propylene glycol in an oil fired boiler system

coalkirk · Post by **coalkirk** » Fri. Apr. 06, 2018 7:08 am

Here's a few pics. This is not food grade PC. The engineer wasn't there. I got this info from his realtor who said the engineer read somewhere that this was a good idea. His purpose was to "prevent corrosion" in the system. Of course in a closed system there would be no corrosion. The really concerning part to me is the lack of a backflow preventer which would allow the PC to leak back into the potable water system.

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McGiever · Post by **McGiever** » Fri. Apr. 06, 2018 8:59 am

Oh, there are added inhibitors...

Post by **StokerDon** » Fri. Apr. 06, 2018 9:33 am

Unless the house goes below freezing periodically, that sounds like a terrible idea. Especially with no back flow preventer. Any time you loose house water pressure, glycol could go right into the house potable water. Really not good!

-Don

lsayre · Post by **lsayre** » Fri. Apr. 06, 2018 10:29 am

You should be able to purchase food grade propylene glycol at RV supply stores. It is used to winterize RV's.

scalabro · Post by **scalabro** » Fri. Apr. 06, 2018 10:49 am

Why is a hot water heating system connected to the potable supply?

hotblast1357 · Post by **hotblast1357** » Fri. Apr. 06, 2018 11:02 am

scalabro wrote: ↑
Fri. Apr. 06, 2018 10:49 am
Why is a hot water heating system connected to the potable supply?

That’s how u fill it..

coalkirk · Post by **coalkirk** » Fri. Apr. 06, 2018 11:16 am

hotblast1357 wrote: ↑
Fri. Apr. 06, 2018 11:02 am
That’s how u fill it..

Yes. Look at the photo I posted of the plumbing. Between the shut off valve and the pressure reducing valve there should be a backflow preventer.

rberq · Post by **rberq** » Fri. Apr. 06, 2018 11:46 am

scalabro wrote: ↑
Fri. Apr. 06, 2018 10:49 am
Why is a hot water heating system connected to the potable supply?

Ready-made pressurized water for filling or replenishing the system. If I'm not mistaken, there's a valve that automatically bleeds air and lets more water in if needed???

To put in glycol or glycol/water mix, special equipment is needed to pump it in.

VigIIPeaBurner · Post by **VigIIPeaBurner** » Fri. Apr. 06, 2018 11:47 am

hotblast1357 wrote: ↑
Fri. Apr. 06, 2018 6:20 am
Well it’s a good thing we drink our boiler water! Lol

It's been done! The place I worked at had Kosher certification for our products. A Rabbi would visit and inspect everything in the plant including the 600 HP boilers. Everything that came in contact with the products had to be Kosher. Since boiler steam was part of our process ... well you get the idea! We never saw him again

lsayre · Post by **lsayre** » Fri. Apr. 06, 2018 12:52 pm

scalabro wrote: ↑
Fri. Apr. 06, 2018 10:49 am
Why is a hot water heating system connected to the potable supply?

As far as I can tell they all are. They need to be up to code though. The boiler side is only at 10-15 PSI, and the water supply side is at 35-60 PSI.

scalabro · Post by **scalabro** » Fri. Apr. 06, 2018 2:29 pm

Why not use an header/expansion tank with a pressurized cap, like an automotive setup? This way it’s stand alone. You could use coolant like “Evans coolant” and never have a corrosion issue. And, since does not boil at low temps you could utilize very high coolant temps with little to no system pressure.

lsayre · Post by **lsayre** » Fri. Apr. 06, 2018 2:40 pm

scalabro wrote: ↑
Fri. Apr. 06, 2018 2:29 pm
Why not use an header/expansion tank with a pressurized cap, like an automotive setup? This way it’s stand alone. You could use coolant like “Evans coolant” and never have a corrosion issue. And, since does not boil at low temps you could utilize very high coolant temps with little to no system pressure.

It certainly seems like it could be done, but it might not meet code. ???

coalkirk · Post by **coalkirk** » Fri. Apr. 06, 2018 3:49 pm

It's simple enough (and code required) to install a backflow valve then it is isolated.

Post by **StokerDon** » Fri. Apr. 06, 2018 6:45 pm

scalabro wrote: ↑
Fri. Apr. 06, 2018 2:29 pm
Why not use an header/expansion tank with a pressurized cap, like an automotive setup? This way it’s stand alone. You could use coolant like “Evans coolant” and never have a corrosion issue. And, since does not boil at low temps you could utilize very high coolant temps with little to no system pressure.

No need to do that. The point is, in a closed hydronic system, there is no corrosion problem. Why this guy thought it would be a good idea to put glycol in there is the problem. He probably just got some bad advise.

-Don

hotblast1357 · Post by **hotblast1357** » Fri. Apr. 06, 2018 6:49 pm

Many people do it for the freeze protection.