Power Cycling

• Perform troubleshooting steps to increase the water pressure to the correct level if your Hayward 350 pool heater is cycling on and off. The Hayward 350 pool heater should be activated at all times; power cycling is usually a symptom of water pressure problems. Check the water filter to see if it's excessively dirty and needs to be changed. Make sure all of the water valves are on, allowing water through the Hayward 350 heater. Check the water pressure switch to make sure that it is set to the correct PSI level. It's also possible that the thermostat may be calibrated incorrectly; check the thermostat and replace it if improperly calibrated.
  
  

Wrong Temperature

• Check your fuel source and thermostat if your Hayward 350 pool heater is not reaching your desired temperature. Make sure that the thermostat is set to the temperature you want. Check your fuel supply to ensure there are no connectivity issues or leaks. Have a certified technician check your thermostat for possible malfunction. If the thermostat is working properly, it may simply mean that your pool is losing heat faster than the Hayward 350 pool heater can add heat. Purchase either a thermal barrier, which will help your pool retain heat better, or a larger capacity heater.
  
  

Leaking

• Inspect the leak to make sure it's a leak and not just condensation. Condensation can occur if your Hayward 350 is heating extremely cold water, or it may just be a symptom of excessive water flow from an oversized pump. If the supposed leak is just condensation, check the bypass valve for any possible damage.
  
  Contact a certified Hayward service company if your Hayward 350 pool heater is experiencing leaking. A Hayward 350 heater leak is often due to chemical problems, which you should trust a trained service professional to fix. Leaks can be caused by chemical imbalances, damage from either sanitizer or winter-freeze solution, or may be the result of a failed joint. In any event, contact a certified Hayward service company.
  
  

Pilot Light Issues

• Clean out the pilot light area inside your Hayward 350 pool heater if the pilot light will not ignite. Periods of nonuse can lead to environmental clutter, such as cobwebs. Clear out any material that is preventing the propane gas from reaching the ignition spark. If the pilot light still won't ignite, call a service technician to check both the ignition spark and the pilot generator; either of them may need replacing.
  
  Protect the pilot light cabinet from extreme environmental factors to prevent the pilot light from going out. This is best accomplished by placing your Hayward 350 pool heater away from potential wind gusts, rain or sprinklers. If your pilot light continues to go out, clean out the pilot light area as previously described. Check your gas supply, and if there are problems, contact a service technician.