Stick Home Geothermal ques?

You will need a service or operating manual to muck about with a geothermal heating system. Keeping it in the hands of a service technician may be a better option.

The port may be establish full loop fluid, an auxiliary port for a water heater, or for another intrinsic function.

Without knowing where the port is in relation to the flow and what appliance you have, no one should just guess at this.

I'd suggest you call the service that was just there. They did leave a tag or label w/phone number, no?

dr you win

How is this RV related?