What you will know after this guide
- Choose the type
- Parts and functions
- Replacement sequence
- What the homeowner can do
Choose the type
Compare electric storage, gas, heat-pump, tankless and indirect units. Check draw profile, peak hour, bathrooms, incoming-water temperature, space, drain, noise, ventilation, power supply and local energy cost.
Parts and functions
- Shutoff valves: isolate the appliance.
- Dielectric fittings where required: limit corrosion between incompatible metals.
- Temperature-pressure relief valve and discharge tube: relieve dangerous pressure.
- Pan and drain: contain leakage where location requires it.
- Expansion tank: absorb thermal expansion in a closed system.
- Thermostatic mixing valve: limit delivered temperature where designed and required.
- Disconnect, cable, breaker or gas/vent connection: provide a compliant energy supply.
Replacement sequence
Confirm permits and required trades; identify and lock out energy sources; close water; cool and drain safely; remove without damaging the building; verify base, clearances, drainage and capacity; install to the manufacturer; fill and purge fully before energizing; verify leaks, relief valve, temperature, venting and operation.
What the homeowner can do
Measure the space, record model and input, document connections, compare quotes, clear access, protect floors, monitor leaks and retain records. Do not alter gas, combustion, fixed wiring, relief protection or structure without legal authority and competence.
Commissioning and closeout
Require model number, warranty, permit/inspection, photos of hidden connections, settings, measured temperature, leak test, venting verification and maintenance date. Add a water detector and place the shutoff on the emergency sheet.
