
heater to the desired hot water temperature. 100%
Utility power mode operates by supplying mains
water directly to the auxiliary heater whenever there
is hot water draw, bypassing the solar storage tank.
Follow the instructions for the single tank system
for setting the thermostat, gas or electric heater
for automatic operation. The ball valves going to
and from the solar storage tank (Component # 6
& 7) must be closed while the bypass ball valve
(Component #5) must be open.
7) SYSTEM SHUT DOWN AND ISOLATION
PROCEEDURES
Your Cascade Drainback solar water heating system
is designed so that the key components can be easily
isolated for emergency repairs or routine mainte-
nance. By shutting a single valve you can isolate the
entire system from the pressurized cold water sup-
ply line (COMPONENT #8). In the case of a stor-
age tank or fitting leak immediately shut this valve
and call your installation contractor for service.
The collector loop can be quickly drained if a leak
is detected or for routine maintenance. Set the
SunEarth control to the ‘OFF’ position. Next, attach
a hose to the lower boiler drain (COMPONENT
#11) and open the valve to drain the system.
CAUTION: THIS WATER MAY BE
EXTREMELY HOT!
In two tank systems the solar storage tank can be
isolated from the back-up water heater. Set the
valve handles to the 100% utility power configura-
tion as outlined above. By closing these valves the
tank can be serviced or replaced. The operation of
the back-up water heater will not be affected.
8) SUMMER VACATION PROCEDURES
Solar water heating systems can build up very high
temperatures during summer months if there is no
daily draw on the system. If a short summer vaca-
tion is planned the best way to avoid overheating
in a drainback system is to set the SunEarth control
to the ‘OFF’ position. The pump will not circulate
during the day and the system will not “gain” any
additional heat.
For extended vacations of a month or more SunEarth
recommends that you cover the panels with a suit-
able opaque material. Stagnation conditions can
have an adverse effect on the internal collector
piping if the panel is left unprotected. SunEarth’s
collector warranty specifically excludes stagnation
conditions in excess of sixty days.
Remember to reset the SunEarth control to the
‘AUTO’ position upon your return and check the
system for proper operation and draining by moni-
toring the water levels with the pump on and off.
9) MAINTENANCE AND
TROUBLESHOOTING
The following simple procedures are intended to
optimize the performance of your Cascade Drainback
solar water heating system and also to extend the life
of the primary components.
9.1 Checking the Water Level
It is important that the drainback reservoir remains
full for proper system operation. To check the fluid
level, set the SunEarth control to the ‘OFF’ posi-
tion and allow the fluid in the array to drain into the
drainback reservoir. For systems installed with an
optional flow meter or sight glass, check to see that
the fluid is not less than 1” from the top of the meter.
If your system does not have a flow meter, unscrew
the pressure relief valve (COMPONENT #9) and
dip a wooden dowel into the threaded copper fitting
to check that the fluid level is not more than 6-8”
below the valve fitting. If a small amount of fluid is
needed to bring the reservoir up to the proper level,
pour it directly into the (COMPONENT #9) fitting
port. Rewrap the thread with Teflon tape and rein-
stall (COMPONENT #9). You may also follow the
instructions in section 4.13 for charging the system
if more water is required.
Please remember that over time you WILL lose
some fluid in the solar loop piping. If the water
level is not properly maintained you may do irrepa-
rable damage to your circulating pump. Check your
fluid levels at least once a year.
9.2 Replacing the Anode Rod
The second most important component in your sys-
tem, at least from a longevity standpoint, is often
ignored and never seen. We are referring to the sac-
rificial “anode rod” installed in your solar storage
tank. Typically constructed from magnesium, anode
rods are installed in “glass lined” water heaters and
storage tanks to inhibit corrosion.
As the name implies, the “sacrificial” anode rod is
consumed so that the tank lining is not. At a cer-
tain point in the process, the anode rod is no longer
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