Kenmore water heater installation follows standard residential glass-lined tank install procedure. Underneath, Kenmore is A.O. Smith or State Industries — both standard US-built designs with no installation surprises.
Pre-install checklist
- Verify proper electrical circuit (30A 240V for electric) or gas line + venting (gas)
- Confirm cold-supply shutoff valve in working order
- Plan expansion tank installation if not already present (required by most US municipal code)
- Verify drain pan availability if installed above finished space
- Have new T&P valve and discharge tube ready
- Confirm correct tank rough-in measurements match install location
Tools you'll need
- Pipe wrench (12" or 14")
- Channel-lock pliers
- Adjustable wrench
- Multimeter (electric model verification)
- Tubing cutter (if cutting/extending water lines)
- Garden hose (for draining old tank)
- Towels and bucket for drips
- Two-person lift or appliance dolly
Step 1: Drain and remove the old tank
- Shut off power (electric) or gas (gas)
- Shut off cold-water supply
- Open hot faucet upstairs to break vacuum
- Connect garden hose to drain valve, route outside or to floor drain
- Open drain valve — full drain takes 20–40 minutes
- Disconnect electrical (electric) or gas line (gas)
- Disconnect cold inlet and hot outlet with pipe wrench
- Tip and walk the old tank out — use appliance dolly
Step 2: Position the new Kenmore tank
Place in drain pan, level (within 1/4 bubble). Allow 1.5" of clearance around the tank for service access.
Step 3: Connect cold inlet
From cold supply working toward the tank:
- Full-port ball valve (shutoff)
- Tee for expansion tank
- Dielectric union (Kenmore ships these — use them)
- Cold inlet of tank
Wrap fittings with Teflon tape (3–4 wraps clockwise). Hand-tighten plus 1/4 turn with wrench.
Step 4: Connect hot outlet
Dielectric union into hot main. Avoid hard 90° elbows immediately at the tank top.
Step 5: T&P valve and discharge tube
Kenmore ships with T&P pre-installed. Verify torque, route discharge tube downward to within 6" of floor or drain. Do not reduce diameter or cap.
Step 6: Electrical (electric models)
- Verify breaker is off and locked out
- Open junction box on top of tank
- Connect L1 to L1 (black), L2 to L2 (red), ground to ground
- Torque terminals to 18–22 in-lb
- Close junction box
Step 7: Gas connection (gas models)
- Verify shutoff valve at gas supply, downstream of meter
- Connect new flex line from supply to gas valve
- Pressure-test the connection (soap solution; bubbles = leak)
- Connect vent pipe (verify rise, slope, and termination per local code)
- Verify damper functioning correctly (for power-vent models)
Step 8: Fill tank — CRITICAL
- Close drain valve
- Open cold supply slowly
- Open hot faucet upstairs to release trapped air
- Wait for steady stream from hot faucet (5–10 minutes for 50-gal fill)
- Verify no leaks at any connection
Never restore power or light gas burner with an unfilled tank. Dry-firing destroys electric elements; cooking gas residue on dry tank wall damages glass lining.
Step 9: First heat
Restore power (electric) or light pilot per instructions and turn to setpoint (gas). Verify tank reaches setpoint within 60–90 minutes (electric 50-gal from cold) or 30–60 minutes (gas).
Step 10: Final verification
- Visual leak check around all connections
- Verify T&P valve operates (lift test once tank is hot)
- Verify thermostat cycles correctly (electric: both thermostats; gas: gas valve modulates)
- Register warranty within 60 days of installation
Common Kenmore install mistakes
- Missing expansion tank (causes T&P weeping later)
- Direct copper-to-tank connection without dielectric (galvanic corrosion in 3–5 years)
- Dry-firing elements before tank fill
- Loose electrical terminals (arcing failures)
- Forgetting to register the warranty within 60 days