Rheem Hot Water System Not Working: What to Check

There's nothing like a cold shower to remind you how much you rely on your hot water. If you're standing there wondering why your Rheem has suddenly stopped playing ball, you're not alone, and there are a few things worth checking before you pick up the phone.

Rheem is one of the most common hot water brands in Australian homes, across gas, electric, solar and heat pump models, and they're generally very reliable. But any system can hit a snag after a few years, or when the weather, water pressure or power supply throws it a curveball. Below are the checks we run through ourselves, based on Rheem's own fault codes and manuals and a fair bit of hands-on experience.

1. Know which system you've got

First thing, work out what you're dealing with. Rheem makes a few different types:

• Continuous flow (gas)
• Electric storage
• Gas storage
• Solar (with or without a gas or electric booster)
• Heat pumps

They all behave a bit differently, but they share one handy trait: when something goes wrong, most Rheem units show a fault code. So before you panic, have a look at the screen on the unit or the controller. If there's a number flashing, that's your first clue.

2. Look for an error code

A code is good news, because it takes the guessing out of it. A few common ones:

• 11 = ignition failure
• 12 = flame failure
• 14 = overheat
• 79 = fan motor fault

These come straight from the Rheem troubleshooting manual, and on continuous flow models they show up on the controller. If you're on LPG and seeing an 11, it can be as simple as a low bottle, so check that first and restart the unit.

3. Try a restart

Especially on gas models, a restart will often clear a minor hiccup:

• Turn the power off at the wall.
• Wait ten seconds.
• Turn it back on.
• Reopen the hot tap.

If the code comes straight back, don't keep resetting it. That's the unit telling you it needs a proper look.

4. Check the basics: power and gas

If the screen's blank or there's no hot water at all:

• Make sure the unit is plugged in and switched on.
• For solar or electric, check the circuit breaker.
• For gas, check your gas supply hasn't been interrupted.
• For LPG, check the bottle and regulator.

You'd be surprised how many callouts come back to the power or gas supply rather than the unit itself.

5. Continuous flow unit? Check your flow rate

One of the most common continuous flow problems is fluctuating temperature, or no hot water when the tap's barely open. These units need a minimum flow of water to fire up, so if you've got water-saving taps or showerheads you might be sitting under that threshold, especially on a new install.

Try opening the tap fully. If that fixes it, you may need to change the aerator or restrictor on the tap.

6. Solar unit? Check the booster and the weather

If your solar system is running lukewarm or cold, think about the weather first. A run of cloudy or rainy days cuts your solar collection right down. Most systems have a gas or electric booster, so check that:

• The booster is switched on.
• The timer, if you have one, is set correctly.
• You've got enough booster time to cover the day's use.

If the booster's on and the water's still cold, it could be a failed thermostat, element or controller.

7. Heat pump? Listen, and watch the lights

On heat pumps, a flashing light on the control panel is common. It might be nothing more than defrost mode, or it could be a sensor fault. If you can't hear the fan or compressor running, or the light keeps flashing in a set pattern, it's worth a service call. Your owner's guide will explain the specific pattern.

8. Water leaking? Take a closer look

Not every leak is a disaster. On storage tanks, the temperature pressure relief valve (the TPR) is meant to release a little water while the tank heats. But if it's more than a bucket a day, if it's constant, or if water's coming from fittings or joints, it's time to act. A slow hot water leak left too long leads to corrosion or electrical trouble, and we see plenty of "not working" jobs that started as a leak nobody chased up.

9. Check the controller or thermostat setting

If you've got a wall controller in the kitchen or bathroom, make sure the temperature isn't set too low. On electric storage models, the thermostat itself can be faulty or set wrong. If the water's warm but never properly hot, check whether a child-safe or temperature limiter has been switched on.

10. Still stuck? Call a licensed plumber

Sometimes it's beyond a DIY fix, and that's fine. If you've been through the basics and your Rheem's still not working, it needs a licensed plumber to inspect it. We've spent years reading fault codes, testing components and making safe, compliant repairs on Rheem units, from flow sensors to gas valves to thermistors. One thing worth repeating: never push your luck with gas or electrical parts yourself. That's where it gets risky.

How we do it at Fix-It Right

If you've worked through the checks and your Rheem's still not right, that's our cue. We keep it simple: there's $0 call-out, we give you three written quotes so you can pick what suits your budget, and you'll always know the price before we start. If the number's a stretch, Fix-It Now Pay Later gives you 12 months with no interest and no repayments. Every job is backed by our 10-year workmanship guarantee, because the whole idea is to fix it properly the first time. Plumbing fixed for good, not fixed for now.

We look after hot water systems across Melbourne, Geelong, Ballarat and Canberra, from repairs to full replacements. Book online or give us a call and we'll get your Rheem sorted properly.