Black iron and galvanized pipe

[deerefanatic]

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]

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]

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]

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]

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

 

[heaterman]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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

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

 

[deerefanatic]

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]

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.