Proper tilt angle for purpose. Receive reasonably unobstructed sunlight or surface area has been increased accordingly. Collectors and roof are ice and snow protected. Space is available for inspection and service. Weep holes are properly located.
Collectors are rodent protected.
Water-flow to and from gutters is unobstructed. Glazing is not cracked. Freeze sensor is well protected and secured. Mounting hardware is well protected. Dissimilar metals do not touch.