Generator Services in Greenwich, CT: Repair, Installation and Maintenance

The Most Reliable Generator Service and Sales Since 1981

National Standby Repair serves homeowners, commercial facilities, medical properties, and other customers throughout Greenwich and western Connecticut. Since 1981, our technicians have worked on standby power systems from Generac, Kohler, Cummins, Onan, Briggs & Stratton, WINCO, and many other manufacturers. We handle new installations, repairs, scheduled maintenance, commercial testing, rentals, and 24/7 emergency service for customers who need dependable support before, during, or after an outage.

Generator Installation

Whole-House Generators

We review the property before recommending a residential system. Electrical demand, fuel availability, equipment placement, service access, and the systems you want available during an outage all affect sizing. Some homes need broad coverage for heating, cooling, refrigeration, pumps, security equipment, or medical devices. National Standby Repair sells and installs residential generators from several major manufacturers and can recommend equipment based on the home and the load you want to support.

Commercial Generators

Commercial installations often involve larger electrical loads, automatic transfer equipment, and more involved site planning. We install generators for medical facilities, offices, apartment buildings, schools, restaurants, municipal properties, and other commercial sites in Greenwich. Our team reviews the building’s demand, fuel source, equipment location, and operating requirements before recommending a system. We can also coordinate with qualified electricians, plumbers, or gas contractors when their work is part of the project.

Generator Brands

National Standby Repair sells and services Generac, Kohler, Cummins, Onan, Briggs & Stratton, WINCO, and other established brands. The right choice depends on more than the manufacturer name. Fuel type, expected load, system controls, available space, and long-term service access all affect which model makes sense for the property.

Generator Repair

Startup and Shutdown Problems

A missed exercise cycle, no-start condition, fault code, or unexpected shutdown can point to several different issues. Our technicians diagnose problems involving batteries, starters, sensors, fuel delivery, alternators, and control boards. We work on newer and older equipment, including systems installed by other companies. In many cases, a thorough diagnosis can show whether the unit is worth repairing before replacement is considered.

Transfer Switch and Control Repairs

The generator can run properly and still fail to power the building if the transfer equipment is not working as it should. Our technicians diagnose automatic transfer switch faults, control problems, sensor issues, and communication failures between the generator and the electrical system. We can also test transfer operation during maintenance or troubleshooting when the symptoms point to a control-side problem.

Emergency Repairs

National Standby Repair provides 24/7 emergency generator service throughout our service area. We respond when a system will not start, loses output, overheats, develops a fuel problem, or fails to transfer power during an outage. Our technicians work on systems used by homes, medical facilities, apartment buildings, offices, and other commercial properties.

Generator Maintenance

Scheduled Service

Routine service helps us find wear and operating problems before the generator is needed for an extended run. A maintenance visit may include oil and filter changes, battery testing, fluid checks, wiring inspection, exercise-cycle review, and examination of the controls and transfer equipment. The exact work depends on the generator, its age, and how much it has been used.

Annual Service Contracts

National Standby Repair offers annual service contracts for customers who want regular maintenance and priority support. Contract service can include routine service, testing of transfer switches and programming, and work from factory-trained technicians. Fixed annual rates also give property owners and facility managers a more predictable way to plan for recurring generator service.

Warranty Repairs

Our technicians provide qualified warranty repair service for Kohler, Cummins, Generac, GE, Briggs & Stratton, and WINCO equipment. We handle the repair work and coordinate the warranty process where applicable. We also service many other manufacturers outside of warranty.

Commercial Testing

Load Bank Testing

Load bank testing places the generator under controlled electrical demand so our technicians can evaluate how it performs under load. We can review voltage, frequency, cooling performance, engine response, oil pressure, fuel pressure, and control behavior during the test. This can uncover weak output or operating problems that may not appear during a normal exercise cycle.

Fuel Testing

Stored diesel can collect water, sediment, sludge, bacteria, and other contamination over time. Those conditions may affect filters, injectors, or engine performance when the generator has to run for a prolonged period. National Standby Repair provides on-site fuel testing to assess the condition of the stored supply before treatment is recommended.

Fuel Polishing

If testing shows that the fuel can be recovered, filtration, scrubbing, or polishing may be more practical than replacing the full supply. These services remove contaminants from stored diesel and can help restore fuel quality. This can be especially useful for commercial facilities with larger tanks.

Commercial Rentals

20 kW to 500 kW Units

National Standby Repair rents commercial generators from 20 kW to 500 kW for outages, construction work, planned shutdowns, utility delays, equipment replacement, and temporary facilities. Available equipment includes units from Cummins, CAT, and WhisperWatt. We work with contractors, facility managers, municipalities, medical providers, and other organizations that need temporary power for short-term or extended use.

Rental Setup and Service

The right rental size depends on the load the temporary system needs to carry. Our team can review demand, recommend an appropriate unit, and assist with delivery, placement, setup, and installation. If the generator will remain on site for a longer assignment, we can also provide maintenance and service during the rental period.

Residential Generator Service

Existing Home Generators

Homeowners can call National Standby Repair for routine maintenance, battery replacement, transfer switch service, fault diagnosis, and repairs on existing systems. We also work on generators installed by other contractors. If an older unit is still in serviceable condition, our technicians can recommend repairs based on what we find instead of treating replacement as the automatic next step.

Larger Residential Properties

Homes with multiple HVAC systems, pumps, larger electrical services, security equipment, or other substantial loads may require more careful generator sizing and service planning. Our team reviews how the property uses power and which systems need to stay available during an outage. That information helps us recommend the right capacity and service approach for the equipment already in place.

Commercial Backup Power

Medical and Multifamily Properties

Medical offices, assisted living facilities, apartment buildings, and other multifamily properties may rely on backup power for pumps, elevators, HVAC equipment, refrigeration, security systems, or communications equipment. Our technicians can help with installation, repairs, maintenance, testing, and emergency service for these systems.

Offices and Other Businesses

National Standby Repair also works with offices, restaurants, dealerships, schools, warehouses, veterinary facilities, event venues, and other commercial properties. We service a wide range of generator sizes and fuel types, from smaller standby systems to larger units that support several building functions at once.

Serving Greenwich and Nearby Communities

National Standby Repair serves customers throughout Greenwich and nearby areas such as Stamford, Darien, New Canaan, Rye, Port Chester, and other communities in western Connecticut and southern Westchester County. From our location in Cold Spring, our technicians also travel throughout the Hudson Valley and North Jersey.

Frequently Asked Questions

Do You Service Generators Installed by Other Companies?

Yes. National Standby Repair services generators installed by other contractors, including older residential and commercial systems. Our technicians can inspect the equipment, perform maintenance, diagnose faults, and recommend repairs based on the condition of the unit.

What Generator Brands Do You Repair in Greenwich?

We service Generac, Kohler, Cummins, Onan, Briggs & Stratton, WINCO, ASCO, Avtron, Caterpillar, Kubota, Volvo Penta, and many other manufacturers. Our technicians work on generators across a broad range of sizes, ages, and fuel types.

How Do You Size a Whole-House Generator?

We review the electrical equipment you want to operate during an outage, along with starting loads, fuel availability, service equipment, and property layout. That information gives us a better basis for recommending capacity than a generic estimate.

What Does Generator Maintenance Include?

The exact work depends on the system, but maintenance may include oil and filter service, battery testing, fluid checks, wiring inspection, transfer switch review, exercise-cycle testing, and an inspection of the controls and enclosure.

When Is Load Bank Testing Recommended?

Load bank testing is useful when a generator spends long periods at low load, runs infrequently, or needs documented performance testing. It places the system under controlled demand and can reveal weak output, cooling problems, unstable voltage or frequency, and other issues.

Do You Provide 24/7 Generator Repair?

Yes. National Standby Repair provides 24/7 emergency generator service throughout our service area. We respond to startup failures, shutdowns, fuel problems, transfer switch faults, overheating, and other issues that prevent the system from operating properly.

Schedule Generator Service in Greenwich

Call National Standby Repair at (914) 734-1400 if your generator is not starting, needs maintenance, or is due for testing. We also help with new installations and temporary commercial power. Tell us what system you have and what you need help with, and our team can recommend the next step.