coalboy wrote:I plan on useing pex when plumbing my coal boiler in a series with my oil boiler. Would 1in diameter be big enough or should i go larger. thanks Coalboy
Pex al pex and regular pex are manufactured to different standards. 1" Pex al pex has approximately the same inside diameter as 1.25' diameter pex.
The (inside) diameter you need is a function of the amount of heat to be transported, the length of the loop, and the design temperature drop. The size of the pump you use can also make a difference.
As a rough rule of thumb for a typical home installation--with perhaps 100,000 BTU per hour net output, and a loop length of less than 300 feet 1" Pex al pex should work fine. If you have doubts about your installation it is worthwile to do a more detailed calculation.