Potable PEX in a Hydronic Herating System

"Is the customers' new steel boiler in danger of premature failure?"

Yes.

Drawbacks of PEX pipe.

Hi doorman. Yes, I saw the Wikipedia on this subject too. I especially liked the part where the author asserts: "..... in new installations PEX pipes and iron-based components are not intermixed....". That blanket statement is simply untrue. Boilers continue to made from ferrous metal and PEX continues to be used in concert.

My son works for a Natural Gas Utility which supplied and installed thousands of boilers having an aluminum body, and they have documented early failures where the feedwater was oxygen-rich. My brother deals with industrial boilers and advises that it is standard procedure to 'treat' feedwater - to minimize corrosion.

My second question addressed that point.

There is a type of PEX that has an oxygen-barrier. It is called PEX-Al-PEX which has PEX on both sides of a thin aluminum layer. The Aluminum provides the oxygen barrier. It is less flexible due to the aluminum and tends to keep its shape after being bent.

The link that Doorman inserted actually had a lot of positive things to say about PEX. Perhaps the original PEX installer didn't realize there was a difference. He probably got the job as the low bidder. Frequently the winners of construction contracts look to cut costs where ever they can find cheaper materials. Not a long term strategy by any means.

Hi NUOJoe.

I am familiar with the oxy-barrier PEX and have used it. The owner provided this material and probably thought that 'potable' rating conferred the highest standard, so on the principle of "nothing but the best" for this project, he sent in a material that will eat the guts out of his brand new German boiler in about 6 years. The plumber sent in to do the work was a jobber, not a contractor, and he ran through the materials provided without apparent comment, and flew out.

The boiler specialist (not me) and I have just flown-in and we each noted the 'potable-rated' PEX incorporated in the heating loops.

There is no mileage in it for us telling the owner his idea is a bad one.

What we are looking for is a device that we can add to the hydronic system which can maintain a level of sodium sulfite in the circulating mix of water/propylene glycol. My web search shows it to be more of a practice in industrial boilers, where an engineering staff perform monitoring functions. When we leave this place there will be only a chef, some guides and fishermen left - no engineering staff.

We need an automated monitoring/dispensing device. Does anyone know of one they can recommend?

I think you need to sell the idea and get a contract for an annual system checkup.

Check antifreeze, circulating pumps, expansion chamber, record temperatures and pressures, check for gas leaks, water leaks, etc.

This could be an opportunity, not a problem!

We'll probably be doing that for the Solar installation anyhow, so why not?

This is definitely a GA!