Need Help Identifying Winterizing Parts


May 2, 2020
New guy here looking for help identifying the parts left behind by the pool company that winterized my pool. I inherited the pool for the last 6 weeks of the 2019 season so this is my first open.

I have the pump drain plugs, filter drain cap, and sight glass figured out. There’s this odd shaped green piece that I have no idea where it belongs. Any ideas?

When turning the equipment on, any specific order of operations other than priming the pump, and waiting to turn the heater on until everything has been running for a bit?