8) SUMMER VACATION RECOMMENDATIONS
AND PROCEDURES
Solar water heat-
ing systems can
build up very high
t e m p e r a t u r e s
when there is no
daily load or draw
on the system. If
an extended sum-
mer vacation is
planned (4 weeks
or more) it is advis-
able to either
cover the solar col-
lectors with an
opaque material or
to manually drain
the collector loop HTF. SunEarth recommends
that you cover the collectors if practical.
If you choose to drain the HTF in the collector
loop follow these steps:
8.1 Turn the circulation pump toggle switch to
the off position (No. 21)
8.2 Connect one end of a garden hose to the
purge/drain valve (No 11) and place the other
end in a five gallon bucket. Open the valve and
gravity will drain the heat transfer fluid into the
bucket. A licensed recycler, reclaimer or inciner-
ator must dispose of the Dowfrost HD.
DO NOT
DUMP DOWFROST
HD INTO A STORM
SEWER, ON THE GROUND OR INTO ANY
BODY OF WATER.
BE CAREFUL. THE HTF MAY BE EXTREMELY
HOT!
8.3 If the system is installed with an optional
time clock make sure the clock is not preset to go
“ON” during your absence. If you have a
mechanical time switch, remove the “on” tripper
from the clock face (No. 32).
When you return home contact your service con-
tractor to recharge the system with HTF. After
recharging the system, flip the circulating pump
toggle switch to the “on” position (No. 21).
9) MAINTENANCE AND TROUBLESHOOTING
The following simple procedures are intended to
optimize the performance of your SolaRay solar
water heating system and also to extend the life
of the primary
components.
9.1 Fluid Quality:
It is extremely
important to moni-
tor the quality of
the Dowfrost HD
HTF on a periodic
basis. The chemi-
cal composition of
the heat transfer
fluid may change
over time. System
pH must be main-
tained between 8
and 10 to avoid
damage to the collector loop and absorber plate
piping.
The specified glycol HTF is Dow Chemical
"Dowfrost" HD. An extremely complete manual
is available from the Dow Chemical Co. by calling
1-800-447-4369 Extension DOWFROST. Dow
Chemical's "Engineering and Operating Guide
for Dowfrost and Dowfrost HD" describes in
detail the necessary procedures to maintain the
integrity of the HTF. Ask your installation con-
tractor to establish a maintenance schedule to
inspect, balance or replace the glycol HTF as
needed.
9.2 The second most important component in
your system, at least from a longevity standpoint,
is often ignored and never seen. We are referring
to the sacrificial "anode rod" installed in your
solar storage tank (No. 18). 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
certain point in the process, the anode rod is no
longer completely effective and the corrosive
processes begin to eat away at the tank's glass
lining. In time the solar storage tank, like any
other gas or electric water heater, will begin to
leak. The process is not reversible and the tank
must be replaced.
System temperatures and water quality affect the
P.15
VALVE POSITION DIAGRAM
2-TANK SYSTEM
fig.18d
