A standby generator might run for an hour a month on test, then sit there. The one time it really matters is the night the mains fails. A service agreement is how you make sure it starts, takes the load and keeps going. Here’s what a good one covers, and what to check before you sign.

1. Planned visits matched to your run hours

Most standby sets need a major service once a year, plus a minor visit every six months or every 250 to 300 run hours, whichever comes first. Prime power sets, hybrid sites and critical sites like hospitals need more. A good agreement sets the visit count from how your set is actually used, not a one-size schedule.

A major service should include oil and filters (oil, fuel and air), coolant checks and top up, belts and hoses, a battery and charger test, and a full run on load.

A minor service is an inspection and run test: fluid levels, leaks, battery condition, alarms and a check of the control panel’s event log.

2. The control system, not just the engine

This is where many agreements fall short. The engine can be perfect, but if the controller has a fault, a wrong setting or a flat backup battery, the generator won’t start when the mains fails. Every PCAS visit includes a controller health check: alarms, setpoints, event log and firmware. As a ComAp Authorised Solutions Provider, we can also fix and upgrade the controller, which most service companies can’t.

3. A real changeover test

The generator starting isn’t the whole test. The automatic mains failure (AMF) panel or transfer switch has to see the mains drop, start the set and move the load across. Where the site allows, we test the full changeover under load, then switch back.

4. Load bank testing

A standby set that only ever runs off load slowly fouls up (wet stacking) and never proves it can carry full power. A yearly load bank test runs it at full load for a set time and records the results. It’s the only way to know the set will do its job.

5. Fuel checks

Diesel stored for months picks up water and can grow diesel bug, which blocks filters at the worst moment. A fuel sample once a year, or every visit on critical sites, catches it early. Fuel polishing and tank cleaning fix it.

6. A 24/7 callout that’s actually answered

Check who picks up the phone at 2am, and how fast an engineer gets to you. PCAS agreements all include a 24/7 emergency line, with faster response on our higher plans.

7. A written report every visit

You should get a report after every visit with readings, photos and anything that needs attention. It’s your evidence for insurers and auditors.

Choosing a plan

PCAS offers three plans: Essential for small, low-hours standby sets, Standard for most commercial and agricultural sites, and Critical for hospitals, data centres and hybrid sites. All three include the 24/7 callout line. You can add your ACBs and switchgear to the same agreement.

See our service agreements

PCAS already services standby generators for Sheffield hospitals, data centres on the south coast, a football stadium in Yorkshire, and a national cold storage operator.

PCAS provides 24/7 generator service agreements across Yorkshire, the North West and the UK. Call 0114 317 7939 or email support@pcasltd.com.

Have a question about this article? Email support@pcasltd.com or call 0114 317 7939.