Safe checks before a generator repair call
Some no-start calls turn out to be a switch left in the wrong position. These checks are safe for an owner:
- Controller mode: it should show Auto. Units sometimes get left in Off after service or a power blip.
- Display: write down the exact alarm or error message. It's the most useful thing you can tell a technician.
- Fuel: the gas valve at the unit is open, or the propane tank has fuel in it.
- Breaker: the generator's own main breaker is on. Set the controller to Off before you lift the lid to look.
Stop there. Don't reach into the engine compartment while the unit is in Auto, because it can start on its own. Don't open the transfer switch, which holds live utility power. If you smell gas, leave the area and call your gas utility from a safe distance.
Generac generator won't start or the battery is dead
If the engine doesn't crank at all, the battery is the usual suspect. Cold weakens batteries, and the built-in charger can only keep a healthy battery topped up. An old battery often dies on the first frigid exercise run of the winter, and you find out when the power goes out. A technician load-tests it and replaces it if needed.
If it cranks but won't fire, look at fuel and spark: a closed valve, an empty propane tank, low gas pressure, or fouled spark plugs. The controller usually logs an overcrank alarm after a few failed attempts.
Generator error codes and what they point to
Generac controllers name the alarm on the display. A few you'll see often:
- Overcrank: it tried to start and couldn't. Think fuel, spark or battery.
- Low oil pressure: low oil level or a sensor problem. Don't keep restarting it.
- Underspeed or RPM sense loss: the engine isn't holding speed, often fuel supply or an overload.
- Low battery: a weak battery or a charger issue.
Clearing the code by cycling Off and Auto may get it running today. It doesn't fix the cause. Put the exact wording in your repair request.
Transfer switch faults and rough running generators
Sometimes the generator runs fine but the house stays dark, or the house stays on generator after the grid comes back. Both point to the transfer switch or its controls, not the engine. That's a technician job because of the live utility power inside.
Rough running shows up as surging lights, stalling when the furnace or central air kicks on, or the unit shutting down under load. Causes include fouled plugs, a clogged air filter, low gas pressure when the gas meter or line is too small for the furnace and generator running together, a propane regulator icing up, or simply more load than the generator was sized for. A well pump and central air starting at the same moment can push a smaller unit over its limit.
Generator repair after an ice storm or long outage
A unit that carried your house through a multi-day outage is probably due for an oil change, and a good technician will check it over at the same visit. After a storm, also look for snow or ice packed against the vents, branches on the enclosure, and signs of mice nesting inside, which happens a lot in fall.
If it didn't run at all during the outage, call now, not in the middle of the next one. A problem found on a clear afternoon is easier to fix than one found in the dark. Regular generator maintenance catches most of these before they strand you.
If the repair estimate starts to rival a new unit, compare it with a quote for a standby generator installation. We match homeowners with repair technicians across the region, from Troy to Clifton Park.