Edwin Pawlowski wrote:
First step is to turn off the water. Second step is to open a water valve
to let off the pressure. Now it will come off easily. Put a little
Vaseline or white grease on the gasket to help it come off the next time.

It is very important to relieve the pressure. Just like opening a jar of
pickles, if you break the seal, it turns easily. If not, you can actually
damage the housing.

Edwin -
Thanks very much. I have relieved the pressure by pushing the red
pressure release button on top. Do I need to do more? It doesn't budge
at all.