pex as a piping option for secondary loop?

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kuribo

Feeling the Heat
Dec 10, 2007
388
SW WI
Getting ready to put my radiant heating system together and plan to use a primary/secondary loop configuration. I will have 6 or so sets of closely spaced tees on the secondary loop and am wondering if using pex for the secondary loop is a reasonable choice. Size is 1.5 inches and at that size, it seems I wouldn't save too much money using black iron (but would save a lot of time and effort) and copper would be much more expensive with lots of sweating....Anyone use an all pex plumbed system? Any concerns with this approach?
 
Getting ready to put my radiant heating system together and plan to use a primary/secondary loop configuration. I will have 6 or so sets of closely spaced tees on the secondary loop and am wondering if using pex for the secondary loop is a reasonable choice. Size is 1.5 inches and at that size, it seems I wouldn't save too much money using black iron (but would save a lot of time and effort) and copper would be much more expensive with lots of sweating....Anyone use an all pex plumbed system? Any concerns with this approach?
I used 1 1/4" pex for the runs to buildings (3) and hooked them up to a 2" black manifold supply and return. I have had no problems with the setup. Foamit UP
 
The near boiler piping should be hard pipe and pex is fine after that. Be sure to use oxygen barrior if doing a closed system.
 
I plan to use hard pipe at the boiler and then transition to pex to the house. This is the primary loop. Inside the house I will have my storage tanks and radiant zones. If you look at the diagrams for a primary-secondary system, the secondary is a loop with closely spaced tees coming off it that feed the supply and return from the zones. I am asking about this secondary loop. Has anyone plumbed their secondary with pex instead of iron or copper?
 
I plan to use hard pipe at the boiler and then transition to pex to the house. This is the primary loop. Inside the house I will have my storage tanks and radiant zones. If you look at the diagrams for a primary-secondary system, the secondary is a loop with closely spaced tees coming off it that feed the supply and return from the zones. I am asking about this secondary loop. Has anyone plumbed their secondary with pex instead of iron or copper?


Sure, look at the manufacturers charts for flow rates, pex is a bit smaller ID then copper, and the insert fitting add additional pressure drop.
 
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