replacing radiator pipes- black steel or galvanized????


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Old 08-24-11, 10:21 AM
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replacing radiator pipes- black steel or galvanized????

Hi- this is my first post- replacing radiator pipes in an rowhome I bought a year and a half ago. Hot water system, old radiators themselves are in good shape and will be keeping them. The old black steel pipes coming and going to each radiator are a different story though- already patched 3 leaks w/ compression couplings for a quick fix. Now I'm redoing each bedroom one room at a time and while I had the floorboards up I figured I better replace the pipes. Was initially told to put in glavanized pipes and fittings as it would resist corrosion better than black steel but was later told (after I had all lengths cut and fittings bought) that code is to replace w/ black steel. So what's the deal with this? What's code? Which is a more appropriate material in this case? If I go forward w/ galvanized could it be a problem during a home inspection when it comes time to sell the property? Thanks for reading!
 
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Old 08-24-11, 11:43 AM
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As far as I know you can use copper.... Its a hot water system and not steam correct?

Mono flo tee system? Two tees at each rad?

Possibly a gravity system? Large pipes?

You can convert to a pumped system...

Boiler may be old then. You should do a heat lose calc of the home and replace boiler, and possibly install copper finned baseboard...



Mike NJ
 
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Old 08-24-11, 12:58 PM
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If you've had to repair leaks in steel pipe, I suspect you have a steam system. It's rare to have leaks in the pipe with either steam or hot water but more common with steam. In either case, black steel is the prefered material.
 
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Old 08-24-11, 02:15 PM
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Agree - black pipe is preferred, at least over galvanized. Removing the old black pipe will be a chore - you'll need a pair of 24" pipe wrenches and probably a sawzall.

If your black pipe in a closed, hot-water system corroded and sprung leaks, I would suspect that there was not effective air removal devices on your system. Photos, including the expansion tank and near-boiler piping would help.
 
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Old 08-25-11, 12:49 AM
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Thanks a bunch for your replies thus far!

Lawrosa- yeah, definitely hot water system. Gravity, not mono-flow. What are the advantages to converting to a pump system? Boiler is very old, am definitely going to replace as soon as I can. As a side note, have entertained thought of splitting the system into two parts- one line committed to upstairs and another for downstairs w/ a thermostat committed to each primarily due to heating imbalance (upstairs gets mega hot, downstairs still cold). To do so seemed like it would require two boilers, one for each line- seem crazy?? Only a thought, not a plan in action by any means...though would be relatively easy to switch to if advantageous as it will only require pipes being re-routed in basement. Considered copper briefly but chose against it due to cost difference in material (copper's high!) and it seems like I see that in place mostly as patch-work. This system is ~85 years old; though reliable, copper and soldered joints don't seem like they would last as long??

Grady- yeah, like I said, definitely hot-water, I think it's just so old that it's starting to fail; 2 of 3 leaks were joints close to outside-facing walls and susceptible to the cold, I'm sure the house sat unused and vacant for at least one winter before I bought it.

Gilmorrie-agreed, removal was a chore, there was no wrenching anything loose as it was so old and all threads were corroded to a dead-lock. Used angle grinder mostly as sawzaw blades didn't last long. Cut things out to a flange that isolated back bedroom and kitchen from the rest of the line, kept 1/2 of the flange on and cleaned it up real nice-like and started rebuilding from there as that part of the line will get replaced sometime in the next 6 months theoretically. Will get pics up as soon as I can; near-boiler pipe is solid. Expansion tank is still kicking but could use a replacement. What's used now, a similar metal expansion tank in the same area/position or one of the rubber expansion bladder things I saw?

So I understand that black steel is preferred but will the galvanized actually corrode and fail faster? If a home inspector were to see galvanized there at least partially would it get flagged? I'm just trying to make absolute sure before I start returning all this stuff. Thanks again!
 
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Old 08-25-11, 07:21 AM
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IMO I think you are wasting your time. effort, and money

Now that the pros know its a gravity water system you will get oodles of advice.

Do a heat loss calculation first. Size a new boiler. Decide to keep the rads or not. Then cut out all piping up to the rads or run baseboard. Run your 3/4 copper loops that you can zone. 2- zone, 3- zone... Whatever... etc...etc...etc...

Good luck.

Mike NJ
 
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Old 08-25-11, 08:08 AM
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Originally Posted by skip dandy
So I understand that black steel is preferred but will the galvanized actually corrode and fail faster?
Neither type will fail provided you have effective air removal devices - which you probably don't have. Without effective air removal, either type of pipe and your boiler, too, will fail.

There is nothing wrong with using galvanized pipe, but it is a waste of money.
 
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Old 08-25-11, 05:35 PM
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Keep the radiators. They are a great source of heat. You can make two zones for sure with one boiler. I did the same in my house a couple years ago.

The reason you don't need galvanized is because when the water is heated, the oxygen turns into air bubbles. With the proper collection devices, the oxygen is removed and released to the atmosphere. Without the oxygen, you will have no rust.

Consider using an oxygen barrier pex when you replace all the piping.
 
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Old 08-26-11, 05:21 AM
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Drooplug- would you mind summarizing how you zoned out your system with one boiler? Agreed, I have no problems w/ the old rads, they seem classy.
 
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Old 08-26-11, 06:19 AM
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Skip, google the term "zone valve" and you will be rewarded with tons of reading.

Basically they are electric valves that open and close on demand from thermostat and direct the flow through piping 'zones'.
 
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Old 08-26-11, 05:23 PM
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This is extremely common. Like trooper said, you would have two zone valves. When the thermostat makes a call for heat, it sends s ignal to the zone valve to open. Once the valve is open, the signal continues to the boiler to turn the boiler on. Only requires one pump.
 
 

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