Quote Originally Posted by scarry View Post
Fixed oriface expansion device, which slides like some check valves, used on reverse cycle AC units.

On cooling the accuraters at the Evap,slide one way, and are the expansion device, where the ones at the outlet of the condenser slide the other way for no expansion, full liquid flow.

On heating the opposite happens, they slide the other way, at the Evap they let liquid through, no expansion, at condenser,slide and become the system expansion device.

They have strainers in them that clog up, often we pull the strainers out and they still clog up.
Even with a large Bi flow liquid line drier, they still seem to clog up, with Carbon looking stuff, and sometimes metal pieces.
Thanks very much, Paul. I found the following that shows a drawing of one. I just could not understand what they were trying to achieve until you mentioned reverse cycle systems.

e740c047-b172-43a1-a88b-ad136c97ecd7.pdf (manualsonline.com)