How to Install a Gas Pool Heater

An outdoor pool with an attached hot tub.
What You'll Need
Gas pool heater
Measuring tape
Hacksaw
PVC pipe
Plumbing compound
Shut-off valve
Flex gas line
What You'll Need
Gas pool heater
Measuring tape
Hacksaw
PVC pipe
Plumbing compound
Shut-off valve
Flex gas line

Pool owners who want to extend the swimming season even after the onset of winter should install a gas pool heater. These increase the temperature of the water in the pool, thus making it possible to swim even in the colder months of the year. Water passes into the heater through the filter and is warmed in its combustion chamber. It is then passed back into the pool, allowing you to swim in comfortably warm water. Follow these steps to install your own before the temperatures start to drop.

Purchase Your Gas Heater

Gas pool heaters come in a variety of sizes that determine their cost. Purchase one that is sufficient for the size of your pool.

Select a Location for the Heater

When choosing an appropriate location, keep in mind the clearance distances you need above the unit and to its sides for safe operation. These distances, however, will depend on the size and model of your heater, so be sure to check the manufacturer's instructions for the information you need. You should also keep it as close to the filter as possible to avoid extra piping. Aim at installing it within two to five feet from the filter.

Channel Water into the Heater

Turn the filter off prior to installation, and begin plumbing the heater by measuring the distance from the return valve of the filter to the inlet valve of the heater. Cut and attach the PVC pipe there to this length. This will help channel the filtered water into the heater.

Pass Warm Water into the Pool

Measure and cut another piece of PVC pipe and run it from the outlet valve of the heater to the water inlet of the swimming pool. This will take warm water into the pool. Use a plumbing compound to tightly secure these pipes and joints.

Connect the Gas Supply Line and Electrical Power

Make sure you check with your regulatory authorities before you hook up the gas lines to the heater, as some locations require professionals to install gas connections. It is very likely that they will have to be inspected prior to pressurizing the lines. If not, install a shut-off valve at the end of your gas pipe and run a flex gas line from there to the heater inlet. Then, connect the 120-volt plug of your heater to an electric outlet. Install a covering over your outlet to protect it from the weather and plug the heater in.

Test the Setup

After your installation and setup are complete, you should test the unit to make the necessary amendments. Turn the pool filter back on first, and then turn the heater on and raise the temperature on the thermostat slightly. A fan will blow before the heater ignites. Check that the heater has a blue flame.

The temperature in the pool will rise shortly after you turn the heater on. Most units have flow sensors that detect water pressure and disable it from turning on if the water drops to a certain level, but keeping the power off when the pool is not in use is the best way to avoid accidents.