What causes water heater problems?
Malaysian homes mostly use two kinds of electric heater: an instant water heater that heats water as it flows, and a storage water heater that heats and holds a tank. Both can develop the same broad faults. Water heaters are the one area of our home plumbing guide where electrical safety comes first.
- Heating element wear or corrosion, which causes no heat, lukewarm water or tripping
- Moisture getting into the casing, switch or terminals
- Wiring faults at the heater, switch or circuit
- Leaking joints and flexible hoses on the hot and cold connections
- Low flow, which stops an instant heater from heating properly
- Tank corrosion in older storage heaters
- A faulty pressure relief valve on a storage heater
What will you notice?
| Symptom | Likely area | Guide |
|---|---|---|
| Trips the breaker | Electrical | Heater keeps tripping |
| No hot water | Electrical or flow | Plumber or electrician? |
| Lukewarm water | Flow first, then element | Plumber or electrician? |
| Leak at pipes | Plumbing | Hot water pipe leaks |
| Leak from the heater itself | Heater fault | Repair or replace? |
| Weak flow through the heater | Flow and pressure | Water Pressure |
What can you safely check yourself?
- Switch off the heater at its switch if it trips, leaks or smells of burning.
- Check the breaker. If it tripped, reset it once with the heater switched off. If it trips again with the heater off, the fault is elsewhere and needs an electrician.
- Look for water at the pipes, casing and switch, without touching the heater.
- Check the flow. Clean the shower head and check valves are fully open.
- Check the setting on the temperature knob.
Never open the casing, touch wiring or bypass the ELCB or RCCB.
Landed house
Heaters upstairs may be fed by gravity from a roof tank, which can mean low flow. A booster pump can help an instant heater work properly, but it also adds pressure to joints. The Water Pumps section covers pumps.
Condo unit
Most condo bathrooms use instant heaters. If several units have weak hot showers, the building supply may be the cause. Check house rules before changing a heater that needs new wiring.
What does a repair involve?
- Element or thermostat replacement by a qualified person
- Pipe joint or hose replacement by a plumber, with heat-rated material
- Replacing the heater when the tank is corroded, the casing is damaged or faults keep returning
Choosing a replacement? Our guide to instant vs storage water heaters compares flow, space, number of bathrooms and booster pump use. Buy a heater with the SIRIM label. Electrical equipment safety is regulated by Suruhanjaya Tenaga (the Energy Commission).
The partner’s published heater prices, with source and date, are listed further down this page.
When should you call a plumber?
Call a plumber for leaks, weak flow and the pipe side of a new installation. Call a qualified electrician for tripping, no power, no heating and wiring. If water has got into the heater, you need both: the plumber to fix the leak, and the electrician to confirm the heater is safe before it is used again.
