Pool heater beside a pump and filter on a sunny equipment pad against a stucco wall in a Phoenix backyard

Pool Heater Repair in Phoenix

A heater that will not fire usually shows up on the first cool evening of fall, or the morning you planned a swim in February. One free call, any hour, puts you through to an independent, locally owned pool service company in the Valley.

Call (623) 240-0428 Match your heater symptom

Pool heater repair in Phoenix is a seasonal job with a long quiet spell in between. Through most of the year nobody in the Valley needs a heater; the sun does the work. Then fall nights cool off, the heater gets switched on for the first time in months, and whatever dried out, scaled up or got packed with leaves over the summer gets tested all at once.

This page starts with gas safety, because most pool heaters here burn natural gas a few feet from where people sit. After that it explains the three kinds of heaters you will find in Phoenix backyards, what usually goes wrong with each, what you can safely check and what to ask the company you reach.

Phoenix Pool Cleaning Pro does not repair heaters. It is a free phone line. Call (623) 240-0428 any hour, an automated assistant asks what the heater is doing, and the call is transferred to an independent, locally owned pool service company. That company works out what is wrong with the heater, prices the fix, carries it out and sends you its own bill.

Gas safety comes before any pool heater repair

Natural gas has no smell of its own. Southwest Gas, the gas utility for much of the Valley, explains that it adds a harmless chemical called mercaptan so a leak smells like rotten eggs. If you notice that smell near the equipment pad, the heater can wait.

Do not

Do not touch the heater's controls, the thermostat or any electrical switch near the smell, on or off.
Do not smoke, strike a match or use a lighter.
Do not try to find the leak, open the heater cabinet or turn gas valves.
Do not assume a neighbor has already reported it.

Do

Leave the yard and the house right away, and get everyone else out too, children and pets included.
Once you are well away from the smell, phone 911 and then the Southwest Gas emergency line, 877-860-6020. Southwest Gas says it answers that number around the clock, for customers and non-customers.
Stay away until the utility or the fire department tells you it is safe.
Also call if you hear a hissing or roaring sound from a gas line or appliance; Southwest Gas lists that as a leak sign too.

Gas work is never a homeowner job. Pool heater repair that involves the gas supply, the gas valve or the burners belongs to a trained technician, and new or altered gas piping belongs to a contractor licensed for it.

Gas heaters, heat pumps and solar: which one is in your yard?

Before you call, it helps to know what kind of heater you have, because each one fails differently and needs a different kind of repair. Look at the equipment pad. A gas heater has a gas pipe running into it and a vent on top or on the side. A heat pump looks a bit like the outdoor unit of a home air conditioner, with a large fan and a coil, and no gas line. A solar system has panels on the roof or a rack, with pool water piped up to them and a valve that sends water up or past them.

Comparison of gas pool heaters, heat pump pool heaters and solar pool heaters
Heater type	How it makes heat	Where it fits in Phoenix	Typical trouble spots
Gas heater	Burns natural gas (or propane) and passes pool water through a heat exchanger above the flame	Fast warm ups for a weekend swim or a spa that is heated now and then	Ignition, gas supply, pressure or flow switch, sensors, control board, scale inside the heat exchanger, a blocked vent
Heat pump	Uses electricity to run a fan and compressor that pull heat out of the outdoor air and move it into the water	Holding a steady temperature through the mild part of the year	Flow, a dirty or bent coil, the fan motor, refrigerant leaks, sensors, the control board
Solar	The pool pump pushes water through collectors in the sun; the pool itself stores the heat	Stretching the season in spring and fall, with the existing pool pump doing the circulating	Valves and controllers, sensors, leaks in roof panels or piping, a pump that runs at the wrong hours

Why heat pumps suit much of a Phoenix winter

A heat pump moves heat that is already in the air. That means it depends on the air being warm enough. The U.S. Department of Energy says heat pump pool heaters work best when the outdoor air stays above about 50 degrees, and they lose efficiency as it gets colder.

Phoenix winters sit mostly on the right side of that line during the day. The National Weather Service's 1991 to 2020 normals for Phoenix put the average January high at about 68 degrees and the average January low at about 46 degrees. In plain terms, a winter afternoon is comfortably warm enough for a heat pump, while the coldest hours before sunrise dip below that mark. That is why many heat pump owners set them to run in the daytime. If a heat pump runs fine in the afternoon but struggles before dawn, that may be normal behavior rather than a fault, and it is worth asking the technician about.

Gas heaters do not depend on air temperature, and they warm water quickly, which is why many Valley homes with a spa keep one. Fuel cost is the trade-off, so it is worth comparing running costs before replacing one type with another.

Pool pump and plumbing beside a tall filter tank against a sunlit stucco wall

Pool heater symptoms and what they often point to

Use this to describe the problem when you call. The middle column is safe for any homeowner. The last column is for the technician only.

Pool heater symptoms, likely causes, safe homeowner checks and what a technician tests
What you notice	Common causes	Safe for you to check	What the technician tests
Display is blank, nothing happens	No power to the heater, a tripped breaker or GFCI, a blown fuse, a failed control board or transformer	Reset a tripped breaker or GFCI once. If it trips again, leave it off and call	Supply voltage, fuses, transformer and board
Display is on but shows a flow or pressure fault	Pump off or on too low a speed, a dirty filter, full baskets, a closed valve, a bad pressure or flow switch	Pump running, skimmer and pump baskets empty, filter pressure gauge reading, valves in their normal positions	Flow through the heater, the switch itself, bypass valves, internal scale restricting water
Gas heater clicks or tries, but never lights	Worn igniter or ignition module, gas supply problem, a fault in the gas valve, a blocked air intake	That the heater is on and calling for heat. Nothing inside the cabinet	Ignition sequence, gas pressure, valve, burner tray and air path
Lights, then shuts off, over and over	Sensor or high limit tripping, scale in the heat exchanger, low flow, venting trouble	Filter gauge and baskets, then stop and call	Sensors and limits, temperature rise across the heater, exchanger condition, vent
Runs but the water barely warms	Heater too small for the pool, heat pump in cold air, scaled exchanger, timer window too short, no cover on cold nights	Timer or automation schedule, set temperature, the air temperature at the time	Output against the heater's rating, refrigerant on a heat pump, exchanger, sizing
Water leaking from the heater	A cracked or corroded heat exchanger, failed gaskets or unions, a freeze crack on a cold night	Where the water is coming from, without opening the cabinet	Exchanger, headers, gaskets, unions and drain plugs
Soot, a burnt smell or a loud whoosh at ignition	Blocked burners or vent, debris or nests in the cabinet, a combustion problem	Turn the heater off at its controls and call. If you smell gas, leave and follow the steps above	Burners, combustion, vent, cabinet and gas valve

What wears out Valley pool heaters

A few things about Phoenix are hard on pool heaters, and knowing them helps you understand what a technician finds.

Hard water and scale

The Valley's tap water is hard, meaning it carries a lot of dissolved calcium and magnesium. The City of Phoenix's 2025 water quality report lists total hardness of 172 to 302 parts per million across its system. Heat makes calcium drop out of water faster, so the hottest part of the pool system, the heat exchanger, is where scale tends to build. The Department of Energy notes that scale in the burner or heat exchanger can lower a gas heater's efficiency over time. Scale also narrows the water passages, which can lead to overheating, noise and sensor trips. Keeping the water balanced, covered on our pool cleaning and weekly maintenance page, is the best way to slow it.

Low water flow

Most pool heaters have a pressure or flow switch that keeps them from firing unless enough water is moving. A clogged filter, full baskets or a variable speed pump set to a very low speed can all keep that switch open, and the heater then shows a fault even though nothing inside it is broken. That is why a dirty filter is one of the first things to rule out. Our pool filter cleaning page explains what the pressure gauge is telling you.

Months of sitting idle

A heater that sits from spring to fall in the Phoenix heat can collect leaves, dust and nests in the cabinet and air openings. Summer monsoon storms and dust storms blow debris against the equipment pad. When the heater finally lights in the fall, that debris can block air, foul the burners or show up as a burnt smell. A quick look around the heater before the first cool night, without opening it, catches the obvious problems.

Two hands turning a wrench on an old cast pool pump in a workshop

Safe checks before you call

None of these involve gas, wiring or the inside of the heater. They are the same checks a pool technician starts with, and doing them first can save a service visit for something simple.

Confirm the pump is running and that the timer or automation schedule gives the heater time to run.
Empty the skimmer and pump baskets and look at the filter pressure gauge. A reading well above its usual clean number points to a dirty filter.
Check the heater's own controls. It should be on, set to pool or spa as you expect, and set above the current water temperature.
Look for a tripped breaker or GFCI. Reset it one time only. If it trips a second time, leave it off and phone for help.
Write down any error code or message on the display. It helps the company you reach.
Look, without touching, around the heater for leaves, nests, water on the pad or soot on the cabinet.

Pump running, baskets empty, filter clean and still no heat? Call any hour and say whether it is a gas heater, heat pump or solar, what the display shows and where in the Valley you are.

Call (623) 240-0428

Repair or replace the heater

Many heater problems are repairable, including the heat exchanger in some cases. The decision usually comes down to the age of the heater, which part failed and how often it has needed work.

Repair usually makes sense when

The fault is a sensor, switch, igniter or another replaceable part.
The problem was low flow, scale or debris that can be cleared.
The heater is fairly young and has not needed much work.
The cabinet, exchanger and base are in good shape.

Replacement is worth pricing when

The heat exchanger is cracked, burned through or badly corroded on an older unit.
The same fault keeps coming back after repairs.
Parts are hard to get for the model.
You heat the pool more or less often than when the heater was chosen, so a different type might fit better.

If you do replace a gas heater, efficiency has improved. The Department of Energy set a federal minimum thermal efficiency of 82 percent for gas pool heaters made on or after April 16, 2013, and says some gas pool heaters now reach 89 to 95 percent. Ask the company to explain the efficiency, size and gas supply needs of anything it proposes, and ask about a heat pump or solar if you heat the pool regularly.

Who may work on a pool heater in Arizona

Arizona's Registrar of Contractors (ROC) licenses contractors. Its R-6 Swimming Pool Service and Repair classification covers servicing pools and making minor repairs to pools and their equipment, but the ROC lists gas lines, plumbing connections to a drinking water system, gas chlorine systems and electrical work beyond the first disconnect as outside that classification. So a pool company may be able to replace a heater's igniter or sensor, while running or changing a gas line calls for a contractor licensed for gas piping. Ask which license covers the job you are being quoted.

Questions worth putting to the pool company

How much is the service call or diagnostic fee, and does it go toward the repair?
What exactly failed, and can you show me?
Is there scale in the heat exchanger, and what does that say about my water balance?
Will I get a written price before work starts?
If gas piping is involved, who does that part, and what is their ROC license number?
What is your ROC license number and classification?

Hand holding a pool water sample vial at the water surface — Balanced water protects the heat exchanger. A home test kit is a safe way to keep an eye on it.

Pool heater repair in Phoenix through the free line

There is no charge to call. You explain the heater problem one time, and the pool company gets a brief summary of it before it comes on the line. When no one there is free, the line takes your name, number, part of town and what the heater is doing, and sends that to the company for a return call. Any fee, the visit time and the repair are settled between you and the company.

Call the numberAn automated assistant answers (623) 240-0428 day or night, weekends included.
Describe the poolSay what is going on: cloudy or green water, a pump that hums, a heater that will not fire, scale on the tile, and which part of the Valley you are in.
Get put throughThe call is transferred to an independent, locally owned pool service company, which hears a short summary of the problem before it picks up.
Deal with them directlyThat company looks at the pool, quotes, does the work and bills you. If it cannot answer, your name, number, area and problem are passed along so it can call you back.

About this line: Phoenix Pool Cleaning Pro is a free phone line, not a pool company. It answers your call and connects you with an independent local pool service company, which inspects, quotes and does the work, and which you pay directly. Companies may pay a referral fee. You never pay the line. See how the line works.

Check the license first. Arizona's Registrar of Contractors (ROC) licenses contractors, and its residential classifications include R-6, Swimming Pool Service and Repair. Repairs, equipment replacement and resurfacing generally call for a licensed contractor; whether a cleaning-only service needs a license is not spelled out, so ask the ROC if it matters to you. Ask the company for its ROC license number and look it up on the ROC contractor search (opens in a new tab) before work begins. The line does not check this for you.

Heater help across the Valley

The line takes pool heater calls from Phoenix and the towns around it.

Common questions

I smell gas near my pool heater. What should I do?

Leave the area right away and tell everyone else in the yard and house to leave too. Do not flip switches, touch the heater controls, use a lighter or start a car near the smell. When you are well clear of the yard, phone 911 and Southwest Gas at 877-860-6020. Southwest Gas says that line answers day or night and that you can call whether or not you are a customer. Stay away until the gas utility or fire department says it is safe.

Why is my pool heater not working?

The most common reasons are simple ones: the pump is off or running too slowly, the filter is dirty, the heater is switched off at its controls, or the timer has no heating window. Most heaters will not fire unless enough water is moving through them. After that come worn parts, such as the igniter, a pressure or flow switch, a sensor or the control board, and mineral scale inside the heat exchanger. Clean the baskets and check the filter gauge, then call and describe any error code you see.

Can you repair a pool heater heat exchanger?

Sometimes. A heat exchanger that is scaled up can often be cleaned, and leaking gaskets or fittings around it can be replaced. An exchanger that is cracked, burned through or badly corroded is usually replaced as a part, and on an older heater the cost of that part is often the point where people ask about replacing the whole heater. A pool technician should show you what failed before you decide.

How often should a pool heater be serviced?

The U.S. Department of Energy says to follow your owner's manual for a maintenance schedule and that a gas pool heater will probably need a tune up once a year. It also notes that scale in the burner or heat exchanger can lower efficiency over time, which matters in the Valley because the water is hard. Fall, before the first cool nights, is a sensible time to have it looked at.

How often do pool heaters need to be replaced?

There is no fixed schedule. The Department of Energy says a gas pool heater typically lasts five or more years when it is installed and maintained properly. How long yours lasts depends on water chemistry, how often it runs and how much scale and debris it has dealt with. Replacement makes sense when a major part fails on an older heater or repairs keep coming back.

Who fixes pool heaters in the Phoenix area?

Pool service companies that do equipment work handle most heater repairs. Work on gas lines is different: Arizona's Registrar of Contractors excludes gas lines from its R-6 pool service and repair classification, so a gas piping job needs a contractor licensed for that work. Call the line, describe the heater and the problem, and you are put through to a local pool company. Ask for its ROC license number and check it before work starts.

Pool heater will not heat? Call the free line

One free call at any hour. Say what the pool is doing and where in the Valley you live, and the line puts you through to an independent, locally owned pool company that sees the pool for itself and sets its own price.