Replacing a pool or spa heater can be a complicated do-it-yourself job. So for most, its a good idea to enlist in the assistance of a pool professional. Positioning, ventilation, site layout and overall location are critical to a safe and proper functioning install.
Be sure to properly size the heater based on the demand of the site. Lift in temperature, wind and base temps are all part of the calculation when evaluating the proper unit. If the unit is fueled by gas propane or natural gas, verify that the supply will work for that particular unit. (Consult a plumbing professional to verify supply-side compliance.) During any repairs of this sort, turn off the circuit breaker and lock out the panel box.
1. Turn off the pump, disconnect the plumbing from the existing heater, and remove the old heater.
2. Examine the location of the heater, making sure that it is level and close to a gas line. This is the time to move the heater so that its safer and more efficient.
3. Plumb the replacement heater, following the manufacturers instructions.
4. Connect the electric line from the circuit breaker to the heater.
5. If installing a gas heater, connect the gas line to the heater.
6. Test the heater. Turn on the pump to force the water into the heater. Then turn the heater on and raise the thermostat slightly. Check to be sure that the fan is on and that the heater ignites.
The water temperature will rise gradually, as the water is circulated through the pump and heater.