Cast Iron Fittings

Rogush

Can I/should I use cast iron fittings on condensate return?

ChrisJ

Just a homeowner, NOT A PRO.

but I think you can use almost anything as long as it is metal for this.



Personally I used copper below the water line.

Rod

Return Piping

The pros seem to be split on this. Some use black pipe and cast iron fittings on the wet return and some use copper. Iron has the advantage in that its walls are thicker so can tolerate some corrosion. Copper piping has the advantage that it stays cleaner internally as crud doesn't stick to it like it can with black pipe. (We're only discussing piping below the boiler's waterline as pipes bearing steam should be black pipe with threaded cast iron fittings)  I would make sure that any Wet Return pipe you install is not placed straight on the basement floor but raised a bit. I used 3/4 inch wood blocks with a piece of plastic I cut out of a plastic milk bottle between the wood and the pipe. The reason you want to raise the pipe is a lot of the basement floors in old houses are composed of fly ash for the coal boiler days. This, when it gets damp, is very acidic and can eat through a pipe (especially copper) very quickly. I replaced my return piping with copper and have been very happy with it.

- Rod

JStar

Return

Honestly, I only use black pipe and cast iron on the return for the looks. It keeps my entire near-boiler looking clean and neat. I hate the way a copper return looks attached to a beautiful black-pipe header. The copper also always seems to get stained and dirty looking over the years. Plus, I've never had one of my own black fittings leak. I've had plenty of copper joints leak.

ChrisJ

Uhoh

Jstar " I've never had one of my own black fittings leak. I've had plenty of copper joints leak."



Not sure how to take this? I can only assume you're talking about threaded joints and not soldered?

PMJ

Return

Use black pipe and cast fittings. Mine is 85 years old and still yet to have its first issue.

ChrisJ

wet return

My iron wet return was the first thing to go as it was clogged with gunk.

Condensate is very acidic and it doesn't get along with steel and iron as well as it does with copper.



All my dry returns are iron and have no problems.

PMJ

Acidic?

Have you measured the PH? Since the tap water starts you off at 7 where is the acid coming from? I would worry about my boiler if my water was acidic. Commercial boilers are maintained with high PH chemicals to be sure they are not acidic.

ChrisJ

PH

I maintain my boiler water around a PH of 9.

Last time I checked my wet return it was around a 5 or 6 if I recall. I don't have the article handy right now but return water is always acidic. I believe it has to do with carbon dioxide dissolving in the water as it cools returning to the boiler but don't quote me on that.



This is why it is important to insulate returns.



This is also why boiler water may start out as 7, but over time will drop. I also check the TDS of my boiler water and wet return. For example if my boiler water has a TDS of 500 and my wet return shows a TDS of 1, to me, that suggests I am producing very dry steam. If the TDS in the wet return is higher it means I have carry over. This is my understanding of it and may not be totally correct but it seems to work.

JStar

Leaks

Correct.



And now that I've said it...it's going to happen.

ChrisJ

leaks

Ever since I started using megalock dope and blue monster tape together on my threaded joints I have not had a leak. Before that I hated threaded connections.



On iron pipe I only use the dope except if I'm going into an old iron fitting like on a steam main, then I'll use both.

BobC

Maybe

it would be worth adding say 1/8 of a steam master tablet to the wet return to de-acidify it?



BTW have you seen anyplace online selling the steam master tablets?



Bob

ChrisJ

steamaster tablets

Hi Bob,



Not yet no. I'm considering switching to Rhomar's product at one point as their products seem easier to get.



http://www.amazon.com/RHOMAR-WATER-MGT-INC-Treatment/dp/B005E0MKF4



They also seem to have awesome support if you have any questions.

PMJ

PH

I've never checked my PH and I have never added anything. I am quite sure that the Bryant manual says under normal operation no additives are necessary. Water in sight glass is clear and returns as old as they are never clogged up. I think problems increase rapidly if there is much makeup water required as the new water brings in oxygen and minerals.

ChrisJ

water treatment to wet return

After thinking about it for a bit Bob I've come to the conclusion adding treatment to the wet return won't help.



You have a slow but constant flow towards the boiler. The treatment will end up in the boiler and the wet return will end up plain distilled water again.





PMJ, you have never checked your PH? I highly recommend you do so. I'm also sure Bryant says to use necessary treatment for your water which includes monitoring PH levels and there are reasons for this. On a vacuum system contamination may be much slower than a single pipe but it likely still takes place.

PMJ

check ph

I will check it and report back.

The boiler is over 50 years old and the piping over 80. I have not drained the boiler or used any additives in the 21 years I have been the one running it. Never had a reason to. I just opened a boiler drain valve the other day to look - 1 second of rust then clear as always. Bottom line, ultra low pressure in a system tight enough to hold vacuum means ultra low water losses and negligible makeup water.



BTW, I do treat the water in my 200HP boiler at the plant. There are losses with process steam and significant makeup water. It is the makeup water that drives the need to treat and blowdown.

ChrisJ

Not fair

See that just isn't fair.

The boilers like yours don't rott like the modern ones. My neighbor has an old American radiator boiler and before I started working on the system he was dumping gallons a week into it due to leaks. It just keeps going, no problems.



If I did that to my boiler it would be rotted in a year or two.

PMJ

Yea I'd Hate to lose it

And I am afraid it is as you say. Refrigerators too. And concrete. Why is it that we collectively accept this steady decline? In exchange for lower up front cost? The long term annual cost only ends up higher for everyone this way.

PMJ

Checked the PH

Tonight I drained some water from the bottom of the boiler and checked the PH. It was 8.9.

That is many times boiled tap water in a cast iron system with no additives.



The Bryant manual said newly installed boilers sometimes need considerable cleaning, skimming and blow down and stressed the importance of making sure all cleaning chemicals were totally removed. From there it said fill with clear tap water. The recommended PH was 7-8. It also said a boiler should "never" be drained between seasons and if it ever was because the water had become dirty somehow that it needed to be fired immediately to remove all the oxygen.