I take it that you are swapping the water inlet from a Carver Compact (with the two swivel pins to secure the pump) to a Truma Ultraflow water inlet (with a trigger connection). If this is the case then it's a simple job because it just means disconnecting the water pipe from the rear of water inlet (after draining the water system) and disconnecting the two wires that go to the pressure switch. Unscrew the old water inlet via the four screws then carefully prize the housing away. Clean the old mastic off thoroughly then apply fresh sealant to the new inlet and screw it back on using the existing screw holes. Re-attach the water pipe and the two wires and that's the job finished. Re-fill the water system and check for any water leaks.
I changed our water inlet to the Truma one about a year and half ago on our pennine pathfinder. the job was really straight forward and didn't require any changes to the campers body panel. I did need to add an additional none return valve in the pipe as advised by the Truma installation instructions
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