AquaMAX Hot Water Troubleshooting: Step-By-Step Guide

AquaMAX hot water troubleshooting works best when you know which model range you’re dealing with – since the G-series gas storage units, the single-element electric range and the dual-element Pro-tec models all fail in very different ways.

We’ve built this guide for every single AquaMAX user – find your system right at the start in Step 1, and jump straight to the steps that apply to you. Couldn’t be easier!

About AquaMAX

But first, a little about this great little brand. AquaMAX is one of the more established names in Australian hot water, manufactured by AquaMAX Australia Pty Limited out of Moorabbin, Victoria.

The gas storage range carries a minimum 5-Star energy rating, and AquaMAX was the first Australian brand to pair that efficiency rating with a 10-year warranty, which says something about how confident they are in the build quality.

We see a steady stream of AquaMAX units across Brisbane homes, particularly the G-series gas storage models and the electric range, and on the whole they’re a reliable system that tends to give plenty of warning before a real fault develops … provided the early signs aren’t ignored.

Is your AquaMAX playing up? Start right here:

Step 1: Identify your system

• AquaMAX’s gas storage range includes the G270SS, G340SS and G390SS – all outdoor stainless steel units with a pilot light and burner, distinguished mainly by storage capacity and recovery rate.
• The electric range spans single-element models from 50L to 250L and dual-element Pro-tec models from 80L up to 400L, which run two separate heating elements, one near the base and one near the top, each with its own thermostat.

Knowing which range you’ve got isn’t just academic – it changes which fault is actually likely. The beauty of our AquaMAX hot water system troubleshooting guide is that we’ve got everything covered:

• For gas storage (G270SS/G340SS/G390SS), read Steps 2, 3 and 6.
• For single-element electric, read Steps 2, 4 and 6.
• For dual-element Pro-tec electric, read Steps 2, 5 and 6.
• For G390SS with mixing valve, also read Step 7.

Step 2: No hot water at all

Gas storage: Check the pilot flame through the front access panel. If it’s out, don’t relight it if you smell gas anywhere near floor level, leave the area and call a technician instead.

Electric: Check the isolating switch at the switchboard hasn’t tripped. This is the single most common cause of a fully cold electric AquaMAX, well ahead of any internal fault.

Step 3: Pilot light keeps going out (Gas storage)

If the AquaMAX pilot light keeps going out after relighting, follow the correct sequence rather than repeating a rushed attempt:

• Turn the gas control knob to OFF
• Wait a full five minutes for residual gas to clear – don’t skip this step!
• Turn the knob to PILOT
• Press and hold the reset button
• Ignite the pilot
• Keep holding for 20 to 30 seconds before releasing.

If it stays lit, turn the knob to ON. If it still won’t hold, the thermocouple is the most likely fault.

This is one of the most common AquaMAX gas hot water troubleshooting scenarios on the G-series range, this small sensor confirms the flame is burning and keeps the gas valve open. Wind gusts or an empty LPG cylinder can also cause repeated outages that aren’t a fault at all, so it’s worth ruling those out first.

Step 4: Single-element electric not heating properly

AquaMAX electric hot water troubleshooting for a single-element unit usually comes down to the thermostat or the element itself.

Check the thermostat is set correctly. Most AquaMAX electric models allow adjustment for extra capacity, though hotter settings increase scald risk. If the setting looks right and the water still isn’t heating, the element has likely failed and needs replacement by a licensed technician.

Step 5: Dual-element Pro-tec issues

Pro-tec models heat water with two separate elements and thermostats, one at the base and one near the top of the tank. If you’re only getting a small amount of hot water before it runs cold, the top element is often the one at fault, since it’s the first to be drawn from.

A fully cold tank on a dual-element unit usually points to the isolating switch rather than both elements failing simultaneously, which is uncommon.

Step 6: PTR valve dripping & warranty considerations

A small, occasional drip from the pressure and temperature relief (PTR) valve is normal. But continuous discharge usually means the thermostat isn’t cutting out properly or sediment has built up inside the tank, both of which raise internal pressure beyond what the valve is designed to handle quietly.

Note that AquaMAX’s warranty terms exclude damage caused by certain water chemistries and by tampering with the PTR valve or other safety devices, so a proper inspection matters more than a DIY workaround here.

Step 7: G390SS mixing valve adjustment

The G390SS is the only model in the range fitted with an adjustable water mixing valve, set by a numbered dial. Each increment down from the default position 5 drops the delivered hot water temperature by roughly 5°C.

If your G390SS is delivering water that’s too cool, check this dial before assuming a heating fault; it’s a common oversight after a service or a reset.

When to call an accredited technician

AquaMAX specifies that servicing and warranty repairs should go through their accredited service network, and using unauthorised parts or repairs can affect warranty cover. Thermocouples, heating elements, gas valves and PTR valves all fall into licensed-only territory, both for safety and to keep your warranty intact.

AquaMAX hot water repairs across Brisbane

S&J Hot Water Brisbane installs, services and repairs AquaMAX systems from both our Northside and Southside branches, covering Brisbane, Logan, Moreton Bay, Redland Bay and Ipswich.

AquaMAX has been manufacturing hot water systems in Australia since being established in Moorabbin, Victoria, and we carry that same standard into every Brisbane callout – no matter the problem or if you need a full system replacement.

Our technicians see this range regularly enough to diagnose most faults on sight, rather than working through a generic checklist. So call today for fast, same-day hot water repairs backed by fixed pricing and a genuine workmanship guarantee.