The water supply from a rainwater tank in a met-
ropolitan area is likely to be corrosive due to the
dissolution of atmospheric contaminants. This may
result in pH of less than 6.0. It is recommended an
analysis on the water from a rainwater tank be con-
ducted prior to connecting this type of water supply
to a SunSiphon solar water heating system.
4.2.2 SATURATION INDEX
The saturation index is used as a measure of the
water’s corrosive or scaling properties. In a corro-
sive water supply, the water can attack copper parts
and cause them to fail.
Where the saturation index is less than –1.0, the
water is very corrosive and warranty does not apply
to a copper parts or the stainless steel tank.
In a scaling water supply calcium carbonate is
deposited out of the water onto any hot metallic
surface.
Where the saturation index e0.80, warranty
does not apply to a standard watts density heating
element. A low watts density heating element or a
two tank an indirect solar water heater must be used
for warranty to apply to the heating unit or solar col-
lector. Water which is scaling may be treated with
a water softening device to reduce the saturation
index of the water.
4.2.3 SUMMARY OF WATER CHEMISTRY
ADVICE AFFECTING WARRANTY
The following table defines acceptable potable water
quality conditions. If the supply water exceeds any
of these levels please contact SunEarth before
installing the system.
4.3 SunSiphon Roof Mounting Procedures, Materials
& Methods
In accordance with the preceding discussion, locate
the SunSiphon on a south facing roof that lies
within 135º southeast and 225º southwest of True
South. If the installation lies between 90º east and
135º southeast or 225º southwest and 270º west you
will need to add a collector or use larger collectors.
Remember that True South varies slightly from
magnetic south (180º) on the compass rose depend-
ing upon the exact location of the installation.
Your SunSiphon system must be mounted in accor-
dance with the materials and methods detailed in the
drawings and figures in this manual. Note carefully
the mounting requirements for different roofing
materials and surfaces. Always use SunEarth’s
integrated Solar Strut anodized aluminum mounting
hardware and stainless steel fasteners when mount-
ing the unit.
Secure the Solar Strut mounting hardware with
stainless steel lag, hanger bolts or threaded rod
directly to the rafters or support cross bracing. Use
Table 2 to determine the minimum number of Solar
Strut or standoff flange mounting supports required
for each solar tank option. Attach the SunSiphon
storage tank to the Solar Strut mounting hardware
with stainless steel earthquake/hurricane straps and
a stainless steel sliding nut, bolt, lock washer and
flat washer. Span as many rafters as possible when
mounting the solar storage tank.
Please note when securing the solar collectors to the
SolarStrut mounting hardware that the collectors
must be installed with a very slight 1” rise to the
right to allow for proper thermo siphoning of the
HTF (see figure 10).
P.7
SUNSIPHON
fig.8
Table 1
Description Maximum Recommended Level
pH
6.0 or Above
Chlorides
Less Than 250 mg/L
Saturation Index (SI)
-1.0 to + 0.8
fOR ROOf TRUSS OR fRAMINg MEMBER SPAcED AT
16” O.c.
