Specifications

www.aetsolar.com Open Loop / PV - Page 14
STORAGE TANK PLACEMENT
To minimize expense and heat loss, the tank should be placed near the collectors and central to points of
greatest water demand. It should be located in as warm a spot as possible. It should be located with
adequate ventilation, with a minimum of 6-8 inches of clearance and with ready access to controls and
serviceable parts.
Provision should be made to prevent water damage in case of leakage. A catch pan with a minimum of
3/4” drain line at least 2” in height may be installed and pitched for proper drainage where the tank is
installed in or above the living space. Electrical service of 240V should be available for the element and
110V for the pump and controller.
SENSOR MOUNTING AT STORAGE TANK
On the closed loop Rheem tanks the heat sensor mounting is located behind the round cover located at
the bottom front of the 80 gallon storage tank.
Procedure:
1. The round cover located on the bottom front of the tank should be removed and the fiber glass
insulation pushed aside so that the wall of the tank is accessible.
2. Remove the ½” brass plug from the tank.
3. After sealing the ½” lug sensor with teflon tape or pipe tape, screw it into the ½” threaded hole.
4. Attach 18/2 sensor wire to the wires of the sensor. It does not matter which sensor wire is
attached to the thermostat wire.
5. Run the thermostat wire up the tank to the controller and attach it to the terminals marked tank or
water.
6. Replace the insulation and cover.
OPEN LOOP FLUID HANDLING SYSTEM
An Eagle Sun open loop solar water heater operates by circulating water from the storage tank to the
solar collectors when the collectors are at a higher temperature than the tank. This function is controlled
by a differential temperature controller with heat sensors. When the collectors are warmer than the water
inside the tank, the controller switches on the pump. (Figure 16).
A recirculation feature of the controller provides freeze protection. When the sensor at the collector
indicates freezing temperatures, the pump is switched on and warm water is circulated through the
collectors until warmed. The pump is then automatically switched off. This cycle repeats periodically until
freezing conditions no longer exist. When a hard freeze is imminent or a power failure occurs, the system
should be drained by closing the two ball valves that isolate the collector loop and opening the two drain
valves that allow the collectors to drain.
The system also includes a freeze protection valve at the collector outlet pipe. This valve is designed to
open at a set temperature 35-45°F and allow fluid to pass across the collectors to prevent freezing of the
collector manifold. When operating properly the valve will drip water until a suitable temperature is
reached at the valve.
Automatic air vents in the top of the system prevent air locks. Care should be taken that no air can be
trapped in piping to and from the collectors. Water returns to the tank from the collectors via a drop tuber
that extends halfway down the interior of the tank. This allows the returning water to stratify properly.
A check valve in the return line from the collectors prevents thermosiphon losses during the night.
Temperature and pressure relief valves protect the system from damage.
A backup electric element is provided in the top of the tank to supply hot water during inclement weather.
Power required is 240 volts.