Pool Heater Not Heating? A South Florida Owner's Field Guide

A homeowner in Coral Gables called us the first cold morning of the year: 58 degrees outside, a pool party that afternoon, and a heat pump that had been running since dawn without moving the water past 71. By the time we arrived the cause was textbook for this market — a slow refrigerant leak at a vibration-fatigued fitting that had bled the charge over a season. We found it, repaired it, recharged under EPA 608, and the pool hit 84 by evening. That single call captures almost everything that goes wrong with pool heaters in South Florida.

Pool heaters are the one piece of equipment owners forget about until the temperature drops — and in Miami-Dade, Broward, and Palm Beach that means everyone discovers the problem on the same January morning. Here's how to tell what's actually wrong, and what you can safely check before you book a pool heater repair.

First, know which heater you have

South Florida pools fall into two camps, and they fail in completely different ways.

Heat pumps dominate residential pools here. Pentair UltraTemp, Hayward HeatPro, AquaCal, and Gulfstream units pull warmth out of our already-warm air, which makes them cheap to run all season — but they heat slowly and depend on a clean refrigerant circuit, a working fan, and a titanium coil.

Gas heaters — Pentair MasterTemp, Hayward Universal H-Series, Raypak Digital — heat fast, so they're the go-to for spas and quick on-demand heat. Many luxury homes run a heat pump on the pool and a gas heater on the spa. The two need different diagnostics, so the first question we ask is always: gas or heat pump?

When a gas heater won't ignite

This is the most common gas call. You hear the heater click and try to light, then it locks out. On a Pentair MasterTemp that's usually an E05 ignition lockout; on a Hayward Universal H-Series it reads IF (ignition failure).

Nine times out of ten the part at fault is small: a flame sensor crusted over so it can't prove flame, a weak hot-surface igniter, or a gas valve that isn't opening. An owner can safely check two things first — confirm the gas supply valve is open and the propane tank (if you're on LP) isn't empty, and make sure the filter is clean so the pressure switch sees flow. Beyond that, ignition components carry line voltage and gas, so the diagnosis belongs to a tech. We clean or replace the flame sensor, ohm-test the igniter, and verify gas pressure — and we keep these parts on the truck, so most ignition calls finish on the first visit.

When a heat pump runs but won't warm the water

If your heat pump runs for hours and the water barely moves, the most likely culprit is a low refrigerant charge from a small leak, a failing reversing valve, or a fan that's barely turning. A starved titanium coil just churns ambient air without transferring heat.

Here's the important part: refrigerant work is not a DIY or handyman job. Sealed-system repair on a heat pump requires EPA Section 608 certification — we hold Universal — and recovering, leak-checking, and recharging correctly is what makes the repair last instead of leaking out again in three months. If the titanium coil is still intact, a leak repair and recharge brings the unit right back. Only if the coil itself is breached do we talk about replacing the exchanger.

The salt-air and chemistry problem

This is the South Florida tax on pool ownership. The same coastal air that makes Fisher Island and Boca beautiful is steadily corroding your heater, and pool chemistry finishes the job from the inside.

Gas heaters suffer worst. A bare-copper or cupronickel heat exchanger erodes fast when water chemistry drifts — low pH, high chlorine, or a salt chlorinator running acidic turns the water aggressive and eats the core. You'll see green copper salts crusting around the unit, then eventually a leak that drips onto the burner tray and causes rumbling or soot. Heat pumps last longer on titanium coils but still lose cabinets and electronics to salt aerosol.

The defense is boring but it works: keep pH at 7.4-7.6 and alkalinity in range, rinse the cabinet seasonally if you're near the water, and have the heater serviced once a year. The difference between a $300 pressure-switch repair and a $2,800 exchanger replacement is almost always how early someone catches the corrosion.

What an owner can check before calling

• Filter and flow. A dirty filter or a variable-speed pump set too low for heat mode will trip the pressure switch and stop a gas heater cold. Clean the filter and confirm the pump is running at heat speed.
• Valves. Make sure the gas valve is open and the water diverter valves are set to send flow through the heater.
• The error code. Photograph it before you reset anything — Pentair E05/E06, Hayward LO/IF/HS, or a Raypak code tells us exactly where to start.
• Don't open the cabinet. Gas, line voltage, and sealed refrigerant are all behind that panel. The reading is worth more to us than a guess.

When to call us

If you've checked flow, valves, and the filter and the heater still won't fire or won't warm the water, the next step is a diagnostic. We charge a flat $59 diagnostic — credited to your repair when you approve it, with no separate fee stacked on top. We service every major brand used in South Florida: Pentair, Hayward, Raypak, Jandy/Zodiac, AquaCal, and Gulfstream, gas and heat-pump alike.

If your luxury wellness setup runs deeper than the pool, we also handle the rest of it — see our cold plunge and ice bath repair for chiller and temperature-control work.

Call Berne Appliance Repair at (754) 345-4515. Most days we can have a tech at your door within hours — and before your next cold snap, not after it.