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SWIMMING POOL SOLAR HEATING SYSTEM
INSTALLATION MANUAL

MANUAL SYSTEMS Some systems can employ a manual control valve to control the flow of water thru the solar collectors, although this may reduce the overall heating capacity of the system. The manual control valve usually consists of a non-positively sealed 3-way valve as shown in Diagram 10. Water continuously flows through the solar collectors when the filter pump is on, but can be diverted manually by the pool owner if the pool becomes too warm or during extended cloudy weather. During a threat of freezing conditions it can also be diverted, by first shutting off the pool pump, allowing the collectors to drain, diverting the 3-way manual valve to the “bypass collector” position and shutting the isolation valves on the collector feed and return lines. A lower end cap on the collectors or any of the connecting hoses can be removed to make sure there is no standing water in the collectors. The filter pump can then be restarted to allow for normal pool filtration. During normal operation of the system when the 3-way valve is in the ‘bypass collector’ position all the water in the collectors should drain back through the 3-way valve (nonpositively sealed) when the filter pump shuts off. An alternate way to protect against sudden freezes can be accomplished by running a bypass line (1/8”-1/4”, 3-6mm) between the collector feed and return line above the isolation valves, if any. It is possible that a small amount of water may be present in the collectors when a non-positively sealed 3-way valve is used and the filter pump is on. If a positively sealed 3-way valve is used, a bypass line as mentioned above is mandatory to allow for collector drainage.

AUTOMATIC CONTROL SYSTEMS The performance of a solar pool heating system can be improved with the use of an electronic control and motorized 3-way valve. The control activates the motorized valve and either sends water thru the collectors for heating (or nocturnal cooling) or automatically bypasses the collectors when the pool is warm enough or insufficient sunlight is available. Refer to the manufacturer’s Instructions Included with the automatic equipment you use.

OTHER EQUIPMENT Some pools employ an automatic pool cleaner. This should be plumbed before the control valve to assure positive flow to the cleaner at all times. If the pool uses an automatic chlorinator, this should be plumbed after the outlet tee on the return to the pool.

FLOW RATES Table B - Flow Rates COLLECTOR SIZE   4x12 4x10 4x8 Recommended flow rate per collector, gpm/l 5.0/18.9 4.0/15.1 3.25/12.5 Minimum flow rate per collector, gpm/l 3.0/11.4 2.5/9.5 2.0/7.6 Maximum # collectors per row 10 12 14 In order to receive optimum results from collectors, the following recommended flow rates and number of collectors per row should be followed. When the system is running, all the collectors should feel uniformly cool to the touch, and there should be no residual air left in the pool return lines. If either of these two conditions persist, chances are that the flow rates thru the collectors are inadequate or the system is not properly balanced. A flow meter can be installed in the collector feed line to check on the flow rate. If the flow rates are within the limits as shown in Table B, then the system may not be properly balanced, especially with systems requiring multiple banks of collectors. Refer to the following section on Special System Layouts. If the flow rate is below the minimum as shown in the table above, then the pool pump horse power or pipe size should be increased, or a booster pump installed in some cases. If the long hoses on the inlet and outlet piping connections “suck in”, then slip a piece of 1 1/2” (50mm) pipe into the hose to prevent this. And also, if the flow rate is excessive (more than 10 GPM/(37.9l ) collector), or if the system pressure is greater than 30 psi, a bypass line should be installed between the collector feed and return lines above the 3-way valve to prevent problems with the collectors and connection hoses. If there is residual air in the pool return lines and the collectors do feel cool to the touch, refer to the section concerning the vacuum relief valve test on page 10.

OPTIONAL ISOLATION VALVES Isolation valves may be installed in the collector piping so that the pool may be operated while the collectors are being serviced or during freezing weather. Install a manually operated ball valve in the collector inlet line and a check valve on the collector return line. Both valves are available in the Optional Isolation Kit. Make sure that the arrow on the check valve is pointing away from the collectors, and that the ball valve and check valve are located as close to the control valve and outlet ‘T’, respectively. For further precautions in warm climates where pools are operated year round and periodic freezes can occur, a bypass line (small diameter tubing) can be located above the ball and check valve so as to prevent any accidental trapping of water in the collectors by the pool owner. To make sure no water is left in the collectors for servicing or during freezes, remember that the pool pump should be shut off, allowing the collectors to drain naturally, before the optional isolation valves are used.