3.5
System Startup
The startup of the solar system is done only after everything is completely installed and
the tank filled with water. The electrical power may then be connected.
Turn the collector controller ON with the manual switch. Allow water to flow until it
begins to return into the tank. Set the flow rate with the flow meter above the collector
pump(s) to 0.025 GPM per square foot of collector. Turn the controller switch to the
AUTO position. If the collectors are hot, the system should run by itself. If the system
will not run by itself when the collectors are known to be hot, refer to the trouble
shooting section.
If the collectors are not hot, the following test will indicate a good controller. With all the
sensor wires installed, set the controller switch to the AUTO position. Refer to Table
3.3. Connect a low value resistor (low R = hot) across the COL terminals and observe
the controller response. The system should turn on, since the COL terminals appear
"hot". Note that a low value resistor corresponds to a hot sensor, and a high value
resistor (hi R) corresponds to a cold sensor. The third row of the table tests the high
limit control.
Table 3.3 Delta-T Controller Tests
HIGH / COL
LOW / STO
RESULT
terminals
terminals
Collector Pump is
OPEN(cold)
OPEN(cold)
OFF (no solar)
SHORT (hot)
OPEN (cold)
ON (proper run)
SHORT (hot)
SHORT (hot)
OFF (Hi limit)
OPEN (cold) = high R (~100k
Ω
)
SHORT (hot) = low R (~1
κΩ
)
The same test can be applied with the sensor wires removed from the terminals
to test wiring and sensor problems.
HoloTech
tm
Solar Installation Manual
17
Caution
Do not operate a controller until all plumbing has been
completed and the tank is full of water. Pumps may be
damaged if run dry. Do not work on an electric water
heater with the power on.