Step 1
Locate the suction tube running from the lower intake of the jacuzzi tub to the pump. Measure and mark a 7 1/2-inch section of the suction tube. The section of tube should be in an area that's easy to access and large enough to accommodate the inline heater. Cut out the section of tubing with a saw and discard it.
Step 2
Unscrew the pipe fittings from the ends of the heater. Clean the cut ends of the suction tube with PVC primer. The primer cleans the PVC tube and prepares it for the cement, helping to ensure a water-tight bond. Clean about 2 inches up each pipe.
Step 3
Clean inside the smooth ends of the pipe fittings with the primer. Rotate the primer brush around the inside of the fitting several times to clean it thoroughly.
Step 4
Apply a thin coat of PVC cement to the inside of one fitting and one end of the suction tube. Slide the fitting onto the tube and turn it 1/4 turn clockwise. Hold the fitting in place for about 30 seconds. Repeat this process with the second fitting on the other end of the tube. When finished, you should have a gap in the suction tube with a male threaded fitting at each end.
Step 5
Place the included gaskets inside the female threaded fittings at each end of the heater. Position the heater in the gap in the suction tube. Thread the heater fittings onto the male fittings. Turn the fittings clockwise until they are tight.
Step 6
Run water through the tub with the pump off while checking for leaks at the heater fittings. Run the pump and continue looking for leaks. Tighten the fittings until any leaks stop.
Step 7
Place a wood block under the suction tube to support the added weight of the heater.
Step 8
Plug the heater into a GFCI-protected outlet with a sufficient voltage and amperage rating.