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GordCooper 03-13-2012 12:02 PM

A strange one - polybutelene piping used in radiant heating system
 
Hey guys,

I've been having some issues with my radiant heating system lately, and I had a guy take a look at the issue (one of the pumps was grinding away). Well, when he took a look at the system, his first instinct was 'Your system uses polybutelene, so a band-aid would be to replace the pumps, but the real solution is to teardown and replace the entire system, get some baseboard heating in, etc...'

The pump replacements run in the neighbourhood of $700-$800, and he stated that they could last anywhere from a couple years to a couple hours, whereas the system teardown is in the area of $15-16,000, so there is obviously a large gulf of difference here.

Now, I've taken a look at some information on polybutlene online, and I've found a few things -

For the most part, the big polybutelene issues ran in system installed between the late 70's, and late 80's. Our system was built, with the house, in ~1994.

Additionally, the majority of issues with this piping were recorded in the United States, not in Canada. Again, we live in Canada with this system, in British Columbia.

I know that a couple years ago (before we bought), the system was flushed, and a pump replaced, with some rust cleaned out of the boiler. This is apparently the main issue, that the polybutelene piping oxygenates the water, thus allowing rust into the system at different levels.

My question is this - is there a solution that could be used, like conditioning the lines, etc... that could help to alleviate this issue? Basically, there is a pump grinding away, and the pro stated that it's because it's backed up with rust (using his experience and viewing a video of the occurence), and I'm just a little leary of this grandiose solution to this issue, if you can understand.

Thanks so much in advance!

Gord

joecaption 03-13-2012 01:04 PM

It's a closed system so how does he think oxagen is getting in to cause the rust?
Most of those pumps are simple enough to just pull apart and replace the seals and bearings for far less money then a new pump.

Alan 03-13-2012 10:17 PM

Quote:

Originally Posted by joecaption (Post 876731)
It's a closed system so how does he think oxagen is getting in to cause the rust?
Most of those pumps are simple enough to just pull apart and replace the seals and bearings for far less money then a new pump.

From what I understand the plastic tubing used for radiant floor these days has an oxygen barrier. I did a little study on it in apprenticeship training, but I can't remember the scientific term for why the oxygen goes through the plastic but water won't come out.

It does though. They compare it to a balloon filled with helium.


Does the system have an air removal valve on it? They have a few different terminologies. It's probably up high in the room with the pump and you might even notice it drip occasionally.

For the record i'm not a radiant floor technician nor have I installed one, but i've done a fair amount of reading on the subject over the past 5 years, so I get some of the basics.

burnt03 03-13-2012 10:21 PM

I'm in BC too, work for the town water department.

I haven't seen a ton of poly-B failures, but the ones I have were almost exclusively on the hot water side. From what my partner tells me (water guy for about 25-30 years), the chlorine in the water reacts with the tubing and breaks it down, with the hot water accelerates the chemical reaction.

So, assuming it's not chlorinated water within your heating system, you're probably ok to leave it.

jaydevries 03-13-2012 11:09 PM

here is a link that talks about why oxygen barrier pipe is needed
http://www.pexuniverse.com/content/p...vs-non-barrier

i have heard of people who empty and refill their boiler systems up every year with new rain water to help make system to work longer due to less iron and salt content
if it was me i would switch to oxygen barrier pex and run it myself it is a pain to use since the pipe is so stiff if using the aluminum style


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