A Manual Air Vent
The cap on automatic air vents must not be fully tightened. It is there only to
prevent the entry of dust which would clog the mechanism. The vent must be
The air vent should be constructed of metal. Plastic air vents are not recommended
because catastrophic failure is common. If a plastic vent is found, make a note on
the inspection worksheet and schedule the vent for replacement.
Check sensor wires for ultraviolet (UV) degradation. They should be secure and
make a watertight connection where they pass through the roof. They should not be
near sharp edges, or line voltage wiring or loads. Avoid sharp bends.
Make sure the connection to the sensor is still electrically sound and the connectors
The sensor wires must not be in contact with collector loop piping. They may be
fastened to the outside of pipe insulation, and can be under the insulation jacket.
They must never be between the insulation and the piping, or damage will result.
The thermistor sensor used for measuring the actual collector temperature by the
differential thermostat must be securely mounted to the absorber plate, or the
collector outlet piping. It must be in good thermal contact with the absorber or outlet
3.1 INSPECTION PROCEDURES