush, refill it and skim a few times to get the water reasonably stable. They may have put too much in, I don't know but most of those additives are not anything I'm willing to even consider. Besides that, I don't know how those chemicals play with things like Steamaster tablets.

j a_2

Get rid of the automatic (as you call it) water feed...All's it most likely is doing is masking excess water usage... Find and fix the leaks...get the water ph stable and be done with it....no real need for anything but the good old cast iron fittings and some good d American made black steel pipe...good luck on the redo...

gennady

No need to install stainless steel, just watch pH level of boiler water, treat if necessary. Do not directly connect black steel with copper, only through brass fitting. Dielectric unions usually leaking with the time.

sbachman7117

Thanks Gennady and j_a. Last night I completed the re-pipe using USA-made black pipe and fittings. (I ended up putting a galvanized union on the 45 degree section of the equalizer, simply because I happened to have one on hand, after I broke the old one. Doh!)
I flushed the boiler with TSP and ordered the Rectorseal Steamaster tablets for conditioning. I will shut off the WF2 water feed and will fill with demineralized water plus 1 Steamaster tablet (W-M EG45 boiler.)
Finally, I will pray that I haven't done too much damage to the core by previously using untreated Ann Arbor City water in it since 2001!
THANKS AGAIN to all y'all!

Fred

Even though you flushed it with TSP, there is a high probability that the boiler will have to be skimmed as there will be some residual oils from the new fittings. Watch the sight glass and see how much bounce you get in the water after a week or so. My boiler is very sensitive to even one new fitting and has to be skimmed.

sbachman7117

Will do Fred. Thanks for the heads-up! In retrospect, I probably should have soaked those new fittings in degreaser prior to installing.

MichaelK

Sounds like a job well done.

As far a dielectric fittings go. I've not had bad luck myself but working commercial I don't always go back. I have heard of dielectric fittings used on anything but domestic or chilled water will leak.

Also I was told you could go copper, stainless union, brass fitting, black pipe and that would work the same. Thoughts?

sbachman7117

I've mostly just used brass between copper and galvanized, for potable water in older houses with existing steel pipes. The Ann Arbor inspectors sometimes require dielectric unions on water heater connections, but they often rot in spectacular fashion. I hate dielectric unions and the feeling seems to be mutual, so I use the flexible SS couplings on water heaters. I wish there was something that easy for boiler connections.

SWEI

Depends a bit on the water chemistry, but sometimes just a foot or so of either brass or stainless will do the trick. An inch is not the same as a foot.