Table of Contents
Advertisement
DRAINING AND FLUSHING THE SOLAR STORAGE TANK
DRAINING AND FLUSHING THE SOLAR STORAGE TANK AND COLLECTORS
It may be necessary to drain or flush the solar storage tank of an open or closed circuit system or the solar
collectors of an open circuit system during maintenance or if there is sediment in the water supply. This should
be conducted in the morning, within three (3) hours of sunrise when the sun is low in the sky. The water or
closed circuit fluid temperature inside the solar collectors should be lower as the solar collectors would not
have had as much chance to gain as much heat as later in the day.
Warning: Exercise care to avoid splashing of water, as water discharged from the solar storage tank and
solar collectors may be of a very high temperature.
Note: The water discharged from the solar storage tank and solar collectors may contain sediments and should
be diverted away from any section of roof which is part of a rainwater collection system.
Prior to draining and / or flushing the solar storage tank and / or solar collectors:
Open and Closed circuit system
Cover the solar collectors with an opaque material to prevent absorption of solar energy and the transfer
1.
of heat to the solar storage tank. If fitted, cover the OTP valve with a cloth soaked in cold water.
Failure to cover the solar collectors may cause a safety issue.
Open a hot water tap and allow the water to run for five minutes immediately prior to draining or flushing
2.
the solar storage tank and / or solar collectors.
This will assist in the transfer of any high temperature water in the solar collectors to the solar storage
tank of an open circuit system or heat from high temperature closed circuit fluid in the heat exchanger and
solar collectors to the water in the solar storage tank of a closed circuit system.
Close the hot water tap.
3.
Turn off the water heater. Refer to
4.
5.
Ensure all hot water taps are closed.
Closed circuit system
6.
Attach a hose to the valve drain port of the fill drain valve assembly.
Place the end of the hose into a container.
Place an absorbent cloth on the roof under the fill drain valve assembly prior to loosening the screw. This
will assist in catching any spilt closed circuit fluid.
Loosen (but do not remove) the valve screw on the fill drain valve assembly a few turns to open the valve
7.
drain port.
This will release the pressure in the closed circuit.
8.
When the pressure is relieved, tighten the valve screw on the fill drain valve assembly.
9.
Very carefully, remove the retaining clip securing the closed circuit relief valve on the right hand side of
the solar storage tank and remove the relief valve.
Note: It is important the closed circuit is not pressurised whilst the storage tank is unpressurised.
Warning: Relieved air or closed circuit fluid may be hot.
Open and Closed circuit system
Operate the temperature pressure relief valve lever - do not let the lever snap back or you will damage
10.
the valve seat. It is very important the lever is raised and lowered gently.
Operating the lever will release the pressure in the solar storage tank.
"To Turn Off the Water Heater"
70
on page 64.
Advertisement
Table of Contents
