Polybutylene pipes used for hydronic heating system

eugekhan

Hello - I'm looking to buy a house with polybutylene pipes. My inspector mentioned in his report that the hydronic heating system uses polybutylene plastic plumbing supply lines. Please see excerpt from his inspection below.

"Polybutylene plastic plumbing supply lines (PB 2110) are installed in the subject house and used in the hydronic heating system. (Picture 1 thru 4) Polybutylene has been used in this area for many years, but has had a higher than normal failure rate, and is no longer being widely used. Copper and Brass fittings used in later years have apparently reduced the failure rate. Unable to verify fitting material used as the pipes are under the floor."

I wanted to find out #1, how severe of an issue this is and #2, what kind of remedies/solutions we could undertake to mitigate this issue.

Thank you!
Eugene

Zman

Do you know which Poly you have? Is it red or grey? Are there any markings? Do you have pictures of the the tubing or fittings.

It is pretty unlikely that there are fittings buried under the slab.
The grey poly did not have an oxygen barrier which brings about separate issues.

eugekhan

Thanks @Zman

It is Light grey color and has PB 2110 marking on it. The house was built in 1990.

Is this a deal breaker? The house is around 5000 SF so it seems catestrophic if we would need to replace all the piping

eugekhan

Here are a couple photos of the PB piping

JUGHNE

I have about 2000' +/- of red O2 PB buried in concrete floors since 1995, in my house.

The only issue was the connections at the Infloor pump manifold. Spliced on to the tails with PEX and new manifold.
The mixing valves work on 2 out of 3 units.
Still have original pumps running.
FWIW.

hot_rod

Looks like it has been worked on already, some Pex splices.

The tube really was not the main problem with the failures, it was the crimp rings, acetyl fittings and some brass that dezincified.

However if it is a non barrier tube, oxygen gets into the system and will speed the corrosion of any ferrous metal in the piping.

What type of boiler? A water sample from the boiler would maybe tell how much corrosion is going on.

If the system heats well, and no leaks in the tube or manifold the system could be upgraded with a heat exchange between a ferrous, cast iron boiler and the tube. Stainless circulators and special expansion tank.

Zman

It's a tough call. As Hot rod mentioned, you will need to isolate all ferrous metals if it has not been done already.

I would be comfortable that the tubing running at low radiant temps will last for many more years. There really were no major failures of the tubing itself in closed loop heat systems.

What always scares me is the perception that future buyers may have. You may live in the house for 10 years and have no issues at all. When you go to sell it you will run into inspectors and buyers who are in the same shoes you are in today.

ggrider

I am trying to net out if I got lucky and how with my PB in floor heating system.
I have found a lot of very nice posts on heatinghelp and elsewhere that cover most aspects of what i am trying to confirm about why my system has functioned nearly flawlessly (a new expansion tank every 7 years or so).

My system uses red O2 barrier PB (yes there were products on the market in the mid 90's before PEX was a completely proven tech apparently) buried in gyp-crete. It is a sealed system with what looks like copper manifolds with copper to the valves/boiler that are in closet walls with access panels. The makeup valve has a nice feature that it will shut off if the pressure drops and it has an expansion tank of course.

Here is what I think i have learned and am looking for confirmation:
- I got lucky with the O2 barrier version of PB so O2 doesn't enter the system and corrode the boiler or other parts and I dont have to find special parts that wont corrode or use oxygen inhibitor chemicals in the system.
- While prolonged exposure to high chlorine makes PB brittle, since this is a closed system the amount of chlorine the tubing is exposed to is tiny, so the use case for the us of O2 barrier PB was well chosen where chlorine exposure is extremely low
- its a relatively low pressure and low temperature system which further mitigates tubing expansion and means then entire system is perhaps a bit over-engineered
- All but the ends of the tubing is encased in gyp-crete so expansion over time of the tubing is mitigated and the ends that are not in the gyp-crete are easily accessible and inspect-able as are the manifolds and crimps etc. which all look like new after decades of use.
- Copper is used throughout the home including supply/return for the radiant manifolds.
- The makeup valve protects to a great extent against catastrophic leak issues as it will stop refilling if a large leak occurs.
- Good maintenance checking of the makeup valve, boiler condition, and expansion tank has helped the system remain rock solid.

While the system is PB, it seems as if it is based on a solid use case with the right features to continue to perform well. I can see there are many posts that describe how PB can be used incorrectly with horrible results.

Have I interpreted the many posts I have read and come to a reasonable conclusion as to the reason the system has been so reliable and my expectation it should continue to be reliable?

Thanks
Gary Grider

HomerJSmith

I'm agin' it, of course, I'm agin' almost everything. Why? Because there are more people trying to fool me, than giving me the straight dope.

As I recollect, Shell came out with this product. A contractor acquaintance, who was on "60 Minutes", ya that "60 Minutes" relaying his experience with this product and not revealing a sizable award in a law suit told me that when he started having leaking problems in a sizeable multi-unit complex that he plumbed for domestic water, the rep told him it was the fitting that failed and that he had to use new and improved fittings and by the way buy the installation tool for $300.

Having done that, at much expense, I might add, the connections leaked again. He re-did the whole thing in copper.

The problem wasn't the fittings, but the connection to the fittings. No matter where you put the 'spliced in fittings', it failed, Bad tubing.

Reminds me of the ABS fiasco where the leaks developed at the ABS fittings because of faulty resin in the pipe and resulted in a major law suit.

I have come across several installations of this piping in radiant floor sys and the only problems that I saw was 02 ingress and the resulting damage.

https://moderncastle.com/polybutylene-pipes/

https://www.oklahoman.com/article/5587031/polybutylene-piping-pokes-up-in-new-class-action-lawsuit

Larry Weingarten

Hi @ggrider , I'm not a fan of PB, but think I remember that it was banned in the US, not Europe. In Europe they are far more cautious about the use of any chemicals in the water than we are here. So I found this link about its use in over there: https://www.pbpsa.com/why-pb-1

Yours, Larry

Zman

@ggrider I think you understand your situation perfectly.

solradman

I'm looking at doing a manifold and plump replacement for one of the "infloor' systems with the ploy pipe. Anyone know what splice works best, the tubing is 1/2" OD?

Zman

Something like this works well https://www.amazon.com/Watts-LFP-505-Polybutylene-Transition-Coupling/dp/B003KVZ5PG

JUGHNE

Is your PB 1/2" OD and 3/8" ID?

solradman

Do not know the inside ID. I do remember that the tubing walls are thin (1/16") sounds right.