From new, add scale inhibitors, pH buffers and bactericides to the system.

From old, change out the knackered pipework, add in-line strainers, and then add the above.

Yes, we (the Board of Directors) have considered re-piping. But it's intrusive and costly according to our HVAC service company.

Salvaging the old pipe would be a great saving for the owners.

If re-piping was undertaken, what type of pipe would be optimal in lieu of iron pipe?

Are 'in-line-strainers' another form of filter?

Buffers and bactericides were not used for the initial 5 years, so we are playing catch-up now with them somewhat unsuccessfully.

Thanks

If you want to salvage your old pipe, try taking the blocked sections and soaking overnight in Coca-cola.

We restored a lathe that had been left in a soggy cardboard box for a couple of years after flooding. The nuts and bolts were just knobs of rust. Soaking in coke did the trick to loosen that off, and we were able to clean them up and use them after all... it might work.

Yes, I've heard of the coca cola mythology, but never related it to our condo building a/c problem.

While we do not replace sections of clogged pipe we remove with the original pieces, as you seem to suggest, what do you think would be the result if we loaded the entire pipe system (three floors with entry pipes from the mains into and from each unit, with coca cola? I suspect it would hold one to two hundred gallons!!

Does coca cola dissolve rusted accumulations, or does it only loosen up the accumulations into small pieces?

Thanks

After leaving the bolts overnight to soak, there were pieces of rust broken off as well as a rather clean and recognizable nut or bolt that only needed a little brushing and rinsing to be serviceable. They really looked pretty good, but I couldn't tell you if rust mainly dissolved or was loosened - bit of both I would guess.

Loading your system with hundreds of gallons of coca-cola sounds like a pretty crazy thing to do. You would certainly have to flush it with a lot of water afterwards, but as in our own case, a little brushing helped as well. I can't predict how hard it would be to get clumps of rust to be washed out of the pipes. Maybe you should take one of those pieces you removed, and do the experiment. See if you get dissolve rather than disperse, see how the rust handles under the expected water pressure without any scrubbing.

It's the sort of thing that would make a bizarre coca-cola ad... they might buy the rights to film your story....

I thought I saw a similar thread last week, and almost posted, but didn't.

Seeing the answers so far i'll add my thoughts.

1) Have you done a survey to see where the clogs and build ups are? how many feet out of how many feet? And which feet as in how far from either terminus?

2)are valves available that will let you isolate a section at a time?

3) starting at the end closest to the ultimate drain, the coke idea could be a good start if you closed off the bottom, measure the theoretical length to where you put in the coke to the closed end's volume, measuring the coke volume (counting the # of 2 liter bottles will help you estimate the degree of clog...

4) After giving the coke 10-15 minutes, I'd switch on a bin knocker (syntron vibrator)

SYNTRON attached to the pipe to help break loose the scale and corruption . (will make a hell of a racket.)

5) Then I'd snake it, reblock and determine if the treatment had significantly increased the pipe volume. IF so repeat.

Their are probably other makes of vibrators that would work, I am used to using these as bin knockers for bulk conveying...

good luck. And Good thinking using coca cola instead of sulfuric, which could really get someone hurt .

milo

somewhere in the first few pages of this search you might find some answers to scale removal in iron pipes.

http://www.google.ca/search?hl=en&q=plumbing++%2B%22iron+scale%22+%2Bremove+&btnG=Search&meta=

After many years in this business I 100% agree with PWSlack. Remove the iron pipes and replace them with PE/PP or PVC-pipes and use a cooling brine with corrosion inhibitors and test this brine twice a year. Immediately replace the brine if the anti-corrosion-system is insufficient. Try to avoid any metal-based devices (eg valves, armature) in your system. Since at the moment you do not know to what degree the pipes and the valves, etc are affected by corrosion and other sediments (CaCO3, CaSO4, silicates) which form very strong layers on your pipes and reduce their free diameter, too, you cannot be sure to solve this problem by applying acids and/or supersonic sound, etc. Also you may irreversibly damage some parts of your installation and cause leakages. The cost of such a treatment is also quite high and the rust/sediment-particles which are set free during this cleaning process may also block your system completely.

GA. I also wonder whether a cleaning of the iron pipes could be conducted followed by insertion of a plastic liner.

yup...a tank of pressurized coke courtesy yr local-restaurant...or bar

a stretch of hose to splice into the line.....ièd say...leave the joints....cut the pipe, feed the hose in, spud a new adapter connector onto the hose and pipe...you now have the line intact and usable as is...not to interfer with tenents...turn on the water.

you now have a lengh of pipe to experiment with.....parallel to the hose...or what-ever...ièd connect the lower end and fill----when it comes out the other end...stopp let it stand twenty plus hours...calculate...record etc...when you drain...i would to the coke end, also weigh samples and analyze....if you got a sloppy sludge...ok if its a scale load....oh kay

hereès a try...with extra valves so you can bubble-air water through after coke, the bubbles will scrubb....but you may need to alternatelly blow from each end.

iève often wonderd about electrical rust inhibitors used on autos bluck

Leave the old pipes and re plumb with the plastic "PEX" http://www.ppfahome.org/pex/faqpex.html

This stuff is awesome and will be soooooo much easier and affordable. I am sure this will satisfy you and your board.

Josh.

These tubing systems have had a lot of problems in the past. They have been known to develop slow leaks causing all manner of problems. My wife was involved with a multi-million dollar class action lawsuit involving a similar product used in new home construction, (on the legal team.) several years back made by Shell and Celanese if memory serves. The latest generation may have fixed these problems, (or they may not have, I simply do not know.) but they will suffer under the reputation of their predecessors for a long time to come.

The failure mode was creep. The plastic would cold flow, relieving the clamping forces in the ferrule connection allowing the water to leak out.

Here in Houston Texas there are a couple of companies that offer a similar service called Ace Duraflo/ePipe for conventional tap water plumbing (many older homes here have galvanized ASTM A-106 pipe instead of PVC or Copper).

What they do is they open up the system and remove all valves and end connections and they connect hoses to all the outlets and they flow abrasive slurry through the plumbing to remove all the scale and rust, then they flush the slurry out and then flow epoxy through the plumbing to seal any pinhole leaks that may have been present.

Then they replace all the end connections with new valves and connections.

I've been told this is much cheaper and quicker than repiping.

This also sounds good!

If your pipes are just plugged and are structural sound and with no leaks, than the abrasive slurry and epoxy method should do the job. If they are corroding at the joints and have pin holes, than go for new piping. You don't want to pay out for the first option and then have pipe ruptures down the road. It is a tough choice either way. Pipe replacement is the 100% assured way to go.

There is a rust remover that is safe to use and works extremely well. When you are done with it, you can flush it down the sewer. It has an almost neutral ph of 5.5, and does not contain any hazardous or highly corrosive acids or distillates. It is organic and biodegradeable. It is also completely safe for iron, steel, copper, brass, aluminum.

It does not need to be recirculated, and will finish working in about 4 hours after being put into the system.

I experimented with this product before. I put a heavily rusted bolt into a container of the product. Within 1 hour the bolt was as clean as if you used a wire wheel on it. I spilled it on my hands, and it did not burn or cause any discomfort.

The company representative RIchard Greenwald can be reached at 216-401-1845.

There is a moybdate material that the same rep used to remove the non-rust debris from the system. It should probably be used first to remove the mud from the system.

I used it when I was a mechanical contractor. In a 20 story building, I used about 15 gallons of product to completely remove the mud from the building.

I used 5 gallons at a time, circulated it for a day, then drained the building. I removed 5 garbage cans full of mud.

Not only does it remove the mud, but it will protect the inside of the pipes from further oxidation, and will not interfere with other water treatments.

Once clean of mud, treat with the rust remover. Then recharge the system with the molybdate solution.

Oxalic acid dissolves rust, but may not work as well against items like CaCO3.

First check that you do not have pinholed sections or ones where the wall thickness has almost disappeared.

Then mix oxalic acid with dilute hydrochloric and let soak overnight. Flush and test, making sure the flush water doesn't dislodge rust into your equipment.

After you have cleared it enough, pressure test to see if you have now developed leaks, as in some sections the rust may be all that makes it leak tight!

Some sections will probably need replacement, but that would happen anyway.

Afterwards, of course, run the system with strainers to catch loose rust which will be coming adrift for some time and use inhibitors.

Depending on the condition of your pipe, this may save money or it may be more expensive than replacement.

Good luck.