Some of the most frustrating calls we get at Hot Water System Perth start the same way. It’s usually a cold morning, you’ve just stepped into the shower, and the water is freezing.
We know that sudden feeling of panic. Since we started fixing local systems in 2021, we have seen that many “broken” units actually just need a simple hot water repair.
You might not need a new system at all. Before you worry about the cost of a replacement, there are several safe, easy checks you can do yourself.
We are going to walk you through the exact troubleshooting process our technicians use, starting with the basics and moving to system-specific fixes.
Quick Checks Before Calling for Help
1. Check If It’s Just One Tap
We often see homeowners panic about a total system failure when the issue is actually isolated to a single fixture.
How to test this:
- Turn on the hot water in the kitchen.
- Check the bathroom vanity.
- Test the laundry tap.
If only one outlet is cold: The problem is likely a washer or cartridge in that specific tap, or its isolation valve is closed. Your hot water unit is probably fine.
2. Is the Water Cold or Just Lukewarm?
There is a big difference between “ice cold” and “not quite hot enough.”
Cold water only: This usually means the heating source has failed completely. On a gas unit, the pilot light might be out. On an electric unit, the power supply or element is the likely culprit.
Lukewarm water (The Tempering Valve Check): In Perth, regulations (AS/NZS 3500.4) require a tempering valve to limit bathroom water to 50°C.
- The Symptom: Water is warm but never hot.
- The Cause: These valves often fail after 5-8 years, mixing in too much cold water.
- The Check: If the copper pipe coming out of your tank is extremely hot to the touch, but the water at the tap is cool, your tempering valve is likely the problem, not the tank itself.
3. Check Other Gas Appliances
If you have a gas hot water system, this is the fastest way to rule out a supply issue.
The test:
- Turn on a gas cooktop burner.
- Check if your gas room heater fires up.
If nothing works: You likely have a gas supply interruption. Check if your main gas valve at the meter (usually on the side of the house) is turned 90 degrees to the “off” position. If it is open, contact Alinta Energy or Kleenheat to check for local outages.
Causes by System Type
Electric Storage Hot Water
Most electric systems in WA are reliable workhorses, but they have two common weak points: power supply and the thermostat.
Power supply issues:
- Go to your main switchboard.
- Look for a breaker labelled “Hot Water” or “HWS”.
- If it has tripped to the “OFF” position, flick it back on.
The “Red Button” Reset: Many electric units (like Rheem or Vulcan) have a safety cut-out on the thermostat.
- Turn off the power at the switchboard (Safety First).
- Unscrew the small access cover on the side of the tank.
- Look for a small button (usually red).
- If it has popped out, press it firmly until it clicks.
- Replace the cover and turn the power back on.
Synergy Midday Saver & Timers: If you are on the Synergy Midday Saver plan, remember that “Super Off-Peak” (8.4c per unit) is between 9am and 3pm.
- If your timer is set incorrectly, your water might not heat during the day.
- Check that your timer clock matches the current time, especially after a blackout.
Gas Storage Hot Water
For older units, the pilot light is the most common point of failure. Perth’s coastal winds can sometimes blow these out if the cover is loose.
Pilot light troubleshooting:
- Locate the cover: Most units have a small access panel at the bottom.
- Check the window: Look through the viewing glass. You should see a small blue flame.
- Relighting: Follow the instructions printed on the inside of the door. Usually, this involves holding the control knob down in the “Pilot” position and pressing the igniter button.
Safety Warning: If you smell gas, do not attempt to spark the igniter. Turn the gas off at the meter immediately and call a professional.
Gas Continuous Flow (Instantaneous)
These modern box-on-the-wall units (like Rinnai or Rheem) are essentially computers that heat water. When they fail, they will usually tell you exactly why using a digital error code on the remote controller.
Common Perth Error Codes:
| Error Code | Likely Cause | Action You Can Take |
|---|---|---|
| 11 | No Ignition | Check gas supply is on. Check gas bottle level (LPG). |
| 12 | Flame Failure | Check for dirt/dust on the unit. Windy conditions may have blown it out. |
| 10 | Air Supply Blockage | Look for spider webs or wasp nests in the exhaust flue. |
| 79 | Fan Motor Issue | Often caused by a blockage or strong winds. |
The “Flow Rate” Issue: These units need a minimum water flow (usually around 2-3 litres per minute) to fire up. If you have a water-saving showerhead that restricts flow too much, the heater might not turn on. Try opening the tap further to see if the burner ignites.
Heat Pump Hot Water
Heat pumps are becoming standard in Perth to take advantage of solar PV systems. Brands like iStore or Reclaim are popular here, but they operate differently than standard electric tanks.
Power and airflow:
- Ensure the compressor unit (which looks like an air conditioner) has clear airflow.
- Remove any weeds or boxes stored up against the fan unit.
Noise & Timing: Modern units are quiet (45-55dB), but if yours is making a loud grinding noise, the fan bearing may have failed.
- Check your controller settings. If you have accidentally set the “timer” to run only at 3am, you might run out of hot water by the evening.
Solar Hot Water
In Perth, we get plenty of sun, but you still need your booster during winter (June-August) or on overcast days.
The Booster Switch:
- Electric Boost: Look for a switch labelled “Solar Booster” or “Water Heater” on your wall (usually in the kitchen or laundry) or in the meter box. It must be ON during cloudy weather.
- Gas Boost: This works automatically. If water is cold, check the gas supply steps mentioned earlier.
Winter Performance: If your water is lukewarm in July, it is not broken; the sun just isn’t strong enough. You must manually activate the booster to top up the temperature.
Temporary Solutions
If you need to wait for a part or a replacement, here is how to get by.
Safe Boiling: Use a kettle to fill a bathroom basin for a sponge bath. Always put cold water in the basin first, then add the boiling water. This prevents scalding and damage to your basin.
Local Facilities:
- Gyms: Chains like Jetts or Anytime Fitness have 24/7 showers.
- Public Pools: Facilities like Beatty Park or HBF Stadium offer casual entry fees that include shower access.
When to Call a Professional
Sometimes, a DIY fix isn’t safe or possible.
Call Immediately If:
- You smell gas.
- Water is pouring out of the bottom of the unit (major tank failure).
- You see scorch marks around electrical switches.
Repair vs. Replacement Costs (2025 Estimates)
Knowing the potential costs can help you decide.
| Service Type | Estimated Cost (Perth Metro) |
|---|---|
| Minor Repair (Thermocouple, Valve) | $180 - $350 |
| Major Repair (PCB Board, Compressor) | $500 - $900+ |
| Electric Replacement (Supply & Install) | $1,600 - $2,900 |
| Gas 5-Star Replacement | $1,800 - $3,800 |
| Heat Pump Replacement | $3,500 - $4,995 (Pre-Rebate) |
What to Tell Us:
When you call, having this info ready saves time:
- Brand: (e.g., Rheem, Rinnai, Dux).
- Model Number: Usually found on a sticker on the side of the tank.
- Date of Manufacture: Also on the sticker.
- Symptom: “Cold water” vs “Lukewarm water.”
Prevention Tips
Anode Replacement (Crucial for Perth)
Perth water is “hard” (mineral-rich), especially in the northern suburbs. This eats through steel tanks.
- The Fix: Your system has a “sacrificial anode” inside.
- The Schedule: In Perth, we recommend checking this every 3-4 years. If you wait 5+ years, the tank may have already started to rust.
Regular Flushing
Every 6 months, locate the Pressure Relief Valve (PRV) near the top of the tank.
- Lift the lever gently for 5 seconds.
- This flushes out grit and calcium build-up that can jam the valve open.
Our Emergency Service
At Hot Water System Perth, we know that a cold shower is a miserable way to start the day.
Same-day response: We prioritize “no hot water” calls. If you call us in the morning, we aim to be there that afternoon.
Local expertise: We carry parts for the systems most common in WA homes, including Rheem, Rinnai, and iStore.
Honest advice: If your system is 15 years old and leaking, we will tell you if a repair is throwing good money after bad. We believe in fixing what can be fixed and replacing only when necessary.
Don’t wait for the problem to fix itself. Call us for emergency hot water service and get your hot water running again today.
