57
PURGING AND FLUSHING THE SOLAR COLLECTORS
Upon completion of the installation, if the service 3-way valve was not opened during the tank filling procedure,
then it is necessary to purge the air from the collector circuit.
Other than at the time
of the water heater’s installation, it will be necessary to purge air from the collector
circuit:
•
When the water heater is to be turned on and the solar collectors and solar hot and solar cold pipes have
been drained.
•
After maintenance has been conducted on the pipe work and air has entered the system.
•
If the circulator appears not to be circulating water around the system.
It is also recommended to flush the solar collectors every five (5) years. This will assist in keeping the solar
collectors, and solar hot and solar cold pipes clear of sediment.
It may also be necessary to flush the solar collectors if there is sediment in the water supply.
Warning:
Other than at the time of
the water heater’s installation, it is recommended purging air from the
collector circuit or flushing of the solar collectors be conducted early in the morning, within three (3) hours of
sunrise, when the sun is low in the sky. The water temperature inside the solar collectors is lower as the solar
collectors would not have had a chance to gain as much heat as later in the day. Purging air from the collector
circuit or flushing the solar collectors at a time later than this can result in the discharge of high temperature
water and in some circumstances, high temperature steam.
To purge air from the collector circuit or flush the solar collectors:
•
Open a hot water tap and allow the water to run for five (5) minutes.
•
Close the hot tap.
•
Wait a further five (5) minutes before attempting to purge air from the collector circuit or flush the solar
collectors.
This will assist in the transfer of any high temperature water in the solar collectors to the solar storage
tank.
Warning:
Exercise care, as water discharged from the solar collectors may be of a very high
temperature.
•
Follow the procedure
“Bleeding the Solar Collectors”
on page 53, allowing the water to flow from the
service valve drain line for a few minutes before closing the service valve.
