This sucks because my first call is at a house with a ground source pool heater tomarrow. I've serviced this home a couple of times. They have money and are the type.
Last service I added a bunch of water to the ground loop. Brought the pressure up to around 75 psi. I didn't know it had a 12 pound expansion tank. The guy was pissed. Thought I screwed up his loop. Called the boss and boss agreed that the loop should never need water added. This is different that what I learned over the years at another company and factory training from WaterFurnace.
Okay done crying.