How to Install a Replacement Gas Pool Heater

how to install a replacement pool heaterReplacing your old gas pool heater is not such a complicated task.  Indeed, most pool owners hire a professional to replace their pool heater.  Many states require gas appliances to be installed by a licensed contractor; but buying it, placing it and plumbing it – can be DIY tasks.

To be certain that your replacement gas heater is installed correctly and is in accordance to local codes and regulations, consult a licensed contractor to supervise or inspect your work before firing your new pool heater.

Getting Ready for Heater Installation

Once you have purchased the correct size and type of pool heater (propane or natural), the first step in replacing your gas pool heater is to uninstall your current heater and clear the location where the new pool heater will be installed. Make sure your pool pump has been turned off at the circuit breaker, and that you shut off the gas supply to the heater, at the tank (propane) or at the gas meter (natural).

For electronic pool heaters, make sure that your heater is truly powered down by removing the power source. Consult and follow the owner’s manual of your existing pool heater, and disconnect the wires that come into the heater. If your replacement gas heater is the same as your old one, take note of how your old one is wired as you are disconnecting the wires. Your new heater may be wired the same way.

With the use of large channel locks or pipe wrenches, disconnect the gas line from where it connects to the heater. Be certain that the gas supply is turned off before this is done. Look for a union connection inside the heater (natural gas). Propane lines are typically a flexible copper tubing. Be careful not to crimp or bend the tubing during removal. Of course, no smoking or any open flames near the heater at this point.

Disconnect the plumbing for the pool water, where the pipes come in and out of the heater. If your heater has union connections, use large channel locks or big meaty hands to loosen the unions. Pool heaters without union connections may be plumbed in place, or may utilize heat sinks – metal tubes with unions on the bottom.

Look for a small, bare copper bonding wire attached to the base of the pool heater. Disconnect the bonding wire from the bonding lug and bend to the side, out of the way.

If your heater has a vent stack on top (and any heater installed indoors or inside of a shed should have proper venting), carefully remove the sheet metal pieces from the top, and inspect the pieces to be sure that there are no cracks or corrosion. Also check for bird nests and thick spider webs.

Now that you have disconnected the Power, the Plumbing, the Gas and the bonding wire, your heater should now be free to be removed from the pad. You’ll need a hand! Two people should be able to remove the heater fairly easily. If you’re by yourself, remove the heat exchanger from the pool heater first, which will lighten the load considerably.

BTW, a scrap metal yard will pay cash for the copper heat exchanger tubes. Brass headers will also have a recycle value. In fact, almost all metal components of your old pool heater can be recycled.

Heater Location

Once the area is cleared, place your replacement gas heater onto the location where it will sit. This is the best time to double check that the location you have chosen for your pool heater is in accordance to safety codes and regulations.

Following the new heater’s installation guide, make sure that there is sufficient room (in front of, behind, to the sides and above) for proper combustion and ventilation of your new gas pool heater.

Pool heaters must sit on a non-combustible base and have at least 24″ of clearance around all sides and clear sky above. This is VERY important! Pool heaters should also not be installed beneath or near any windows into the house, as they produce carbon monoxide and this exhaust can be fatal. Vitas Gerulaitis, a well-known tennis star, was killed in such a manner in 1994.

Pool heaters which are poorly maintained or installed incorrectly can also be a fire hazard; flame roll-out can ignite nearby combustible materials. Consult your owner’s manual for these very important considerations.

Ensure that shrubbery or trees have not overgrown too close to where the heater is going to be positioned. Trimming or removal of nearby plants and trees may be needed. Your new pool heater should sit several inches above the earth, free and clear of mulch or leaf piles and out of any danger of flooding.

Heater Electrical

Wiring for digital gas heaters is a simple task – follow the specifications and directions that came with your pool heater. If your replacement pool heater is identical to your old one, this step should be easier since you’ve noted how the existing heater was wired as you were disconnecting it. Securely fasten the conduit to the cabinet with a suitable conduit connector.

Double and triple check that all wires have been connected properly, the directions are usually very simple and clear. Take care to check that you’ve correctly connected your power lines as instructed.

Connect remote wiring, if using a remote controller system, again following the directions that have come with your replacement pool heater. The wires from the remote controller should never be combined with the high voltage wire in the same conduit, and therefore you will notice that pool heaters have two conduit installation holes in the side panel.

Heater Plumbing

Once the electrical has been installed, it is time to connect the plumbing for your pool system. Attach the PVC plumbing connection union nuts that come with your replacement pool heater. The gaskets that come with these connections should be lubricated with a silicone-based lubricant to ensure a sealed fit.

Take care to install the pipes into their respective inlet and outlet ports on the heater. I once was called out to troubleshoot a pool heater, and after much head scratching, discovered that the heater was plumbed backwards!

The front header or manifold should be clearly labeled with a sticker or an arrow pointing either towards (inlet) or away (outlet) from the pool heater.  A pressure relief valve is usually required by local codes, to bleed off any excess pressure – similar to a household hot water heater. Once you have made sure that all pipes and joints are correctly placed, secure them with a plumbing compound or PVC cement.

Heater Gas Line

The next step is to install the gas line – understandably the part of your new pool heater install that requires the most care. For propane heaters, your propane supplier will make a quick and secure connection for a nominal fee.

Consult your owner’s manual that came with your heater before making any gas line connection. If you are replacing the heater with the exact same model, the connection should be the same as before.

Once you’ve made sure that the incoming gas line is clean and corrosion-free, secure it to your heater using pipe dope on the threads. Use only sealants and fittings that are rated for gas supply.

After securely connecting the gas line to the gas valve, according to the pool heater owner’s manual, turn on the gas and test the entire gas line and fittings with some soapy water to check for leaks.

Before working with gas, check your local and state codes to see if a homeowner is prevented from working on gas. If so, consult a qualified gas contractor in this case – making mistakes in this area could be dangerous!

The next step of installing your replacement gas pool heater is to start up the filter pump and to check for water leaks. Once that is done, you are all set and ready to test fire your new pool heater. It may take a few minutes for the gas flow to reach the burners, but if it does not fire within a few minutes, double check the gas supply for leaks and blockages.

Indoor Pool Heaters

If the pool heater is to be installed indoors or in an outdoor shed or partial enclosure, be sure to properly vent the pool heater to the outdoors. Although this is completely explained in the owner’s manual, this can be tricky for the layman to do properly.

Consult a qualified HVAC company to properly vent a pool heater being installed indoors. Indoor heaters should also have a qualified gas contractor connect the gas supply line, and a permit should be pulled, as mistakes in indoor heater installation can be deadly!

Consult your owner’s manual to make sure that you’ve gone through all the steps to correctly and safely install a replacement gas pool heater.  Follow all local codes and regulations to set up your own pool heater – and you should have results as good as any professional pool heater installer, if not better!

Great work!

Martin Ratchev, tells us how to install a new gas pool heater
Martin Ratchev
InTheSwim Staff Blogger


How to Install a Replacement Gas Pool Heater — 1 Comment

  1. Pingback: Installing a Propane Swimming Pool Heater | InTheSwim Pool Blog

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