The ELD66-D is Rheem’s 65-gallon Light Service model
The Rheem ELD66-D is an electric resistance storage water heater for commercial applications with moderate hot-water demand, such as small offices and retail spaces. Although the model number contains “66,” Rheem’s current specification table lists 65 gallons. It is the smallest tank in this three-size ELD-D range.
Its narrower 23-inch tank can help when equipment-room width is limited, but the electrical service remains a major selection point: this model requires the published 277-volt configuration. WHE reviews the fixtures served and the building’s supply before recommending it for a replacement.
Verified ELD66-D specifications
| Published tank capacity | 65 U.S. gallons (ELD66-D model designation) |
|---|---|
| Heater type / fuel | Light Service commercial storage tank / electric resistance |
| Electrical input | 12,100 watts total; two 6,050-watt elements |
| Power and wiring | 277 volts; single phase; simultaneous, two-wire operation |
| Published full-load current | 44 amperes |
| Recovery | 81 GPH at a 60°F rise; 61 GPH at an 80°F rise; 49 GPH at a 100°F rise |
| Height × diameter | 58¾ × 23 inches |
| Water connections | ¾-inch NPT top connections on 8-inch centers; ¾-inch T&P connection |
| Approximate shipping weight | 170 lb; filled installation weighs more |
| Maximum working pressure / water temperature | 150 psi / 181°F |
| UEF / first-hour rating | Not published for these ELD-D models in the linked product page and specification sheet |
| Standard published limited warranty | 6 years tank / 1 year parts; certificate conditions apply |
Recovery measures water reheated each hour at the stated temperature rise; it is not a first-hour rating or a guaranteed usable draw. Rheem does not give an exact UEF or first-hour rating for this model in these sources. We do not substitute the ratings of the separate ELD-TB or residential product ranges.
When the smaller tank makes sense
Compared with the ELD80-D, the ELD66-D is 1½ inches narrower and has 15 fewer gallons of published storage. Their heights are nearly the same. If shortages happen during a brief busy period, the extra storage of the 80 may help; if demand stays above the heater’s recovery for an extended period, increasing storage alone will not solve the underlying sizing problem.
ELD66-D, ELD80-D and ELD120-D compared
| Model | Published capacity | Height × diameter | Approx. shipping weight |
|---|---|---|---|
| ELD66-D | 65 gallons | 58¾ × 23 inches | 170 lb |
| ELD80-D | 80 gallons | 59 × 24½ inches | 200 lb |
| ELD120-D | 119.9 gallons | 62½ × 28¼ inches | 330 lb |
All three share the same published 12.1-kW input and recovery figures. Increasing tank size provides more stored water for a concentrated draw; it does not increase the rate at which these elements replace that heat. We compare the busiest period of use, incoming water temperature and the time available between draws before selecting a size.
Electrical supply and installation planning
Verify 277-volt service before ordering. Rheem lists two 6,050-watt elements operating simultaneously on a single-phase, two-wire supply, with 44 amperes full-load current. That is an equipment load, not a specified breaker size. The installer must match the unit nameplate and wiring diagram, then determine the branch circuit, overcurrent protection, disconnect and grounding for the actual installation. The linked general manual covers multiple configurations; its tables must not be used to assume this model is a 240-volt or three-phase unit.
This resistance heater has no combustion exhaust, gas connection or heat-pump condensate drain. It still needs a suitable indoor location, safe relief-valve discharge, leak management and room to service the elements, thermostats and anode. WHE checks thermal expansion provisions where the plumbing system is closed. The floor must support the filled tank; shipping weight alone is not the installed load.
Rheem lists a maximum water temperature of 181°F. That is a capability limit, not a recommended temperature at a handwashing sink or shower. Storage temperature and point-of-use mixing need to suit the application and protect users from scalding. A large commercial tank should not be selected for a home solely because the gallon count matches the old heater.
Warranty and documentation notes
Rheem’s linked commercial warranty certificate AP23781 specifies a six-year limited tank warranty and one-year limited parts warranty for the original owner, subject to its conditions and exclusions. It does not cover labor for service, repairs or reinstallation, permits, or removal and disposal. Coverage must be checked against the supplied unit and installation records.
There is a conflict within the manufacturer documentation: the March 2025 specification sheet promotes six-year tank coverage on its first page, but its trade-specification boilerplate on page two says three years. The product page, feature sheet and attached warranty certificate support the six-year tank / one-year parts terms above. Confirm the applicable certificate with the supplied heater rather than treating the boilerplate as a separate warranty offer.
Have WHE review the proposed installation
For an installation review in Palm Beach Gardens, Jupiter or nearby Palm Beach County communities, send the current heater’s rating plate, a wide photo of the setup and a description of peak hot-water use. We check the equipment fit and work required before providing an estimate. See our electric water heater installation guide and Rheem installation page for related options.
Frequently asked questions
Is the ELD66-D a 66-gallon or 65-gallon heater?
ELD66-D is the model designation, but Rheem lists 65 U.S. gallons in the current product page and specification table. WHE uses that published capacity for this guide.
Can this heater connect to a standard 240-volt water-heater circuit?
The ELD-D specification here is 277 volts, single phase, with simultaneous elements. Do not assume compatibility with an existing 240-volt circuit or an alternate configuration. Have the supplied unit and building electrical service verified before purchase.
Does a larger ELD-D tank heat water faster?
No. These three models share 12.1-kW input and the same published recovery: 49 gallons per hour at a 100°F temperature rise. A larger tank provides more stored hot water.
Does it need a vent or a heat-pump drain?
It has no combustion vent and no heat-pump condensate drain. It still needs proper relief discharge, leak protection, electrical connections and service access.
What warranty does Rheem publish for the ELD-D?
The attached certificate lists six-year limited tank coverage and one-year limited parts coverage, subject to its terms. Labor and installation-related costs are excluded. A conflicting three-year boilerplate statement in the specification sheet is noted above; verify the certificate supplied with the unit.
Manufacturer references
Verified against Rheem’s ELD66-D product page, Light Service specification sheet RR102CE-12 Rev. 3 (March 2025), commercial electric Use & Care Manual AP17463, warranty certificate AP23781 and ELD-D feature sheet. The unit’s current nameplate and installation instructions govern the final installation.