🛠️ Detailed Step-by-Step Procedure for Storage Water Heater Installation

1️⃣ Pre-Installation Preparation

1.1 Site Inspection

• Visit the installation site to assess:

  • Wall strength and type (concrete, hollow block, etc.)

  • Location accessibility for future servicing.

  • Clearance space above and around heater (min. 300 mm recommended).

  • Ceiling height and door opening space.

  • Nearby cold water line, hot water outlet, and electrical point.

• Confirm with the owner the exact heater location (above door / wall corner / ceiling mount).

1.2 Safety and Isolation

• Turn off main water supply.

• Turn off main power isolator (to avoid electrocution risk).

• Ensure area is dry and safe to work.

• Use ladder with stable footing and safety harness if working above 2.4 m.

1.3 Tools & Materials Required

Tools:

• Rotary hammer drill & masonry bits

• Spanners, adjustable wrench, pipe wrench

• Screwdrivers, voltage tester

• PTFE/Teflon tape, pipe cutter

• Water level, measuring tape, marker

• Ladder, safety gloves, goggles

Materials:

• Storage water heater unit

• Mounting bracket & bolts

• Expansion anchors / Fischer bolts

• SS braided hoses or copper pipes

• Stop valve, check valve, pressure relief valve

• Non-return valve, drain pipe

• Electrical cable (heat-resistant, 2.5 mm² or 4 mm² depending on load)

• 20 A isolator switch with neon indicator

• PVC conduit / flexible wiring

• Silicone sealant

2️⃣ Mounting the Heater

2.1 Marking and Drilling

• Position heater on wall temporarily to mark mounting holes (use level).

• Ensure the inlet/outlet orientation matches the plumbing direction.

• Drill holes with the correct size bit (usually Ø10–12 mm for expansion bolts).

• Clean debris from holes.

2.2 Bracket & Bolt Fixing

• Insert wall plugs or expansion anchors.

• Secure the mounting bracket tightly using heavy-duty anchor bolts.

• Verify level with spirit level.

2.3 Hanging the Unit

• Lift heater (minimum 2 persons for 30–50 L units).

• Hook securely onto the bracket.

• Ensure heater is firmly seated and level.

• Shake lightly to confirm stability (no movement).

3️⃣ Plumbing Connection

3.1 Cold Water Inlet Connection

• Identify blue marked inlet port.

• Install:

  • Stop valve (for maintenance shut-off).

  • Non-return valve (NRV) – prevents hot water backflow.

  • Pressure relief valve (PRV) – mandatory for safety (usually pre-installed).

• Use PTFE tape on all threaded connections.

• Connect the cold water supply pipe securely.

3.2 Hot Water Outlet Connection

• Identify red marked outlet port.

• Connect hot water pipe leading to shower or mixer tap.

• Use SS braided hose (high-temperature rated) or copper piping.

• Check flow direction and ensure no sharp bends.

3.3 Pressure Relief Drain Pipe

• Connect a ½" drain pipe from PRV outlet to nearest floor trap.

• Ensure pipe slope allows full drainage.

• Do not cap or block PRV drain outlet.

3.4 Pipe Support & Insulation

• Secure all pipes with clamps or saddles at 600 mm spacing.

• Wrap thermal insulation foam on hot water pipe to reduce heat loss.

4️⃣ Electrical Connection

⚠️ To be done by a Licensed Electrical Worker (LEW) in Singapore.

4.1 Circuit Preparation

• Ensure a dedicated power circuit from DB box:

  • 15 A to 20 A MCB, 2.5–4 mm² cable size (depending on heater rating).

• Install 20 A double-pole isolator switch with indicator lamp outside the bathroom (splash-proof type).

4.2 Wiring the Heater

• Connect Live (Brown/Red), Neutral (Blue/Black), Earth (Green/Yellow) wires correctly.

• Tighten terminal screws firmly.

• Use heat-resistant cable and conduit.

• Properly connect earth wire to the heater’s earthing terminal.

4.3 Electrical Safety Check

• Test circuit with multimeter for continuity and voltage.

• Ensure isolator works properly.

• Confirm there is no power before opening or closing connections.

5️⃣ Testing & Commissioning

5.1 Water Filling

• Open cold water inlet valve slowly to fill the heater tank.

• Keep a hot tap open to allow air to escape until water flows steadily.

• Check all joints for leaks; retighten if necessary.

5.2 Power On

• Once the tank is full, switch on power.

• Observe the indicator light—it should turn on.

• Allow heating for 10–15 minutes (depending on tank capacity).

5.3 Functional Tests

• Verify:

  • Water temperature at outlets.

  • No unusual noise or vibration.

  • No leakage from PRV or joints.

  • PRV operates correctly when manually released.

6️⃣ Final Inspection & Handover

• Check all fasteners and supports again for tightness.

• Clean installation area.

• Label isolator switch clearly: “WATER HEATER”.

• Provide user the following:

  • Heater manual & warranty card.

  • Demonstrate ON/OFF operation.

  • Safety precautions (turn off when not in use).

  • Maintenance advice (service every 2–3 years).

7️⃣ Safety Notes

• Never operate heater without water inside (will damage heating element).

• Ensure PRV is not blocked or plugged.

• Always switch off power before maintenance.

• Use only original manufacturer parts for replacement.