Originally Posted by 907plumber
whats the difference between an open boiler system and a closed? Or what is the definition of each?
I was looking at another thread that was talking about aqua pex being used for a closed system boiler (how that was a no-no) but would be okay for an open system
An open system is open to the atmosphere. Like an out door wood boiler also a HWT is considered open sytem.
A closed system is like an indoor boiler with a boiler feed that is pressurized to the pressure you need to rise the water to the given height you need ( top floor )
On a closed system you are able to use black pipe or cast Iron boiler or steel. Any oxgen getting in to the system ( usually by adding new water )
will corrode the pipe, pumps, boiler.
Hepex has an oxgen barrier which limits the amount of oxgen that can enter the pipe from the atmosphere. Aqua Pex has no barrier.
Hope that helped to answer your question