# Black iron and galvanized pipe



## Tony H (Feb 11, 2008)

After considering costs, operation and appearance I have decided (I think) to use black iron out in the shed where the boiler is located and copper in the basement to connect to the DHW and exchanger in the forced air furnace.
After looking at the fittings available in the local plumbing and hardware stores it appears that the selection of galvanized is larger than black iron however the cost is a bit more, I have looked but have not found any info related to using galvanized pipe with boiler and also mixing the two types of pipe.
Hoping for soem help in answering these questions.

Is it ok to use galvanized pipe for the boiler connections ? 

Should dialectric fittings be used when connecting to copper ?  or brass ?

What about mixing black iron and galvanized ? 

Thanks for all your input
Tony


----------



## Eric Johnson (Feb 11, 2008)

Depends on who you ask, but my understanding is that galvanized is probably OK if you don't have glycol in your system.

If you go to a plumbing supply house, you can get all the black iron fittings and pipe you want or need. That can save you quite a bit over shopping at the big box stores, as you can get the fitting you need, instead of having to cobble two or three together. That can get expensive, even with black iron.


----------



## Corey (Feb 11, 2008)

I'm not a boiler engineer, but on the various metals, I can say it will really depend on how much of each you intend to use.  Looking at the galvanic series for the metals you mentioned, they would be:

galvanized steel/iron > iron pipe > yellow brass > copper > bronze

This is in order from most easily corroded on the left to least easily corroded on the right.

This also depends quite a bit on geometry.  If you have one galvanized fitting on a run of iron pipe, that galvanized coating will be corroded in short order.  If you have one iron fitting on a run of galvanized pipe, the galvanizing will hang around for quite a long time.  Likewise one iron fitting on copper pipe, the iron will corrode pretty quickly, while one copper fitting on iron pipe, the copper will stay around for quite a while. 

It will also depend a bit on your system - if you fill up with water and run that water for a long time so it becomes fully degassed and is properly treated, the system will have a long, healthy life.  If you continually add make-up water (with fresh oxygen, co2, etc dissolved) it can lead to additional corrosion.


----------



## leaddog (Feb 11, 2008)

I've found that if you go to farm auctions and yard sales you can pick up pipe fitting by the bucket for almost nothing as people use very little pipe anymore. I've bought lots of it and when I need something I usually have it. Tons of  new iron pipe fittings are going to the scrap yards because very little is being used in the factories so if you do some looking you just might save your self a bundle. 
leaddog


----------



## Tony H (Feb 11, 2008)

If I can avoid using glycol by running the pump and putting water thru the exchanger that's in the furnace I will, but there is a possibility I may need to at some time so I should stay away from Galvanized. Sounds like all black iron would be the way to go and if I can hit some auctions maybe save a bunch of cash.

A couple more Q's 

Any reason I should use ball valves over gate valves ? The price difference is quite a bit.

When running the pump to put water thru the hx in the gas furnace to keep it from freezing during a vacation or such do I need some sort of bypass to get water past the termovar valve ?

Thanks for your help


----------



## Eric Johnson (Feb 11, 2008)

The big advantage of ball valves is that you can tell by looking at them what they're set at. With a gate valve, you have to seat the valve to know where you're at, and by then, you forgot where you were. So ball valves are better for any application where you may not be all-open or all-closed. Not having any empirical data to back up my preference (what else is new?), I would tend to trust a gate valve in applications where a good seal is essential. My impression is that ball valves are more prone to leaking, especially after they've been sweated and re-sweated a couple of times. Crap in the water can scratch the ball, causing the seal to leak.

If you're going with black iron, get some threaded gate valves (ball valves come that way, too) and you'll save a bunch more by not having to buy thread-to-sweat adapters. A 50-cent black iron nipple is a lot more fun to buy than a $5 sweat-to-thread adapter.

I got 8 1" threaded gate valves for $50 on Ebay (an Ebay store, not an auction), shipping included.


----------



## Tony H (Feb 11, 2008)

For sealing the threads on black iron is teflon tape ( yellow ? ) or pipe dope like rectorseal better ?

Thanks  Eric  the gate valves I was looking at were threaded and would be open except if a repair is needed. Thats a great deal compared to about 15.00 ea at the local store.


----------



## Eric Johnson (Feb 11, 2008)

Either one; sometimes both.

I usually use teflon tape, but if I'm not sure about a joint or if it's giving me trouble, I'll put down a layer of dope, some tape, and then maybe another helping of dope.

Be careful cranking on those brass valves They're not as strong as the iron, and they can crack if you tighten them too much. I've had iron fittings crack as well. Smaller sizes should be spun with smaller wrenches, in other words.


----------



## leaddog (Feb 11, 2008)

Tony H said:
			
		

> Any reason I should use ball valves over gate valves ? The price difference is quite a bit.
> 
> 
> Thanks for your help



I like ball valves if I'm going to open and close them alot as the gate valves tend to leak at the stem under use. When buying valves look for ones that have large opening in the valve or else you will choke the flow. Some valves have 1/2 in openings on a 1in valve etc. Also don't use valves with rubber seats for opening and closeing alot as you will have to change seats over time. Gate valves tend to give better control on partial opening than ball valves as ball valves work better open OR closed. Auctions, yard sales, ebay are the place to buy.
leaddog


----------



## mtfallsmikey (Feb 12, 2008)

Ball valves are positive shutoff, gate valves MAY shut flow off at first, but usually leak thru after awhile. Gate valves are better for balancing/flow adjustment than ball valves. Make sure you use full port ball valves (full opening size vs. reduced).


----------



## slowzuki (Feb 12, 2008)

A gate valve or ball valve is not meant to balance flow, that is what globe valves are for.  Regulating flow with a gate valve can damage the seat over time and are very finicky to get a specific pressure drop across it for balancing.


----------



## Tony H (Feb 16, 2008)

One valve will be used to adjust flow ahead of the termovar valve the other valves are all shutoffs to be used when repairing or replacing parts and servicing the system so they should be used very little. Would it be best to use a globe valve and the rest gate valves or ? I did get one valve with my order a ball that is intended for use in balancing.


----------



## heaterman (Feb 16, 2008)

Tony H

Use Black pipe it's less expensive and Galvanized can break down under certain chemical conditions. Bare steel is pretty inert if you monitor your water quality and composition as you should.

Buy your supplies from a supply house, not Wally World or Home Despot, there's a difference plus a supply house will have reducers and fittings that the other places don't know exist.

Don't mix galvanized and black. I've seen some really weird corrosion in systems like that. Dissimilar metals sometimes don't like each other.

No need for Dielectric unions if you follow the next piece of advice. They always wind up leaking anyway after a few years. 

On the subject of corrosion, we always drive a separate ground rod for the equipment and bond it to the boiler itself and the piping.

We use Loctite #55 thread sealing cord and a lick of whatever pipe dope for a guaranteed drip free joint. You can get it from any WW Grainger store.

I love the look and durability of a well made up black pipe installation. Can't beat it.

The cheap ball valves you get at HD, Lowe's or other big box are junk. If you can find a supply house that sells Webstone, Apollo or Legend.......well maybe not Legend........ ball valves, those are what you want to use.
Gate valves are obsoleteIMHO. Globe valves are what you use for throttling or balancing. Ball Valves are best for general use as they don't erode lover time like a gate does.

Heck, e-mail me a material list, I distribute Webstone valves and Ward fittings. I'll get you the right stuff. 

We run into a lot of imported fittings that aren't even bored straight. You thread a nipple into an ell or tee and the thing takes off about 5 degrees from plumb. Aggravating to say the least when you're trying to be fussy about a job.


----------



## slowzuki (Feb 18, 2008)

If you use mostly black steel, don't mix one or two galvanized fitting in, they will be attacked.  If you use mostly galvanized, its fine to mix a few pieces of black in.

If you don't have much copper, use a good thread sealant and you'll likely be ok.  If you have a lot of copper, ie more than the steel you're using, it will rot out the steel if you don't have a dielectric coupling.


----------



## BOOO (Feb 18, 2008)

Before I retired a rep came in and gave us a seminar on the Loctite products. Loctite 561 pipe stick worked the best for us. We stopped using Teflon tape.
As I understand the tape acts like a lube so as to get tighter. With the 561 it seals without cranking on the fitting as hard. Used it on water,air and hydraulics.
It also comes apart easier,it doesn't set up.
On my wood gun the 1 1/2'' copper male that fit in the boiler had several layers of tape and dope and still only had a couple threads showing so as not to leak.
That was before 561, just a good product.
Have anyone installed screens in line to collect corrosion particles?


----------



## slowzuki (Feb 18, 2008)

I'm thinking of a basket strainer if I can't flush the lines out really well first.


----------



## ISeeDeadBTUs (Feb 18, 2008)

Not sure how competitive their prices are on black, but NutsandBolts.com sells the stuff. I was looking for something else there when I found it.


----------



## steam man (Feb 18, 2008)

Nothing beats having good dies for threading pipe and doing it properly. I hate seeing overtightened fittings to control a leak. You actually can ruin the thread causing more problems. Any premium pipe dope/tape works well with proper threads.


----------



## slowzuki (Feb 18, 2008)

True pipe threads are designed to be tapered and seal without sealants but I don't know anyone who would design on that basis these days!  I like looking at the hundreds of 1" perfectly welded pipe in older power plants.  Some of the work is just beautiful, no body welds stuff today though.  Thread or grooved.


----------



## steam man (Feb 18, 2008)

slowzuki said:
			
		

> True pipe threads are designed to be tapered and seal without sealants but I don't know anyone who would design on that basis these days!  I like looking at the hundreds of 1" perfectly welded pipe in older power plants.  Some of the work is just beautiful, no body welds stuff today though.  Thread or grooved.



I feel like a dinosaur............................

Interestingly enough I do a lot of pipe fitting on ships and much of it is welded. It's just easier to get the fit up perfect (to me any way). Pipe fitting tends to be one of my favorite jobs among many. My dad was a professional pipe fitter and I was doing lead joints on sewer lines by the time I was ten. I am thinking about welding up much of my wood boiler install.

BTW-check out a wye-strainer and maybe just put a blow down valve on it.


----------



## slowzuki (Feb 19, 2008)

Thats what I was thinking for a strainer, I spec them on water supplies here and there when we can't flush the lines.

I love the workmanship that goes into a nice welded joint, I've never had much luck getting one to look nice myself but I'm too cheap to buy some nice capping rod!  I looked into welding but PEX is so cheap and fast and freeze resistant its hard to justify welded.


----------



## Tony H (Feb 23, 2008)

Thanks for all the comments ,it looks like black iron and ball valves are the way to go for the boiler end out in the shed. For the basement end from the PEX to the water heater , exchanger and DHW mixing valve I was planning to use copper to match whats there.
Are the brass valves ok to direct connect with threaded connections to the black iron ? 

I hope to get a couple of pictures and a drawing going to explore some options on design like themostats, freeze prevention, overheat prevention and timers / aquastats


----------



## steam man (Feb 23, 2008)

I came across Fred Seton's site http://www.radiantdesigninstitute.com/page42.html. The site makes for really good reading.

DIELECTRIC UNIONS:  

    Here is a very misunderstood fitting, that is seldom used properly. The problem that a dielectric union is suppose to solve is a dissimilar metal problem between steel and copper, such as a steel water tank and copper pipe. Dielectric unions in a hot water heating system are nothing but trouble and usually leak in a short time. The antifreeze, boiler additives or acid water conditions cause the gasket to deteriorate.
   There are better ways to handle this problem:  FIRST REMEMBER THAT COPPER HAS NO PROBLEM WITH BRASS OR CAST IRON, IF YOU PUT A BRASS OR CAST IRON FITTING BETWEEN THE STEEL AND THE COPPER THE PROBLEM IS SOLVED. EVEN ON A HOT WATER TANK, A BRASS NIPPLE OUT OF THE TANK WOULD BE THE BEST CHOICE.


----------



## Eric Johnson (Feb 23, 2008)

I assume that includes brass valves and fittings? Or are most of them bronze?


----------



## steam man (Feb 23, 2008)

Eric Johnson said:
			
		

> I assume that includes brass valves and fittings? Or are most of them bronze?



I believe he means brass or bronze, fittngs or valves. In my experience with large made up flanges of cupro nickel material mainly, when steel bolts are used across a gasketed flange bonding straps jumpered across the flanges reduce the galvanic action on the steel. Some salt water systems are designed with a "waster" piece of a heavy gauge short steel section to be replaced periodically. An electrical engineer friend of mine has taught courses on corrosion control. There can be a lot to it.


----------



## deerefanatic (Apr 17, 2008)

So what you guys are saying is that we're better off using "black pipe" like they use for propane gas lines than to use galvanized pipe for hydronics? That seems crazy as they always say that black pipe will rust away whereas galvanized is "more" rust resistant.......

But hey, if the black pipe works better, that's what I'll use since it's soo much cheaper...... Crazy............


----------



## jebatty (Apr 18, 2008)

> using "black pipe" . . . That seems crazy as they always say that black pipe will rust away whereas galvanized is "more" rust resistant.



An earlier post on this thread got to the meat of this - it's all about conditioning the water, which mostly means keeping the alkalinity up, scavenging the O2, and buffering. All pretty straight forward in a closed system. An open system will need more attention if using iron pipe or a steel storage tank, as it is constantly open to more O2. 

Tarm recommends pH 8.2 (alkaline). Acid is a killer for iron/steel. Tarm doesn't comment on the O2, and I'm guessing that's because it is to be a closed system, and any O2 quickly will be consumed with minimal rust, and that's done. An O2 scavenger certainly wouldn't hurt, as the system may be subject to some venting between full heat and cooling down.

For those concerned about bits of corrosive material circulating in the system, wear on pumps, etc., you can get 200F rated hot water filters, similar to a house water filter, or put a strainer on the line. A 100 micron screen should be OK, just clean it from time to time.


----------



## deerefanatic (Apr 18, 2008)

Hmm... I wonder if the alkalinity chemicals for pools would work to keep alkalinity up? I familiar with them as I was put in charge of tending the needs of the family pool for the last 5 years we had it........

For the O2 concerns on a non-pressurized system,  (which I will be using) I'm pretty much sold on Nofossil's idea for floating melted wax on top of the water in the expansion tank.... That would be like a bladder tank without the pressure.....

I think I'll look into the strainer idea...... Then again, maybe not.


----------



## GARYL (Apr 18, 2008)

For what it's worth I recommend ball valves, especially if you will use them infrequently. When I installed my underground well house alotta years ago I used all gate valves. Several years later I had to replace the pump and none of the gate valves would move and some of the handles broke off. I replaced them all with ball valves and have gone several years without using them and when I do they work just great. Just my two cents. 

Good Luck,
Gary


----------



## deerefanatic (Apr 18, 2008)

Definitely... Ball all the way for me... Pexsupply.com sells ball valves for LESS than gate valves!! No brainer there.......


----------



## heaterman (Apr 18, 2008)

Steel piping tips:

Use black only and do not mix with galvanized. Black holds up just fine. I can show you dozens of 50+ year old black pipe systems that have never had a failure of any kind. Not uncommon to see steam systems that are 80 or better. Galvanized reacts with too many things found in a hot water system.

Say NO to di-electric unions. period. you don't need them on a hot water system.

LocTite #55 thread cord and a lick of your favorite pipe dope will seal anything. Even straight cut Euro threads.

Bond your steel piping system to an earth ground.

If possible use fittings that are made in the USA. Ward fittings are good. Lot's of the import stuff is not even bored straight. Your pipe will take off on an angle and look like heck.

Use a Wye strainer to catch debris in the system and check it often the first couple years. It'll catch anything big enough to cause problems in a circ or zone valve.

Monitor you system water quality for PH levels at least annually. For a typical iron and steel system you want your water to be 7-7.5


----------



## jebatty (Apr 18, 2008)

> Hmm... I wonder if the alkalinity chemicals for pools would work to keep alkalinity up? I familiar with them as I was put in charge of tending the needs of the family pool for the last 5 years ...



I've thought about pool pH add also, which, at least the brand I saw, was calcium carbonate. Who can answer this specifically? I note that boiler chemicals that I have used do not contain calcium carbonate. But I think you need more than just calcium carbonate to buffer pH changes.

I think sodium sulfite is the chemical of choice for an O2 scavenger.


----------



## heaterman (Apr 18, 2008)

PH adjusters:
 There are better ways to go than pool chemicals. Go to a heating supply house and see what they have. A good boiler water treatment will have O2 scavenging capability, some lubricant and anti-corrosion additives plus the PH adjuster. A boiler system is not the same as a pool and shouldn't be treated as such.
 Before treating any boiler/piping system, it should be thoroughly flushed, then heated up with a good cleaner in the water, then drained and refilled with your additive package. 
Treat a properly installed, good quality boiler system with care and it will outlive you.


----------



## Tony H (Apr 19, 2008)

Heaterman,
On my application I will have black iron in the shed then pex pipe to the basement and a copper sidearm hot water exchanger and an copper exchanger in the forced air furnace so should I use copper or BI to make the connections from the pex to the exchangers ? 
Copper is what I was planning but now I am wondering?
Thanks


----------



## heaterman (Apr 20, 2008)

Tony H said:
			
		

> Heaterman,
> On my application I will have black iron in the shed then pex pipe to the basement and a copper sidearm hot water exchanger and an copper exchanger in the forced air furnace so should I use copper or BI to make the connections from the pex to the exchangers ?
> Copper is what I was planning but now I am wondering?
> Thanks



We use Black iron around the boiler for strength and rigidity, then if we are running underground pex is obviously the choice and once in the house we go to copper. Sometimes if the manifold warrants it, we use iron pipe off the pex mains and then back to pex or copper. 
Anymore, I really like the PAP products like Fosta-Pex from Viega. It's pex, then a layer of aluminum, then pex on the outside again. Stays a lot straighter and the expansion ratio is nearly the same as copper. It doesn't droop like a boiled noodle when you put the heat to it. 
All that being said, you can go directly from pex to the copper HX's you are using. No need to adapt back to iron.


----------



## Tony H (Apr 21, 2008)

Thanks, the Pex I have is the PAP stuff and it seems pretty stiff and stays straight when I straighten out a length of it.


----------



## deerefanatic (Apr 21, 2008)

Yah, but PAP is sooooooo expensive............. Good, but expensive...........

oh well, what isn't these days?

I think I'm just going to use all copper & brass where I can.. Yah, it's more expensive at the outset, but it's lifespan is nearly infinite........


----------



## jebatty (Apr 21, 2008)

And just wait until the report comes out that the plastic used in Pex is harmful in some way, just like Nalgene water bottles and other hard plastics are now under high suspicion. 

http://online.wsj.com/article/SB120873770422129987.html?mod=googlenews_wsj


----------



## heaterman (Apr 21, 2008)

deerefanatic said:
			
		

> Yah, but PAP is sooooooo expensive............. Good, but expensive...........
> 
> oh well, what isn't these days?
> 
> I think I'm just going to use all copper & brass where I can.. Yah, it's more expensive at the outset, but it's lifespan is nearly infinite........



If the PAP you're buying is a lot more costly than regular pex, you probably have some really junky pex or else the wrong kind of PAP. Among the better brands of plastic tubing, there's not much difference at all. Pennies per foot actually. The only brand of PAP, that I know of, that is a lot more money is Kitec. I don't recommend it due to some issues they've had with their product as well as the cost.


----------



## deerefanatic (Apr 21, 2008)

Yah, for drinking water, I'll stick with copper for good...............

But this is HVAC water.... Don't intend to drink this stuff!


----------



## deerefanatic (Apr 21, 2008)

Well, I found HydroPex 3/4" in 300ft spools for $129.95 each...... PAP is ALOT more than that............ And the HydroPex is certified by all the major HVAC Pex certifications........


----------



## Yates (Jul 16, 2008)

Has anyone out there found a good source for 1-1/4" pex with O2 barrier?  I've been on line and most stop at 1" stock.


----------

