Open Loop 13
15.
OPEN LOOP START-UP
After visual inspection of the complete system, it is
ready for filling and pressure testing. All drain
valves should be closed, all other valves opened.
The air vent caps should be loosened two turns to
allow air to escape the system. The cold water inlet
valve should hen be opened slowly and system
checked for leaks as it fills. When the system is
completely full, indicated by water escaping from
the air vent when the valve is depressed it should be
pressure checked with normal pressure for 30
minutes. Final inspection should then be made and
power to the controller turned on. If the sun is
shining and the storage tank is cool, the pump
should come on and water should flow through the
collector. The first water through the collectors will
be very hot but should stabilize in about 15 minutes.
The return lines from the collectors should be hotter
than the inlet lines and the collector glass should be
slightly warmer than ambient temperature.
Testing of the frost sensor can be made at night
when the pump is not normally working. A piece of
ice set on the sensor should be sufficient to turn the
pump on. The pump should turn off as soon as the
sensor has a few seconds to warm back up when the
ice is removed. Caution should be exercised when
working on the roof at night.
16.
OPEN LOOP MAINTENANCE
Maintenance of an open loop system is
straightforward. The tank should be partially
drained every 6 months to allow minerals to be
removed preventing scale build up (this is
recommended for all water heaters). The wye
strainer should be cleaned at least once a year or
more often if harsh water conditions exist. The
power should be switched off, the piping drained,
and the screen removed and cleaned.
The collector glass should be kept clean for best
system performance. Rainwater will usually suffice
but a garden hose can be used during dry weather.
The air vent caps should be loosened two turns for
proper operation and best system performance.