I came to figure out a leak, and diagnose the system. There were 6 zones here originally. Zone 2 is actually 2 zones tied together in the field, and zone 4’s valve has been eliminated. However part of zone 4 has been piped into zone 5. There are only 4 zones here now. Today, I repaired the leak by replacing the zone valve for zone 1 (passing water). This solved the leak. I also replaced a 4” head on zone 5. I checked my work, and spoke with the customer.