Polybutylene / Copper question

[RoyalFlusher]

I am re-plumbing my house to replace the PB time bomb in my walls with PEX. I came across something puzzling and wonder if anyone can shed some light.

The PB from the supply enters through the slab then tees off to the water heater. The PB goes about halfway up the wall then transitions to copper. It exits the wall and about a foot later transitions back to PB. Same setup on the hot side - PB out of the WH, change to copper into the wall and halfway down then back to PB.

I cannot figure out why anyone would do this. Is there possibly a code issue here? Or, could it be just some guy who was short of poly but had some spare copper?(!)

My plan was to just run all PEX.

Any thoughts or help appreciated.

Thanx.

 

[hj]

Screw up. Probably heard you have to have at least 18" of copper to the water heater and must have thought it could be any where above the heater.

 

[Sponsor]

 

[Jeff H Young]

unless code changed do not run pex to water heater there is a minimum not sure how far away at moment certainly not less than a foot and it could be 18 inches away