How To Change the Pentair Rainbow 300/320 Lid O-Ring

This guide provides a step-by-step procedure for replacing the Pentair Rainbow 300/320 Lid O-Ring.In a Pentair Rainbow chlorinator, the most common part that needs to be replaced would be the lid o-ring. Finding the correct o-ring and ultimately replacing it, is a common duty pool owners will find themselves doing. 

1. Before starting, I cannot stress that you should do this in a very well-ventilated area, outdoors if possible. Chlorine gas is very dangerous and should be taken seriously.

2. First, turn of the pump and filter. Once the pump and filter have been turned off, remove the pvc plug.

3. Once the plug is off, remove the lid off of the chlorinator. If the lid is difficult to remove, the lid wrench will make it easier.

4. Once the lid has been removed, the o-ring should be visible. Using a small flat head screw driver, remove the o-ring.

5. Clean the inside of the lid using a brush or a rag and warm soap and water.

6. With the new o-ring in hand, apply a generous amount of lubricant o-ring making sure it is well coated. The lubricant will help prevent the o-ring from getting “pinched” when the cover is threaded back on. The application of lubricant will also help protect the o-ring from corrosion caused by the chlorine.

7. Re-install the pvc plug.

8. Place the new o-ring back into the lid and push it into place. Check to make sure that the new o-ring fits and is seated properly inside of the lid.

9. You can now screw the lid back onto the chlorinator.

10. Once the lid has been installed onto the chlorinator, you can turn on the pump and filter to check for leaks. If there are leaks present, turn off the pump and filter and review the steps above.

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