Is the A.O. Smith GCR-30R 400 right for your gas water heater replacement?
The A.O. Smith ProLine GCR-30R 400 is a 30-gallon nominal tall natural-gas storage water heater with atmospheric venting. At Water Heating Experts, we assess the household’s hot-water use, existing natural-gas supply, combustion air, vent route and available installation space before recommending a replacement in Palm Beach Gardens, Jupiter or nearby Palm Beach County communities.
A.O. Smith lists 29 gallons rated storage, a 62-gallon first-hour rating, 32,000 BTU/h natural-gas input, and 0.60 Uniform Energy Factor (UEF) for this exact model. First-hour rating is a standardized delivery figure, not the volume inside the tank or a guarantee of uninterrupted showers. Its published recovery is approximately 31 gallons per hour at a 90°F temperature rise.
Size, installation access and choosing a capacity
The manufacturer lists 56.5 inches tall × 18 inches in diameter. These tank dimensions do not include every vent, draft-hood, piping or service clearance. Its 18-inch cabinet diameter is the narrowest of the three selected GCR natural-gas models. It can be worth considering where the household’s usage is modest and a taller, narrower heater is practical. We also review the path for removing the old heater, shutoff valves, drain pan or drainage provisions and the temperature-and-pressure relief discharge.
Compare the A.O. Smith GCR-40 410 (40 gallons) and A.O. Smith GCR-50 400 (50 gallons) if another size better matches the household. The manufacturer’s short promotional bullet states 52 gallons first-hour delivery and 0.55 UEF, but its exact-model technical table and AOSRG47000 sheet give 62 gallons and 0.60 UEF. This guide uses the technical figures, not the conflicting bullet.
Atmospheric venting and natural-gas requirements
Unlike a power-vent or sealed direct-vent model, the GCR-30R 400 uses atmospheric draft-hood venting and must have an appropriate vent system that operates safely. The model uses 3-inch listed flue outlet; confirm listed draft hood and complete vent system. WHE checks combustion and dilution air, flue sizing and slope, connector condition, shared-venting conditions, the gas supply and the applicable local installation requirements. A water heater cannot safely be selected on gallon size alone when an existing vent system is unsuitable.
This is a natural-gas model; the propane model is separately identified by the manufacturer. We do not assume it can be used with propane or converted without manufacturer-approved equipment and procedures. The gas control includes a pilot with piezo ignition, electronic temperature regulation and a status indicator. Venting and combustion performance must be verified during installation.
Tank features, maintenance and warranty
A.O. Smith lists the Green Choice low-NOx burner design, a Blue Diamond glass-lined tank, stainless-core CoreGard anode rod, DynaClean sediment-reduction dip tube, factory-installed heat-trap nipples and brass drain valve. These features do not remove the need for maintenance, attention to water quality or safe combustion-air pathways. The model carries a six-year limited tank and parts warranty, subject to the written warranty. Manufacturer parts coverage does not automatically include removal or installation labor.
GCR-30R 400 frequently asked questions
Is this the natural-gas or propane model?
The GCR-30R 400 is the natural-gas configuration with 32,000 BTU/h input. Propane models use different exact suffixes and have their own manufacturer specifications. WHE verifies the fuel supply and delivered unit before installation.
What does the 30-gallon rating mean?
The nominal model capacity is 30 gallons, and A.O. Smith lists 29 gallons of actual rated storage. Its 62-gallon first-hour rating measures standardized hot-water delivery, not physical tank storage.
Can this replace a power-vent or direct-vent water heater?
Not as an assumed like-for-like replacement. The GCR-30R 400 uses atmospheric venting. WHE must inspect the existing vent design, combustion air and installation requirements before selecting equipment; a power-vent or direct-vent setup may call for a different model.
Will it fit in the space used by the old gas water heater?
The listed tank body measures 56.5 inches high by 18 inches in diameter, but vent hood, draft connector, top piping and service access require extra room. We confirm clearances and vent compatibility from the installation and manufacturer’s instructions.
Does an estimate reserve this exact model?
No. A free WHE estimate is an opportunity to review your location, household demand, venting, gas supply and installation conditions. Availability, price and scheduling are confirmed separately.
Discuss a gas water heater replacement with WHE
Text a clear picture of the existing water heater’s data label along with a wider photo showing its gas connection, draft hood and vent route. We can compare A.O. Smith ProLine models and discuss the work needed. For general guidance, see our gas water heater installation guide and A.O. Smith installation options.
Technical sources: A.O. Smith GCR-30R 400 exact-model product page; A.O. Smith AOSRG47000 atmospheric-vent ProLine specification sheet (family reference; series revisions differ); manufacturer standard atmospheric-vent installation manual 100263112; and residential limited warranty. Current technical values govern over conflicting marketing copy. Confirm delivered-unit labeling, current specifications, venting, fuel and installation requirements before work begins.