auxiliary components information

Hi Forum Users,
I am looking for websites provide full information about the AC or refrigeration auxiliary components such as oil separator, oil pressure gauge, solenoid valve, defroster, and check valve. The full information involves the component trouble shooting, how to be installed and selected. Any help or advice will be greatly appreciated. :)

This thread is also entitled to be sticky.
Please have a look at www.sporlan.com

Thank you so much for wonderful link.