Is the A.O. Smith SUN-120 110 suitable for your solar water-heater system?
The A.O. Smith ProLine SUN-120 110 is a 120-gallon direct solar booster tank for a residential solar-thermal hot-water system. The tank stores water heated by solar collectors and includes a single 4,500-watt electric backup heating element for periods when solar energy is not sufficient. It is not a complete solar system: solar collectors, circulating pumps, controls, heat exchangers and related components are not included.
The SUN-120 110 is A.O. Smith’s larger direct-solar storage/booster tank, marketed in the 120-gallon class but listed at 119 gallons nominal capacity on the exact-model product page. This distinction matters when comparing tank capacity and floor space. Water Heating Experts serves Palm Beach Gardens, Jupiter and neighboring communities and can review the existing storage tank, piping and replacement requirements. A complete collector-system installation or repair may require coordination with a qualified solar-thermal specialist; WHE confirms the project’s scope before accepting the work.
Direct/open-loop and closed-loop solar connections
A.O. Smith designs this tank for a direct (open-loop) potable-water solar circuit or a closed-loop collector circuit using a separate external heat exchanger. In an open-loop arrangement, potable water circulates through the compatible collector circuit. In a closed-loop arrangement, the collector fluid must remain separate from potable water through an appropriate heat exchanger; the collector fluid does not belong in the household drinking-water tank.
The manufacturer’s dimensional drawing shows ¾-inch domestic hot and cold connections, 1-inch top connections for the collector supply and return, and optional plugged 1½-inch NPT side connections. Proper design depends on the existing collectors, solar-loop piping, circulation pump, control strategy, backflow protection and freeze/overheat protection. A dedicated solar sensor mounting point is provided, but the surface-mount temperature sensor is supplied separately.
Tank dimensions and replacement considerations
The manufacturer’s AOSRE50500 dimensional table lists 63¼ inches high and 28 inches in diameter, with approximately 311 pounds shipping weight. The product page separately lists 66⅜ inches shipping height and 312 pounds shipping weight. These are shipping measurements, not extra claims about installed height; check the exact delivered unit, doorways and service access. We also confirm the full overhead clearance for collector and domestic connections, electrical and thermostat access, service of the anode rod, drain pan, temperature-and-pressure relief discharge and a safe removal path.
The SUN-80 110 has a narrower 24-inch tank, compared with 28 inches for this 119-gallon model. Both share the same 4,500-watt electric backup and published 21-gallon-per-hour recovery at a 90°F rise. The larger tank provides storage, not faster electric-only reheating. Compare the A.O. Smith SUN-80 110 when choosing an appropriate size. Solar collectors and any existing heat exchanger should be evaluated for the selected storage volume; a larger tank alone does not increase the solar energy available.
240V electric backup and hot-water safety
The electric backup is listed at 240 volts and 4,500 watts maximum input, with approximately 21 gallons per hour recovery at a 90°F temperature rise when operating on the element. The actual delivered unit and the existing circuit, breaker, wiring and controls require verification before installation. This recovery specification describes the electric element, not the variable heat supplied by solar collectors.
Solar collectors may raise stored water to temperatures above normal domestic-use levels, so scald protection and an appropriate thermostatic mixing/tempering valve are important parts of the full system design. WHE also reviews thermal expansion control, relief-valve discharge and water pressure. We do not assume an existing solar controller, sensor or mixing valve is safe or compatible simply because the storage tank has the right gallon capacity.
Tank protection, care and warranty
A.O. Smith lists its Blue Diamond glass lining, CoreGard anode, DynaClean sediment-reduction features, brass drain valve, dry-fire protection and heat-trap nipples. The unit has a six-year limited tank and parts warranty subject to the written terms. Periodic inspection of the anode, relief valve, solar loop and backup controls remains important. Manufacturer warranty coverage is not an automatic labor guarantee.
No rebates, tax credits or energy savings are guaranteed. The manufacturer specification sheet is a historical March 2013 document and includes an old federal tax-credit statement; that historical statement should not be treated as current eligibility. WHE confirms equipment suitability and job scope separately.
SUN-120 110 frequently asked questions
Does this model include roof solar collectors?
No. The SUN-120 110 is a storage/booster water heater with a 4,500-watt electric backup element. Solar panels/collectors, circulation equipment and solar controls are separate items that must be designed or matched to the existing system.
Can it be connected to an open-loop or closed-loop solar system?
Yes. The manufacturer describes direct/open-loop potable-water circulation and closed-loop solar collectors through a separate, compatible external heat exchanger. WHE confirms whether the existing plumbing and solar controls are appropriate before recommending replacement.
What is the electric backup recovery rate?
At 240 volts, A.O. Smith lists one 4,500-watt backup element and about 21 gallons per hour recovery at a 90°F rise. Solar contribution varies with sunlight, collector sizing and controls and is not included in this electric-only figure.
How does this compare with the SUN-80 110?
The SUN-80 110 has a narrower 24-inch tank, compared with 28 inches for this 119-gallon model. Both share the same 4,500-watt electric backup and published 21-gallon-per-hour recovery at a 90°F rise. The larger tank provides storage, not faster electric-only reheating. The correct choice depends on hot-water demand, solar equipment and available installation space.
Can WHE replace this solar water-heater tank in Palm Beach Gardens or Jupiter?
Water Heating Experts can review residential storage-tank replacement needs in Palm Beach Gardens, Jupiter and nearby areas. Text photos of the existing tank label, collector-loop piping, controls and access. We will confirm whether the solar work is within our scope or needs coordination with a solar-thermal specialist before providing an estimate.
Discuss a solar hot-water storage replacement with WHE
Text a clear photo of the existing tank’s model and electrical label plus wider photos showing the collector supply/return, controls, circulating pump and water connections. That helps WHE assess whether this A.O. Smith water-heater option fits the actual solar-thermal installation. Final equipment availability, pricing and scheduling are confirmed with your estimate.
Manufacturer sources: A.O. Smith SUN-120 110 product page; Direct Solar Booster specification sheet AOSRE50500 (March 2013); manufacturer installation and care manual 100228290; and limited warranty 321541. Historical specification-sheet tax-credit claims are not current incentive guidance. Verify current codes, exact unit specifications, system compatibility and local program rules.