12
BLEEDING THE SOLAR COLLECTORS
It is 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.
Warning:
It is important bleeding of the collector circuit be conducted early in the morning, within three
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. Bleeding the
collector circuit 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:
Ensure the water heater is full of water and all of the hot
taps are turned off.
Using a flat blade screwdriver, open the bleed valve (if it
is not already open) fitted adjacent to the solar hot water
(from collector) inlet of the solar storage tank (see
diagram).
The mains pressure will force water to flow from the tank
and through the pipe work, expelling air from the
collector circuit through the bleed valve. This is
evidenced by spurting of water from the drain line
connected to the bleed valve.
Warning:
Stand well aside of the air bleed valve
drain pipe discharge point and exercise care to avoid any
splashing of water, as water or in some circumstances
steam discharged from the solar collectors may be of a
very high temperature.
Close the bleed valve when water runs freely from the
drain line.
TO TURN OFF THE WATER HEATER
If you plan to be away from home for a few nights, we suggest you leave the water heater switched on.
If it is necessary to turn off the water heater:
Switch off the electrical supply at the isolating switch to the solar storage tank.
Switch off the electrical supply at the power outlet to the solar control unit (refer to note below).
Close the cold water isolation valve at the inlet to the water heater.
Notes:
The freeze protection system will be rendered inoperable if electrical power is not available at the solar
control unit. Damage caused by freezing due to no power at the solar control unit is not covered by the
Solahart warranty. Refer to
“Terms of the Solahart Warranty”
on page 53.
If there is a risk of freezing, the electrical supply to the solar control unit should not be switched off
unless the solar collectors and solar flow and return pipe work are drained, otherwise damage could
result (refer to
on page 10).
AIR BLEED VALVE & SOLAR
NON RETURN VALVE ASSEMBLY
Solar Pumped Open Circuit
