@WaterFurnace: Thanks for checking on the history. It's a good sign that you are willing to check out problems customers have. As indicated by my previous posts, I am pleased with the performance of the system and a big fan of geothermal systems.
As with many appliance and home infrastructure products, only in the fullness of time is the picture complete. If the two units that have given me trouble don't act up for the next 5 to 10 years, I will be a happy camper.
@buckeyfarmer: The coil was indeed provided free of charge by WF. The labor cost was $500, the WF allowance was $200. There was also $88 worth of freon and as WF stated there is no allowance for that in the WF warranty.
The other unit which was low enough on freon that it wouldn't run cost $306 to fill. One good thing about the WF design is it was smart enough to know it was low and not run. Older, simpler heat pumps I've had would have kept going and done damage to the unit.
There is a continuing problem in all aspects of our technologically complex world that there can be cost associated with diagnosing a problem. With the shift from servicing equipment at a part level to a subsystem level, and the increased cost of labor the days of trying a $5 part and $15 in labor are gone. It is $250 to have someone come down the driveway, and the replaceable subsystems are in the $50 and up range. The R410A refrigerant is a good deal from an environmental point of view, but it is pricey. Once again, only the fullness of time will tell if I just had a bad bounce and had some maintenance cost earlier in the cycle than normal. Total cost of ownership over a 10 year period will tell the story.
The one suggestions I'd make the WF regarding their warranty might be a policy where if you add freon to a unit, and within (say) 6 months you have to replace a part that was causing the leak, that the cost of adding the freon be refunded since that service call was a symptom of a problem that was diagnosed later. Any unit that leaks down in 6 months has a problem. The freon fill was a diagnostic step in determining that problem. Any assistance given to alleviate the shared cost of diagnosing the problem born by the customer would no doubt be appreciated.
Pete