- 300+ five-star reviews · VBA accredited plumbers
- Charged by the job, not by the hour, you approve the price before any work starts
Call 1800 571 216: 24/7 · Book online
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Why Melbourne calls OnCall for continuous flow
- 24 hours, 7 days: including weekends and public holidays
- More than 15 years of emergency plumbing across Melbourne
- 300+ five-star reviews on Google
- VBA accredited, licensed and insured plumbers
- All makes and models of continuous flow (instantaneous) units
- Job-based pricing: approved by you before work starts
What customers say about OnCall
"Aiden was very professional and on time to the job. Got it done and dusted faster than I expected."
Eren, Google review
"He turned up on time, went above and beyond, showed and explained everything and got the job done …"
Nancy Tayba, Google review
How a continuous flow system works, and why that matters
There's no tank. When you open a hot tap, the unit senses water flowing, lights its burner (or switches on its elements, on electric models), and heats the water as it passes through. Turn the tap off and it shuts down.
That design explains most faults. The unit needs enough water flow to switch on, enough gas to heat at full demand, and power to run its electronics and fan. Lose any of those and you lose hot water. It also means a gas continuous flow unit won't work during a power outage, which catches plenty of people out.
Quick checks before you call
- Is there an error code? Write it down or take a photo of the controller. It saves time on the phone and on site.
- Is the unit getting power? Check the power point or isolation switch near the unit, and the switchboard.
- Is the gas on? Try the stove. If no gas appliance works, the issue may be the supply. Smell gas? Isolate the gas at the meter and call us.
- Try one hot tap, fully open. If hot water comes through at full flow but not at a trickle, it's likely a flow issue rather than a failed unit.
- Check the controller temperature setting, in case it's been turned down.
Continuous flow hot water error codes
Error codes are the unit's way of telling you what it thinks has gone wrong: an ignition failure, a flame failure, an overheating sensor, a fan fault, a water flow problem. The catch is that every brand uses different codes, and the same number can mean different things on different models.
Most manuals allow one reset by switching the unit off and back on. If the code comes back, leave it and call. Repeated resets won't fix the underlying fault. For brand-specific help, see Rinnai, Rheem, Bosch or Thermann hot water repairs.
Continuous flow not heating
If the unit's quiet, or the water starts hot then goes cold, these are the usual causes:
- Flow too low to trigger the unit. Every continuous flow system has a minimum flow rate. Low-flow showerheads, a tap barely open, a mixer set mostly to cold, or a blocked inlet filter can all keep it from firing.
- Ignition faults. A worn igniter, a dirty flame sensor or a burner problem stops it lighting or keeps it from staying lit.
- Not enough gas. If the gas supply can't keep up when the cooktop and heating are also running, the unit may cut out or run lukewarm.
- Scale in the heat exchanger. Over time, mineral build-up reduces heating and can trigger overheating faults.
- Frost damage. Units in exposed spots can be damaged in a Melbourne cold snap, especially if the power was off and frost protection couldn't run.
- Fan or sensor faults that stop the unit running safely.
Call 1800 571 216: 24/7 · 300+ five-star reviews · Price approved before work starts
How we fix it: assess, explain, approve, fix
Assess. Your plumber reads the fault history where the unit stores it, checks gas supply, ignition, burner, flow sensor, fan and filters, and finds the cause behind the code.
Explain. You'll hear what the code meant, what's actually failed, and whether it's likely to happen again.
Approve. You get a clear price and your options. Nothing happens until you say yes.
Fix. We repair the fault, then run the unit at different flow rates and test every hot tap and the temperature control before we leave.
Instantaneous hot water repairs we carry out
- Ignition, igniter and flame sensor faults
- Burner and gas valve problems
- Water flow sensor faults and blocked inlet filters
- Fan faults
- Temperature controller and sensor faults
- Heat exchanger scale and overheating faults
- Frost-damaged pipework and fittings
- Leaks from the unit and its connections
- Lukewarm water when two taps run at once
If a gas supply issue is outside the unit itself, we'll tell you what's going on and what needs to happen next.
Continuous flow installation and replacement
Continuous flow units usually last a good while, but heat exchangers can corrode or crack, and some faults on older units cost more to fix than they're worth. If that's where yours is at, we'll show you why and let you decide. See hot water system replacement for what's involved in swapping a failed unit.
Planning to switch from a storage tank to continuous flow, or adding one to a renovation? That's a planned job covered on our hot water system installation page.
Pricing: what to expect
We charge by the job, not by the hour. Your plumber diagnoses the unit on site and gives you a clear price before any work starts.
What moves the price:
- the fault, and the part needed
- the brand and model, and whether the part is in stock
- whether scale or frost damage has affected other components
- access, units mounted high on a wall or in a tight side passage take more work
No work starts without your approval. See hot water repair cost for more.
How it works
- Call or book online. Phone 1800 571 216 at any hour, or book online. Tell us the brand and the error code if you have one.
- Advice and a plumber on the way. We'll suggest any safe checks and send ETA updates.
- Read the fault. Your plumber tracks down what's behind the code and gives you a clear price.
- You approve, we fix. Once you say yes, we repair and test the unit.
- Know what's next. If the unit needs a service, or the gas supply needs looking at, we'll tell you.
Continuous flow questions
What does the error code on my continuous flow unit mean?
It depends on the brand and model, because codes aren't standard. Note it down and tell us when you call; it helps us arrive prepared.
Why is my continuous flow hot water lukewarm?
Often the flow is too low for the unit, or the gas supply can't keep up when other appliances run. Scale in the heat exchanger and sensor faults are other common causes.
Why do I have no hot water during a power outage?
Continuous flow units need power for their ignition, fan and controls, so they stop working when the power's out, even on gas.
Can I reset the unit myself?
One reset by switching it off and on is usually fine. If the code comes back, leave it and call.
Do you repair all brands?
Yes, all makes and models of continuous flow, gas and electric.
Can you fix it today?
Often, yes. We try to fit in same-day repairs across most Melbourne suburbs. Some brand-specific parts need ordering, and if so we'll give you a realistic timeframe.
How much does a continuous flow repair cost?
It depends on the fault and the part. You'll get one job price on site, and nothing goes ahead until you've approved it.
Can a continuous flow unit freeze in Melbourne?
Units in exposed spots can be damaged in a cold snap, particularly if the power was off. If yours stops working after a frosty night, check for leaks and call.
Error code and no hot water? Let's sort it.
A licensed OnCall plumber can read the fault, explain it, price it, and, once you say yes, fix it.
Call 1800 571 216: 24/7 · Book online
300+ five-star reviews · VBA accredited · Price approved before work starts
What happens next: we'll confirm your details, give you pre-arrival advice if you need it, and send a plumber. You'll get ETA updates on the way.