A Danfoss PM-1 is the slave section: If this is being used as a regulator, there is a pilot module threaded into the adapter that looks like the top of a Theremal Expansion Valve without a Capillary Tube. If its a gas powered valve, it has a custom reducing coupling inserted in the same adapter boss which extends as pipe or tubing to a pilot solenoid. Either way, the valve should open at least part way by means of the manual opening stem in the center of the adpater.

If you don't have an upstream service valve, you will need to pump out the evaporator. To advise how to do that you will need to provide us some detail on the valving, and whether this is a Hot Gas Defrost arrangement or some alternate form of defrost.