Rheem SolPak Use and Care Manual - Page 19

flow meter is recommended as an optional system component. A flow meter allows you to monitor and adjust the flow rate through the piping and also to visually inspect the HTF fluid quality. Set the controller to the "off" position and proceed to the next step. 4.9.4 Mix the Dowfrost HD propylene glycol and distilled water mixture in accordance with Table 4 and Table 5 in a large clean bucket. You will need a second empty bucket as well. The charging process also will require a low flow diaphragm pump (Flojet or equal) to fill and pressurize the collector loop. Connect the discharge side of the pressure pump to the upper isolation/drain valve (No. 7) Place the pump suction side hose in the glycol solution. Close the isolation ball valve (No. 7) and connect a second hose to the lower isolation/drain valve (No. 6). Place the other end of the hose in the empty bucket. Table 4 Percent (volume) Glycol Concentration Required Temperature F 20 10 0 -10 -20 -30 -40 -50 -60 For Freeze Protection 18% 29 36 42 46 50 54 57 60 For Burst Protection 12% 20 24 28 30 33 35 35 35 Table 5 Total Collector Loop Fluid Capacity In Gallons* Open the upper drain valve and allow the pressure from the expansion tank to push the water in the glycol loop back to prime the pressure pump. When the hose in the bucket containing the glycol mixture stops bubbling you may begin charging the collector loop with glycol. With both drain valves (No. 6 & 7) faucets now open, run the Flojet pressure pump until the pinkish glycol mixture begins flowing into the empty bucket. Quickly switch the hose from the empty/return bucket to the bucket containing the glycol mixture. Continue to circulate the fluid using the pressure pump until the bubbling has stopped and the air has been purged. 4.9.5 After charging the collector loop, shut the lower drain valve (No. 6) and let the pressure pump drive up the loop pressure to the appropriate level (Generally in the range of 25 PSI). To more accurately calculate the proper pressure measure the height of the solar collector above the solar storage tank and divide this number by 2.31. Then add 20 PSI to this number. As a word of caution, the pressure in the glycol loop should not exceed 45 PSI when the system is operational on a good sunny day. Contact your solar contractor if the charged collector loop pressure exceeds this threshold. Your solar water heating system must be charged and the fluid quality maintained by an experienced contractor. If the system is drained during the winter, or you notice a significant drop in collector loop pressure, contact your installation contractor immediately for service. The glycol HTF provides the freeze protection for your system and must be properly maintained. An experienced contractor should periodically check the HTF fluid quality. 1 Collector System 2 Collector System 4 Gallons 5 Gallons 19