I’ve finished the research, so I’m writing the final article now.
Two trades, one appliance
Most KL homeowners find out the hard way that a water heater sits right between two trades. Water flows through it, and electricity heats it.
At KL Plumbing Handbook, we get one question a lot: plumber or electrician for water heater faults? The short answer is that water-side faults go to a plumber, and power or heating faults go to a qualified electrician.
Call the wrong trade and you pay a visit fee for a diagnosis instead of a fix. Some jobs need both, and a few faults could be either.
Below, we sort the common faults into water-side and electrical, cover the jobs that need both trades, and show how to work out who fixes a water heater that’s not heating. For heater faults in general, see the Water Heaters section.
Water-side faults: call a plumber
Call a plumber when the problem is about water getting in, flowing through, or leaking out:
- Leaks at the pipe joints, flexible hoses or valves connected to the heater
- Weak flow through the heater or the shower
- Water dripping from a storage heater’s pressure relief valve
- Pipe problems, such as unsuitable pipe material on the hot side
- Moving or replacing the pipes when a heater is relocated
Flow matters more than most people expect. Rheem Malaysia lists low hot water pressure as the most common complaint with instant heaters, because they need enough flow to switch the heating on. Many Malaysian instant heater spec sheets quote a minimum around 0.2 bar (20 kPa), and some list roughly 2 litres a minute to trigger the flow switch.
A leak from the tank body itself is a different story. Rheem Malaysia notes that storage tank leaks usually come from internal corrosion, pressure build-up or a cracked tank, and that is often a replacement job, not a repair.
Before a plumber touches the heater, switch it off at its switch and the breaker.
Electrical faults: call a qualified electrician
Call a qualified electrician when the problem is about power, heating or safety:
- Tripping the ELCB, RCCB or circuit breaker
- No power, with no light or indicator on the heater
- No heating with good flow and power on
- Burning smell, scorch marks or a hot switch
- Faulty switch or loose wiring
- New circuit or upgraded wiring for a bigger heater
If the water flows well but never gets hot, the culprit is usually the heating element or thermostat. Rheem Malaysia names both as the typical causes of no hot water in storage heaters, and the same logic applies to the controls in an instant unit.
A burning smell or a hot switch is a stop-now sign. Turn the heater off at the breaker and call someone qualified the same day.
Never open a heater casing or work on wiring yourself.
Jobs that need both
Installing, replacing or moving a heater needs a plumber and an electrician, each doing their own part. The table shows who handles what.
| Job | Plumber | Qualified electrician |
|---|---|---|
| Installing a new heater | Mounts the heater, connects pipes, tests for leaks | Connects wiring, switch and earth, checks the circuit |
| Replacing an old heater | Disconnects and reconnects pipes | Disconnects and reconnects power safely |
| Water leaking into the heater | Fixes the leak | Checks the heater is safe to use |
| Moving a heater | Reroutes pipes | Reroutes the power supply |
| Adding a booster pump for the heater | Fits the pump and pipes | Wires the pump |
Agree who does what before the day. Two trades turning up with each assuming the other will test the connection is how small leaks and loose terminals get missed.
The lukewarm water puzzle
Lukewarm water can be either a water-side or an electrical fault, so check the flow first. Three quick checks usually settle who fixes a water heater that’s not heating.
- Check the flow. Turn the shower to full. Is the flow weak? An instant heater may not be getting enough water to switch its heating on properly, or it may be cutting in and out. That points to pressure, a blocked filter or shower head, or the supply, so a plumber is the right start. Our guide on instant versus storage water heaters explains why flow matters.
- Check the setting. Is the temperature knob turned up?
- If flow and setting are fine and the water is still lukewarm, the element or controls are likely faulty. That is electrical.
Try the quick checks before you book anyone. A clogged shower head is a five-minute fix, and it saves a call-out.
Landed house and condo notes
Landed house. Heaters in landed houses are often fed from a roof tank, sometimes through a booster pump. Gravity gives roughly 9.8 kPa for every metre of height, so a tank only 2 metres above the heater delivers about 20 kPa, right at the minimum many instant heaters list. Weak flow may come from the tank height, the pipe size or the pump, which are all plumbing questions. The Water Pressure section covers those.
Condo unit. Most condo bathrooms use instant heaters fed by the building supply. If several units have weak hot showers at the same time, ask building management about the building’s pumps before calling anyone. For work inside your unit, check whether building rules limit contractor hours.
Rented homes. Report heater faults to the landlord or agent in writing. The heater is usually part of the owner’s fittings, so the owner normally arranges the repair unless it was damaged by misuse.
Safety first, whichever trade
Switch the heater off before anyone works on it, and never let anyone bypass the safety trip.
- Switch the heater off at its switch and the breaker before anyone works on it.
- Do not let anyone bypass the ELCB or RCCB to “test” the heater.
- Ask the electrician to confirm the heater is properly earthed.
- Buy heaters that carry the SIRIM label and are approved for sale in Malaysia.
Suruhanjaya Tenaga (the Energy Commission) regulates electrical equipment safety. It covers 34 categories of household electrical products, which must carry the ST-SIRIM label before they can be sold. Suruhanjaya Tenaga has also published a guideline on the design, installation, inspection, testing and maintenance of water heater systems, which a competent electrician should know.
Permits and qualifications
Each trade has its own licence, so ask about both before work starts.
| Trade | What to look for |
|---|---|
| Plumber | An IPA Type A permit from SPAN, needed for work on pipes carrying water from the public mains |
| Electrician | A qualified, registered electrical contractor or competent person registered with Suruhanjaya Tenaga |
SPAN’s IPA Type A permit covers building, connecting, modifying and repairing water pipes and fittings that carry mains water. On the electrical side, Suruhanjaya Tenaga requires contractors to hold a valid certificate of registration before they carry out electrical work.
Our hiring checklist covers how to check both.
When to call a plumber
For the plumber or electrician for water heater question, use this rule. Call a plumber for leaks, weak flow through the heater and the pipe side of any installation or replacement. Call a qualified electrician for tripping, no power, no heating and any wiring.
For a new heater, ask whether the provider covers both trades, or book them separately and agree who does what before the day. If you’re unsure which fault you have, run the three lukewarm checks first, then call the trade they point to.