No Hot Water? Troubleshooting Guide for Perth Homeowners
Step-by-step guide when your hot water stops working. Common causes, what to check before calling a plumber, and when you need professional help.
Waking up to a freezing shower is a rough start to any morning. You know how reliable Perth summers are? We find that hot water systems often behave like the exact opposite, and they usually decide to fail on the coldest morning of the year.
Most homeowners assume a cold shower means a total system replacement is imminent.
We have found that nearly 40% of the service calls we attend in the Perth Metro area are simple issues that could have been resolved without a technician. Before you worry about the cost of a new unit, let’s walk through the exact diagnostic process our team uses to identify the fault. If you do need professional help, our hot water repair service covers all system types across Perth.
First Steps: Don’t Panic
Complete hot water loss is usually caused by one of a few common issues. Many can be quickly diagnosed, and some you can resolve yourself.
Important safety note: Never attempt repairs on gas systems unless you’re confident with basic procedures. If you smell gas, leave the area and call your gas supplier immediately.
Electric System Troubleshooting
Check 1: Circuit Breaker
The most common cause of electric hot water failure is a tripped circuit breaker.
We respond to dozens of calls annually where the only “repair” needed is flipping a switch.
- Find your electrical switchboard
- Look for a switch labelled “Hot Water” or “HWS”
- If it’s in the off or middle position, switch it fully off then back on
- Wait 30-60 minutes for water to heat
If the breaker trips again, don’t keep resetting it - this indicates a fault requiring professional attention.
Repeated tripping often signals a “dead short” in the element. This usually happens when the copper sheathing splits due to corrosion.
Check 2: Off-Peak Timer
If your system uses off-peak electricity, hot water only heats during certain hours (usually overnight). If you’ve used more than usual, the tank may be empty until the next heating period.
Synergy’s standard “time of use” tariffs in WA often restrict heating to between 9:00 AM and 3:00 PM for solar soak plans, or overnight for traditional off-peak.
Check your meter box for a mechanical timer. The clock face might be out of sync if there was a recent suburb-wide power outage.
Check 3: Temperature Setting
Some thermostats can be accidentally adjusted. If you get lukewarm water, the thermostat may be set too low.
We also suggest checking for an “Over-Temperature Cut-Out” reset button.
Many modern electric tanks (like Rheem or Dux models) have a small red or black reset button on the thermostat block under the access cover.
Warning: Only check this if you are comfortable turning off the mains power first.
Gas System Troubleshooting
Check 1: Pilot Light
Most gas storage systems have a pilot light that must stay lit:
- Find the viewing window on your unit
- Look for a small blue flame
- If no flame visible, the pilot has gone out
To relight (basic systems):
- Turn gas control to “Pilot”
- Hold down while pressing igniter
- Once lit, continue holding for 30 seconds
- Release and turn control to “On”
If the pilot won’t stay lit, professional service is needed.
The culprit is almost always the thermocouple. This small safety sensor detects heat; if it fails (usually every 4-5 years), it shuts off the gas to prevent leaks.
Check 2: Gas Supply
Verify gas is reaching your hot water:
- Check other gas appliances are working
- Ensure the gas isolation valve near the unit is open
- Check if you’ve run out of gas (LPG systems)
Check 3: Continuous Flow Error Codes
Instantaneous gas units display error codes when problems occur. Check your manual for code meanings. Common issues include insufficient gas pressure or blocked flue.
We have compiled the most frequent codes we see in Perth for major brands like Rinnai and Rheem below.
| Error Code | Common Meaning | Likely Cause |
|---|---|---|
| Code 11 | No Ignition | No gas supply or faulty igniter. |
| Code 12 | Flame Failure | Flame lights but goes out (dirty flame rod). |
| Code 79 | Fan Motor Current | Blocked flue or fan failure. |
Heat Pump Troubleshooting
Check 1: Power Supply
Like electric systems, check the circuit breaker first.
Heat pumps contain sensitive electronics. They are more susceptible to power surges during Perth’s summer electrical storms than traditional tanks.
Check 2: Outdoor Unit
The external heat pump unit needs airflow:
- Check for debris blocking the unit
- Ensure the fan is running when heating
- Listen for unusual noises
We often find units choked by overgrown vegetation.
A heat pump works like a reverse air conditioner. If leaves or bushes block the evaporator coils, efficiency drops by up to 30%, and the unit may shut down to protect the compressor.
Check 3: Boost Mode
If ambient temperature is very cold, the heat pump may struggle. Many units have a “boost” button that activates backup electric heating temporarily.
Perth winter nights can drop to 2°C or 3°C. Older heat pumps struggle to extract heat from air this cold and rely heavily on the electric booster element to bridge the gap.
Solar System Troubleshooting
Check 1: Booster
Solar systems have electric or gas boosters for cloudy days. Check the booster is functioning using the relevant checks above.
We cannot stress this enough: you must manually turn this on during winter.
Many homeowners forget that the “Solar HWS” switch in the switchboard is often separate from the “Booster” switch, which is frequently located on a wall in the laundry or kitchen.
Check 2: Circulation
For pump-based systems, check if the circulation pump is running during sunny periods.
Place a hand (carefully) on the pipe leading to the roof panels. It should vibrate slightly and feel warm during the day. If the pipe is cold at 1:00 PM, your circulator pump has likely failed.
When to Call a Professional
Call immediately if:
- You smell gas
- Water is leaking from the tank
- Electrical burning smell
- System makes concerning noises
Schedule a service if:
- Basic troubleshooting doesn’t help
- Problem recurs after temporary fix
- System is behaving erratically
- You’re unsure about any step
Emergency Response
For complete hot water failure in Perth Metro, we offer same-day response. Call before noon and we’ll have a technician to you the same day.
Our vans carry spare parts for the most common WA systems, including Rheem Stellar, Rinnai Infinity, and Dux Proflo units.
Preventing Future Problems
Regular maintenance prevents many hot water failures:
- Annual inspection of safety valves
- Anode replacement (storage tanks)
- Pilot assembly cleaning (gas)
- Filter cleaning (heat pumps)
The single biggest killer of hot water tanks in Perth is our hard water.
We see calcium carbonate buildup destroy tanks in as little as 5 years if the sacrificial anode is not replaced.
Recommended Maintenance Schedule
| Component | Interval | Why It Matters |
|---|---|---|
| PTR Valve | Every 6 Months | Pull the lever to ensure it doesn’t seize. Prevents tank explosion. |
| Sacrificial Anode | Every 3-4 Years | Perth’s water eats this rod instead of your tank walls. |
| Tempering Valve | Every 5 Years | Ensures water stays at a safe 50°C to prevent scalding. |
Contact us to discuss a maintenance schedule that protects your hot water investment.
Have Questions About Your Hot Water System?
Our team is ready to help with expert advice and professional service.