Find a commercial generator service

A facility manager's vetting checklist: load studies, the testing a real service actually does, maintenance contract red flags, and the questions that separate genset pros from truck-and-ladder outfits.

First: know your own numbers

Before you call anyone, walk in with two figures from your own building. One: the actual running load, not the generator's nameplate. A diesel that loafs far below its rating is a wet-stacking engine waiting to foul. Two: the largest single motor start — chiller, fire pump, elevator — because surge, not steady state, sizes the installation. The generator size calculator gets a facility list into rough shape; a contractor should then perform a load study with a logger before quoting anything. A contractor who quotes off a nameplate walk-through without a load study is selling you a unit, not a system.

Related planning pages: mixing a diesel nameplate into the gasoline fuel rule is on diesel standby generator. Kubota's own GL7000-USA sheet is on Kubota standby generator. Cord-versus-transfer-switch work is on backup generator installation. Generac's 20 kW Guardian column is on 20 kW home standby generators. A cord-and-plug tool list, and the point where that math stops, is on how to size an industrial generator.

The testing schedule a real service follows

Emergency and standby systems are governed by the standard your insurer, fire marshal, or accreditation body cites. Hospitals may also answer to the Joint Commission. This page does not reprint test intervals from a standard it has not opened. Every visit should land in a written log you can hand an inspector.

Contract red flags

• Load-bank testing billed as a surprise add-on — it's the annual core of diesel PM, not an upsell.
• No response-time commitment in writing. A vague emergency-service promise means nothing without a contractual response time.
• They don't touch transfer switches. The ATS is the single most-failed component in standby systems; a service that only turns wrenches on the genset leaves you exposed.
• No compliance documentation. If their visit reports wouldn't satisfy your fire marshal or insurer, you're paying for logs you can't use.
• Fuel maintenance never mentioned. Stored diesel degrades. Polishing and biocide are recurring line items, not emergencies.

The vetting questions

1. Are your technicians EGSA-certified or factory-trained on our unit's brand?
2. Will you perform a load study before recommending any change?
3. Is load-bank testing included in the annual contract price?
4. What's the contractual emergency response time?
5. Do you service automatic transfer switches and ATS controls in-house?
6. Do you provide AHJ/insurer-ready compliance documentation?
7. Can you support a maintenance account across multiple facilities, or is this a one-truck operation?

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FAQ

What does commercial generator service cost?

This page does not print a contract price. Cost scales with kilowatt class, fuel type, and whether load-bank testing is included. Get quotes and compare line items, not totals. The cheap contract often excludes load-bank and transfer-switch work.

Install or replace: what does the project involve?

Site survey and load study, permitting, a poured pad, fuel supply (sub-base tank or utility gas), wiring through a transfer switch, and commissioning with a witnessed acceptance test. Budget weeks-to-months for permitting and inspection depending on jurisdiction — the equipment is the fast part.

Can we service in-house instead?

Small facilities with a trained maintenance tech can handle weekly/monthly checks, but most commercial operators outsource: the annual load-bank test, ATS service, and fuel polishing need equipment and certifications most shops don't carry, and the compliance log is the real deliverable.