Hot water zone on steam boiler

RichardBaran

We are doing a steam boiler changeout and adding a hot water zone. We have decided against using a heat exchanger - basically following the directions in the Tech Tips and/or Dan's How come book(Condensate Hot-Water Heating.)
Here is my question - has anyone done this using pex to supply the hot water radiation. Obviously the near boiler and bypass piping will be black pipe.
Any concerns about the temperature limits on pex or use of the pex compression fittings?
Your thoughts and/or experiences are appreciated.
Rich

Joel_3

pex

Iwould be very concerned due to the high temps you typically get out of that situation. Pex will really expand when it is that hot. i probably would go copper unless I just couldn't get it in there or something Then I'd choose fosta pex (pex al pex). But I'd really try to stay copper. IMHO the way to go.

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Al_3

you would most likely have to put an aquastat on it anyway, why not add a relay {SPDT}& not let the hot water loop run when the steam t-stat is calling?

RichardBaran

check out How Come

Thanks Al, but - if you check out Dan's book How Come - the chapter on condensate heating; you can control the temperature in the hot water loop with a simple bypass piping - I know I have to stay below the max temp on pex - I was hoping someone on the wall had done it with pex. I can do it with copper, but pex would be so much easier.

Mad Dog

I've done radiant off of a steam boiler using......

Pex, but.......it goes through through a three way mixing valve first, before it goes through the pex. Mad Dog

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