Your solder should always be placed on the opposite side of the pipe where the flame is directed.…
An Uponor plumbing system features Engel-method crosslinked polyethylene (PEX) tubing. This is a flexible plastic tubing product that has been used for more than 35 years in radiant floor heating, plumbing and fire safety systems.
Uponor Controls and Poly pipe cladding on boiler copper lines
Chimney systems by code need to be installed once a transition through a combustible (roof or wall) is required. Once the transition to chimney is made the chimney system must be completed through to termination (chimney cap).
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The gray water line is Polybutylene (Poly-B for short) and is no longer manufactured. The product line was discontinued due to the potential for breakdown given certain chlorine levels in the water and a particular kind of fitting, both of which were not an issue in Canada. These pipes, given they are correctly installed, will most likely outlive the house here in Canada and should not be a cause for concern. Poly-B has given way to a number of different waterline manufacturers, the most common one being Crosslinked Polyethylene, better known as Pex, used extensively as a substitute for more expensive plumbing systems such as copper.
See the following link for more info:http://www.pexinfo.com/