Pool Heater Not Firing Up? Start Here

If your pool heater will not fire, starts and stops, or shows an error code, the cause is not always obvious from the outside. A fault in the controls, water flow, ignition or a safety device can stop the heater before it warms the pool.

For gas pool heaters, do not remove panels or try to force the heater to start. If you smell gas, leave the area and call Triple Zero (000) for Fire and Rescue NSW. Read the NSW Government gas-safety guidance.

Three useful details to have ready

You do not need to diagnose the heater yourself. These details help us understand the problem before we arrive:

what the heater does when you ask it to heat the pool — no response, an error code, ignition followed by a shutdown, or running without warming the water;
the brand and model, if you can see it without opening the unit; and
a photo of the controller display or the exact error code, if one appears.

Leave the repair work to a qualified technician. The fault code or symptom is a starting point, not a diagnosis on its own.

Why a pool heater may not fire up

A pool heater can fail to start for different reasons. Water-flow and pressure signals, ignition and flame-sensing components, control faults, safety devices and service-related build-up can all stop a gas heater from running normally. Heat pumps can also display a fault code or stop when a control or flow issue needs attention.

The right repair depends on the heater and the fault found on site. That is why a fault is checked rather than guessed from a code alone.

A Hurlcon pool-heater service in Gladesville

On a Hurlcon gas pool-heater service in Gladesville, we found heavy soot build-up in the heat exchanger and burner. We cleaned all components, checked gas pressures and safety devices, then ran the heater for 15 minutes.

It is a useful reminder that not every problem is visible from outside the heater. A unit that will not fire, runs poorly or keeps cutting out needs the fault checked before a repair is recommended.

Shane, from the Sydney Pool and Gas Heating team, is on the tools for gas pool-heater work. Gas work is carried out under NSW licence 498373C.

When it is time to book a pool-heater repair

Book a visit if the heater will not start, repeatedly shuts down, shows an error code you cannot clear, or runs without heating the pool as it should. We service and repair all major gas pool-heater brands — Astral, Hayward, Hurlcon and Pentair among them — as well as pool heat pumps.

For service and repair options, including the current starting prices, see our pool heater service and repair in Sydney. If your heater needs attention, that page has the booking details.

Pool-heater fault questions

Can a pool heater that will not fire up be repaired?
Often, yes. The repair depends on what is stopping it from operating, so the heater needs to be checked before a repair is recommended.

Why does my pool heater start and then cut out?
A shutdown can be caused by a control, flow, ignition or safety-related issue. The symptom helps narrow the check, but it does not identify the part by itself.

Should I keep resetting my pool heater?
No. If the heater keeps stopping or showing the same code, leave it off and arrange a check rather than repeatedly trying to restart it.

What should I do if I smell gas near the pool heater?
Leave the area and call Triple Zero (000) for Fire and Rescue NSW. Do not use flames, switches or the heater while gas may be present. Follow the NSW Government gas-safety guidance.

Need help with a pool heater that will not fire?

Call Sydney Pool and Gas Heating. Tell us what the heater is doing, any error code on the display and the brand if you know it, and we will arrange a service visit.

0422 302 722