Rheem SolPak Use and Care Manual - Page 21

Section 6: Three Modes of System Operation 6) THREE MODES OF SYSTEM OPERATION Two Tank System Instructions: Both single and double tank systems are designed to accommodate three separate modes of operation. Your solar water heating system can, (1) provide 100% solar operation during good weather, or (2) serve as a preheater to your electric or gas water heater adding solar energy when and as available, or (3) completely bypass the solar collector loop and solar storage tank and run 100% on utility power during inclement weather. 6.4 100% Solar Operation Follow the instructions for single tank systems above. You also must change the position of the three way ball valves above both the solar storage tank and the back-up water heater (Nos. 24 and 25). Valve handle No. 24 must be in the horizontal position. Valve handle No. 25 must be in the vertical position. (See Figure 19a, 100% Solar Operation) Single Tank Operating Instructions: 6.5 Solar Preheat 6.1 100% Solar Operation: Turn off the heating element to your solar storage tank. If a water heater time switch has been installed, set the switch to the "off" position. If you have a mechanical timer remove the trippers from the face of the switch. 6.2 Solar Preheat Leave the heating element to your solar storage tank on and set the tank thermostat to the lowest acceptable temperature setting. The heating element will come on only when the tank temperature falls below the thermostatic set point. If the solar heated water entering the tank is warmer than the thermostat set point, the heating element will not come on. If you have a water heater timer, you may preset the timer to turn the heating element on and off at specified times throughout the day if desired. Follow the instructions for the single tank system for setting the heating element for automatic operation. The three way valve above the solar storage tank (No. 24) must be in the vertical position. Each valve handle (Nos. 24 and 25) must be placed in the horizontal position. (See Figure 19b, Solar Preheat) 6.6 100% Utility Power Follow the instructions for the single tank system above. All three way ball valves above the heaters (Nos. 24 and 25) must have the valve handles placed in the horizontal position. (See Figures 19c, 100% Utility Power and 19d, Valve Position Diagram) 6.3 100% Utility Power Leave the heating element to your solar storage tank on and close the isolation ball valves in the collector loop (Nos. 6 and 8). In this mode of operation you must turn off the circulation pump. To turn the pump off open the controller and change the operational setting from automatic to off. Failure to turn off the pump can quickly damage the pump motor, shaft, bearings or impeller. 21