
The SunEarth solar collector is the heart of the
Cascade Drainback system. Simply stated, when the
sun is shining, heat energy is absorbed by the solar
collector’s all copper absorber plate and transferred
to the water circulating through the solar collector.
The system pump efficiently circulates this heated
water through the collector piping and integral tank
heat exchanger. As the water passes through the
heat exchanger, the heat in the fluid is transferred to
the potable water in your solar storage tank. As this
process is repeated during the average sunny day,
the temperature in your solar storage tank rises.
The differential temperature controller is the brain
of the system. The controller uses temperature sen-
sors to constantly monitor the temperatures at the
collector and at the tank. The controller automati-
cally turns the pump on when useful heat is avail-
able at the collector and turns the pump off when
there is insufficient solar heat available or the tank
has reached maximum temperature.
Depending upon the system demand, time of year
and the weather, the circulating pump may either
run intermittently throughout the day or constantly
for hours at a time.
Both single and double tank Cascade Drainback
systems are designed to accommodate two separate
modes of system operation. Your system can either
(1) serve as a preheater to your conventional electric
or gas water heater or (2) be bypassed entirely and
run 100% on utility power during inclement weather
or when maintenance is required. The installation of
an optional water heater time switch allows you to
control both the frequency and duration of supple-
mental electric resistance water heating.
Section 6 provides instruction in setting the system
for automatic operation in each of these two modes.
The water in the SunEarth collector and the solar
loop piping automatically drains back into the
drainback reservoir each time the circulating pump
turns off. Gravity drains the piping and provides
the freeze and overheat protection for your Cascade
Drainback system.
The system also can be manually drained in order to
protect the integrity of the collector and solar loop
piping if it is exposed to extended periods of disuse
or persistent hard freeze conditions below - 50°
Fahrenheit. (See Section 7 for instructions).
3) INSTALLATION REQUIREMENTS –
GENERAL
3.1 Permits:
The contractor shall obtain all required permits and
approvals.
3.2 Codes, Ordinances and Standards:
P.4
SYSTEM ORIENTATION
fig. 1