A:  You can easily convert from PEX A to Pex B by just using a PEX B insert fitting.  Here is a description of how to do that along with a couple other methods: https://www.willplumb.com/how-to-connect-pex-a-to-pex-b/

A:  We have three fittings that would join the pipe. A PEX-B brass or poly alloy 1/2 in. coupling, or a Tectite push-to-connect 1/2 in. coupling. Those items are: 1/2 in. Brass PEX Barb Coupling - Model #APXC1212, Store SKU #259713, Store SO SKU #1002404976, Internet #301541094 1/2 in. Plastic PEX Barb Coupling (5-Pack) - Model #PXPAC125PK, Store SKU #1001404687, Store SO SKU #1002404967, Internet #301541085 1/2 in. Brass Push-to-Connect Coupling - Model #FSBC12, Store SKU #1002429570, Internet #301410237

A:  Apollo makes a coupling to go from Pex A to Pex B. You can find it on line or at any Home Depot store. Good luck with you’re project. 

A:  Yes there is a coupler for pex A to pex B. Or otherwise known as crimp to expansion.

A:  The best option would be an male or female adapter depending on the thread of the "old steel pipe". Which PEX piping system you desire to transition to would also be important information. Here is an example of a female adapter for PEX-b (legacy type PEX that requires crimps or clamps to secure): part # APXFA1212. For transition to PEX-a or Expansion PEX, the part # would be EPXFA1212. Enter either of these part numbers into the search bar on homedepot.com and the result should appear. Should you have any additional questions that we could answer, please contact us @ 1.888.229.2874 and we will be glad to assist you. Good luck with your project!

A:  When making a PEX-A connection, you'll first need to slide the PEX-A Expansion Sleeve onto the PEX-A pipe. Then, using your manual or power tool, expand the pipe and sleeve enough so that you can slide your fitting into the pipe. After about 30 seconds, the pipe and sleeve will find its original form and compress back down onto the fitting, making a successful connection. After doing so, it is not uncommon for you to be able to twist the fitting 360°. This will not cause a leak. Do not use super glue on or with PEX.

A:  Expansion tool to stretch it and then it will compress.