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Hot water installation in Victoria covers two regulated trades. The plumbing side (water connections, tempering valves, pressure-relief discharge) is licensed plumbing work. The gas side (gas connection, flue, ignition) is licensed Type A gasfitter work. Many Melbourne hot water repairs need both. An unlicensed install voids your home insurance and the manufacturer's warranty — and at sale time, an unsigned hot water unit shows up in the section-32 inspection and complicates settlement. Prime Plumbing & Gasfitting holds both licences, so one tradesperson handles the whole job and lodges one Compliance Certificate covering all the work.
Water connections, hot-and-cold lines, tempering valves and pressure-relief valve discharge lines all comply with AS/NZS 3500. The relief valve discharge needs a clear, visible run to a safe location — a relief valve plumbed to a hidden location can flood a wall cavity if it activates, which is a common Melbourne hot water failure mode that gets missed at inspection.
Gas connection, regulator, flue, clearances and pressure testing all comply with AS/NZS 5601. Gas line sizing matters for continuous-flow units — many older Melbourne homes have a 15mm gas line that cannot supply the peak demand of a modern Rinnai Infinity 26, leading to flame-out under load. Prime Plumbing & Gasfitting sizes correctly upfront rather than installing a unit that under-performs at peak.
Plumbing work above the threshold gets a BPC Compliance Certificate; gas work gets a Certificate of Compliance lodged with Energy Safe Victoria. You receive digital copies the same day. Insurers, real-estate agents and conveyancers recognise these as the records of compliant install — they protect your warranty, insurance position and resale outcome.
On the booking call we ask the unit make, model and age, and what is happening — no hot water at all, intermittent, water lukewarm, leak visible, error code on the panel. From this we can usually predict the likely repair vs replace path and quote a starting fixed price before we arrive.
On arrival we test gas pressure (where applicable), water pressure, electrical supply (heat pumps and electric storage), the unit's diagnostics, and the condition of the connection points. For storage tanks we check the anode, the relief valve and the discharge line. The diagnosis is shared with the homeowner — what is failing, why, and what the options are.
Where repair is genuinely the cheaper long-term option, we quote it. Where replacement makes more sense, we quote like-for-like AND the rebate-eligible upgrade path (heat pump, where conditions support it). The homeowner sees the math and chooses. Prime Plumbing & Gasfitting does not push heat pumps where the property cannot support one — narrow side access, no electrical capacity, no suitable outdoor placement all rule them out.
For replacements: drain-down, disconnect, remove old unit, install new, connect water and gas (or electrical for heat pumps), commission, test for leaks, set tempering valve to 50°C at fixtures (Victorian Plumbing Regulations requirement). For repairs: targeted part replacement, system test, leak check.
Plumbing and gas Compliance Certificates lodged the same day. For heat pump installs, rebate paperwork (Victorian Energy Upgrades) is prepared and submitted on the homeowner's behalf where the unit qualifies. The certificate, the receipt and the warranty card go to the homeowner as a single PDF pack — useful at insurance renewal and at sale.
The information you collect before booking determines how accurate our quote is and how quickly we can complete the work on the day. The four steps below cover the common preparation tasks.
The data plate on the unit (usually a sticker on the side or near the gas connection) shows make, model number, and serial. The serial usually encodes the manufacture year. Take a photo of the data plate and send it with your booking — we can pre-source matching repair parts on site, which avoids a second visit.
Continuous-flow units flash an error code on the temperature controller when they shut down. Codes vary by brand but most translate to specific failure modes — flame failure (low gas, blocked flue), water flow sensor, ignition lockout, overheating shutdown. Note the code on your booking; it shortcuts diagnosis significantly.
If the unit is in a side passage or a roof cavity, clear pot plants, garden tools, washing baskets and any obstructions before we arrive. Heat pump replacements need clearance for the outdoor unit footprint plus 600mm clearance to the wall and the roof eave for airflow.
If you had recent plumbing or gas work near the hot water unit, tell us. Sometimes a hot water failure shortly after another job points to disturbed connections or a related installation defect rather than the unit itself failing. Saves time on diagnosis.
Like-for-like gas storage replacement is at the cheaper end. Continuous-flow gas replacement is mid-range. Heat pump replacement is highest upfront but offsets via Victorian Energy Upgrades rebates and lower running cost. Prime Plumbing & Gasfitting quotes a fixed price for each option after seeing the existing unit and connection conditions — there are no surprise install charges on the day.
Under 8 years and a non-tank failure (thermocouple, valve, element), repair is usually the better economic choice. Over 12 years OR any tank leak (rusty water, water under the unit, corrosion), replacement is the better choice — the next failure usually follows soon after. Between 8 and 12 years it depends on what failed and how aggressive the water in your suburb is on anode rods. We give the honest call on the day.
The Victorian Energy Upgrades program currently subsidises heat pump installs that replace a gas or electric system, when the new unit meets efficiency thresholds. Eligibility depends on property type and the existing system. Prime Plumbing & Gasfitting checks eligibility before quoting and prepares the rebate paperwork; the rebate is applied at point of sale where the install qualifies, so the price you see already includes it.
Like-for-like gas storage in a standard side-passage location typically completes in a half-day. Continuous-flow replacement is similar. Heat pump installs typically run a full day because of the outdoor unit positioning, electrical work and rebate paperwork. We quote the time on the booking call so you can plan.
Most often: undersized gas line. A modern Rinnai Infinity 26 needs more gas flow than a 15mm line can supply at peak. The unit ignites, runs for a few minutes, then trips out when demand exceeds supply. Other causes: blocked flue, low gas pressure at the meter, or scaling on the heat exchanger. Prime Plumbing & Gasfitting checks gas pressure on every continuous-flow callout.
A tempering valve mixes hot and cold to deliver bath, basin and shower water at 50°C maximum (50°C is mandatory for new installs in Victoria for scald prevention). Healthcare, childcare and aged-care facilities have stricter requirements (45°C, with annual testing). On a domestic install Prime Plumbing & Gasfitting fits a tempering valve as standard — required by AS/NZS 3500 and Victorian Plumbing Regulations.
Storage tanks: 8-12 years for entry-level mild-steel tanks, 10-15 years for stainless or vitreous-enamel-lined tanks with a maintained anode rod. Continuous-flow gas: 12-18 years if descaled annually. Heat pumps: 12-15 years with annual service. Anode rod replacement at year 5 on a storage tank can extend life by 3-5 years and is much cheaper than replacement.
Where the existing unit type can be matched with stock at our supplier and the install conditions are straightforward, yes. Where the unit needs a non-standard part (older brand, unusual size, custom flue) we usually book in for the next available day. We are honest on the booking call about timing — we do not promise same-day if it is going to mean cutting corners on the install.
Most hot water systems have a lifespan of 8–15 years depending on usage and water quality.
Signs it may be time for hot water system replacement:
Replacing an old hot water system before total failure prevents water damage and disruption.
We remove and dispose of old units safely and install the replacement system with updated valves and safety components where required.
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Not every failure requires a full replacement. Common hot water system repair issues include:
No hot water this morning, the unit running cold within a few minutes, water rusty at the tap, a slow drip from the relief valve, or a unit older than 10 years that is starting to fail? we handle hot water repair, replacement and new installation across Melbourne's east, south-east, inner-east and bayside suburbs. We are licensed for plumbing AND for gas, so the same trade can swap a gas storage unit, recondition a continuous-flow heater, or commission a heat pump — all with Compliance Certificate lodged the same day.
