What a standby generator does when the power goes out: transfer, retransfer and the weekly exercise

When the utility fails, the generator’s controller waits out a start delay, cranks the engine and lets it warm up, and the automatic transfer switch (ATS) then moves the house to the generator. When the utility returns and holds, the switch moves the house back, and the engine runs a cool-down without load before it stops (Generac 10–26 kW manual, pp. 16, 20; Kohler TP-7092, pp. 30, 32). The numbers differ by brand: Generac’s 10–26 kW manual prints a 5-second start delay and a one-minute cool-down, Kohler a factory 3-second start delay with its Model RXT switch and a 5-minute cool-down, and the Briggs & Stratton 17–26 kW and Champion aXis manuals no start delay in seconds (Generac 10–26 kW manual, pp. 16, 20; Kohler TP-7193, p. 38; Kohler TP-7092, p. 32; Briggs 17–26 kW manual, p. 24; Champion aXis installation manual, p. 15). None of these documents adds the steps up to one time from outage to lights on.

The sequence, step by step

The switch takes the house off the utility before the generator powers it (Champion aXis installation manual, p. 48); in Generac’s words it “prevents electrical feedback between two different power sources” (Generac RXS switch manual, p. 9). A controller runs the timing. In Kohler’s system “All ATS control functions are performed by the RDC2 controller” (Kohler TP-7193, p. 12), and Briggs & Stratton’s 17–26 kW manual says “The generator’s controller monitors utility voltage.” (Briggs 17–26 kW manual, p. 24). Generac’s switch manual gives times in its load-shedding section and in its check of automatic operation: a five-second start delay, which it calls the “factory default setting”, a five-second warm-up delay, about 15 seconds before the switch returns the load to the utility and about one minute after retransfer before the generator shuts down, with the note “Timer durations may differ between generators and settings.” (Generac RXS switch manual, pp. 11, 21). The 10–26 kW and 10–28 kW generator manuals print the same start, warm-up, return and cool-down times, and the tables below follow the generator manuals. The controller has to be in AUTO: “The controller must be in AUTO mode for automatic transfer switch operation.” (Kohler TP-7092, p. 32).

1. The utility drops below the controller’s threshold (table below). Champion prints no threshold.
2. A start delay runs. Kohler: it “Guards against starting the generator set because of a brief change in the utility source.” (Kohler TP-7193, p. 38). On Generac’s 10–28 kW units the green Ready LED “flashes in two second intervals” while it runs (Generac 10–28 kW manual, p. 20).
3. The engine cranks in bursts with rests between them. After the last failed attempt the controller raises an alarm or fault (cranking table below).
4. The engine warms up before it takes the load. Kohler prints no warm-up: the switch transfers once the emergency source “reaches acceptable levels and stabilizes” (Kohler TP-7193, p. 11) and a 3-second delay has passed. Champion’s DIP switch 12 is a “Time delay for HSB to accept load”, which the manual does not call a warm-up (Champion ATS 102009 manual, p. 11).
5. The switch transfers the house to the generator. If the utility returns at any time from the start of the engine start sequence until the generator is ready to accept load, a Generac “completes start cycle and runs generator through its normal cool down cycle. However, load will remain on utility source.” (Generac 10–26 kW manual, p. 20).
6. The house runs on the generator. Large loads may wait several minutes (see “Big loads come back later”).
7. The utility returns and has to hold through a return delay. Kohler’s 2 minutes are there to make sure it is stable (Kohler TP-7193, p. 38).
8. The switch transfers the house back to the utility.
9. The engine cools down without load, then stops. That is why it keeps running after your lights are back on the utility: Kohler’s transfer switch “runs the generator set with no load to cool down the engine, and then stops the generator set” (Kohler TP-7092, p. 30), and the cooldown ends early “if the temperature drops below the cooled-down temperature level” (Kohler TP-7092, p. 32).
10. The controller waits in AUTO for the next outage or exercise.

Times as printed

Each row follows its own documents; “Not stated” means no number is printed. Generac’s Help Center speaks of “Guardian series generators with Evolution or Sync controllers” (Generac Help Center, “Can I Change the Exercise Cycle Duration?”, Jul 1, 2026), and calls the 10–28 kW models, G0072570 among them, the Next Generation series (Generac Help Center, “What are the model numbers for Next Generation series generators?”, Oct 23, 2025); the 10–28 kW manual itself does not print that name.

Model (document)	Utility lost below	Start delay	Before transfer	Utility back above	Return delay	Cool-down
Generac 10–26 kW, Evolution 2.0 (Generac 10–26 kW manual, pp. 16, 20, 34)	65% of nominal	5 s, “dealer programmable”; an IASD can set 2 to 1500 s	Warm-up 5 s; 30 s with Cold Smart Start, on at the factory, below 50 °F (10 °C) on 10–20 kW and 20 °F (-7 °C) on 22–26 kW	80% of nominal	15 consecutive s, dealer programmable	1 min
Generac 10–28 kW, Next Generation (Generac 10–28 kW manual, pp. 21, 23, 24)	65%	5 s, dealer programmable	Warm-up 5 s; 30 s with Cold Smart Start, off at the factory, below 50 °F (10 °C)	80%	15 consecutive s, dealer programmable	1 min
Generac PowerPact 7.5 kW (Generac PowerPact manual, pp. 15, 16)	65%	5 s	Warm-up 6 s, or 30 s with Cold Smart Start	80%	15 s	1 min
Kohler RCA(L) with Model RXT (Kohler TP-7193, pp. 33, 38; Kohler TP-7092, p. 32)	Dropout at 90% of pickup	3 s, factory-set	No warm-up printed; normal-to-emergency delay 3 s, factory-set	Pickup at 90% of nominal	2 min, factory-set	Set to 5 min, shorter once the engine has cooled
Briggs & Stratton 17–26 kW (Briggs 17–26 kW manual, p. 24; Briggs GC1030 manual, pp. 8, 9)	About 88%	“a timer”, no seconds; controller ranges: Mains Detect Delay 1–300 sec, Auto Start Delay 0–43200 sec	Not stated; controller range: Warm-Up Delay 0–60 sec	About 90%	Not stated; the manual names “a shut-down timer” that starts as the engine cools down, with no seconds; controller range: Return To Mains Delay 0–600 sec	5 min
Briggs & Stratton 200 A switch 209506, 2013 (Briggs ATS 209506 manual, p. 12)	70%	6 s	Warm-up 20 or 50 s, set with a jumper	80%	About 10 s, after at least 5 min of running	60 s
Champion 100515 and 100304, aXis, switch 102009 (Champion aXis installation manual, pp. 15, 16, 51; Champion ATS 102009 manual, p. 11)	Not stated	“Programmable start delay” listed as “Standard”, no time	DIP switch 12: 45 s ON, as shipped, or 7 s OFF	Not stated	Not stated	A “cool down cycle”, no time

• Generac’s quick reference table tells an owner whose start delay is longer than expected to “contact an IASD to adjust from 2 to 1500 seconds” (Generac 10–26 kW manual, p. 34). An IASD is Generac’s Independent Authorized Service Dealer. The 10–26 kW manual does not call the 5 seconds a default; the RXS switch manual calls it the “factory default setting” (Generac RXS switch manual, p. 21).
• The two Briggs & Stratton rows are different generations, and neither manual ties the 2013 switch to the 17–26 kW generators, which Briggs & Stratton’s resources page for dealers and installers links under the PowerProtect name (Briggs & Stratton Energy Solutions, “Resources for Dealers & Installers”). The 17–26 kW manual says “The actual system operation is not adjustable and undergoes sequencing by sensors and timers on the controller” (Briggs 17–26 kW manual, p. 24); the GC1030 controller manual lists ranges for those timers, not settings, and prints no defaults for them (Briggs GC1030 manual, p. 9).
• The GC1030 manual lists these timers by name in a parameter table and does not describe what each one does, so their place in the “Start delay”, “Before transfer” and “Return delay” columns follows their names (Briggs GC1030 manual, pp. 8, 9).
• Kohler’s RXT manual says a source “is considered to have failed” below the undervoltage dropout setting and prints the pickup setting, 90% of nominal, without saying in words that it is the level at which the source counts as back (Kohler TP-7193, p. 33). The “Utility back above” column reads it that way.

How long until the lights come back

No document gives one number. Adding what Generac’s 10–26 kW manual prints before transfer gives 10 seconds, a 5-second delay and a 5-second warm-up, or 35 seconds when Cold Smart Start applies, below 50 °F (10 °C) on 10–20 kW and 20 °F (-7 °C) on 22–26 kW, plus a cranking time it does not print for a start that succeeds (Generac 10–26 kW manual, p. 20); a dealer may also have set the delay anywhere from 2 to 1500 seconds (Generac 10–26 kW manual, p. 34). Kohler’s factory delays add up to 6 seconds, plus cranking and the time the generator takes to stabilize (Kohler TP-7193, pp. 11, 38). Generac’s Help Center says transfer “should generally happen within a few seconds, but can take up to 25 minutes if the startup delay has been adjusted”, and in the same article that “a delay of five minutes may occur” (Generac Help Center, “How Do I Simulate a Power Outage to Test My Home Standby System?”, Oct 28, 2025). Briggs & Stratton’s 2013 switch manual says that in its system test the generator starts “After a few minutes”, with no seconds (Briggs ATS 209506 manual, p. 11).

Cranking and a failed start

Model (document)	Attempts	After the last one
Generac 10–26 kW, 10–28 kW and PowerPact (Generac 10–26 kW manual, p. 20; Generac 10–28 kW manual, p. 24; Generac PowerPact manual, p. 17)	Five: 16 s cranking and 7 s resting twice, then three cycles of 7 s and 7 s. The 10 kW in the 10–26 kW manual: 15 s and 7 s, then four cycles of 7 s and 7 s	An alarm
Kohler RCA(L), RESA(L), RESC(L) (Kohler TP-7092, pp. 32, 38; Kohler TP-6804, p. 25)	Three: 15 s crank, 15 s off. With RDC2.4 firmware 1.4.4 or later, two sets of three on the 20 and 26 kW RCA, with a 45-second pause, and on the 20 kW RESA and RESC	Shutdown on an overcrank fault, “Over Crank SD”
Briggs & Stratton 17–26 kW (Briggs GC1030 manual, pp. 8, 11, 19)	Not stated. Controller ranges: Start Attempts 1–9, crank 3–15 sec, rest 2–60 sec	“Fail To Start” alarm
Champion 100515, aXis (Champion 100515 manual, p. 20)	AUTO: 9 s on, 10 s off, 5 cycles. MAN: 10 s, 10 s, 2 cycles	OVER CRANK icon; a 120-second lockout “to allow the starter to properly cool”

Kohler’s Over Crank row tells you to check “the fuel supply, spark plug, and battery” and to contact an authorized dealer (Kohler TP-7092, p. 38). After a Champion over-crank you still wait for the lockout timer to reach zero after pressing OFF, and “The lockout time remaining is not shown on the screen.” (Champion 100515 manual, p. 20).

1. Utility fails: below 65% of nominal, generator set to AUTO

2. Line interrupt delay, five seconds, dealer programmableDisplay: Utility Loss Delay, with a seconds count

3. Utility still gone: engine cranks14–26 kW: 16 s crank, 7 s rest, twice, then three cycles of 7 s crank and 7 s restDisplay: Cranking, Attempt #

   No start after five attempts: alarm

4. Engine warm-up timer: five seconds30 seconds with Cold Smart Start, below 50 °F on 10–20 kW or 20 °F on 22–26 kW

   Utility back above 80% at any time from the start of the engine start sequence until the load transfers: load stays on utility, engine runs its cool-down

5. Controller transfers the load to the generatorGreen Ready LED flashes

6. Utility returns above 80% of nominal for 15 consecutive seconds, dealer programmable

7. Transfers to utility

8. One-minute cool-down, then shuts down

9. Standby in AUTO: green Ready LED on while utility is present

The sequence text names no alarm code for the failed start. The display messages come from the menu map on page 17 and the LED states from page 14; the manual does not draw them on the sequence, and they are placed here by their wording. The menu map on page 17 says: "Menu functions and features may vary depending on unit model and firmware revision."

1. Preferred source fails: below the undervoltage dropout, 90% of pickup

2. Load control contact opens

3. Engine start time delay times outFactory setting: 3 seconds

4. Generator set is signaled to start; it starts and the emergency source becomes available

5. Normal-to-emergency time delay times outFactory setting: 3 seconds

6. Transfer switch transfers to the emergency source

7. Load control time delay times out; the load control contact closesStandard interface board only; fixed at 5 minutes

8. Normal source returns: emergency-to-normal time delay times outFactory setting: 2 minutes

9. Contactor transfers to the normal source

10. Engine cooldown time delay times out

11. Generator is signaled to stop

Page 11 of the manual: the normal source is typically utility power and the emergency source usually a generator set; the sequence calls the source that fails the preferred source, and on page 38 the engine start delay is defined as the time "after utility source is lost". This manual gives no cranking count and no cooldown length; Kohler's generator manual TP-7092 prints both on page 32.

Big loads come back later

Large loads such as air conditioners can be held off for minutes after transfer. On its standard interface board, Kohler’s RXT holds the load control output for a delay “fixed at 5 minutes”, and on its load management board “A 5-minute time delay prevents HVAC loads from adding too quickly” (Kohler TP-7193, pp. 34, 38). Generac’s RXS switch sheds loads “when frequency is less than 58 Hz for three seconds or less than 50 Hz for ½ second (for 60 Hz systems)”, and after a utility loss its four priorities come back between 5 minutes and 5 minutes 45 seconds (Generac RXS switch manual, p. 11). Champion’s load modules “will become active after 5 minutes” (Champion ATS 102009 manual, p. 13). Generac says to contact the nearest IASD “to determine if a load management device is required for your system configuration” (Generac RXS switch manual, p. 10). To compare your loads with a generator’s rating, use the generator size calculator.

The weekly exercise

The controller also starts the engine on a schedule, with no outage. Kohler says regular exercise “is required to keep the engine and alternator in good operating condition” (Kohler TP-7092, p. 33).

Model (document)	How often	How long	House on the generator?	Set from	Skipped or blocked when
Generac 10–26 kW (Generac 10–26 kW manual, pp. 16, 19)	Weekly, biweekly or monthly	About 5 min; with Quiet-Test, at low speed	No, “unless utility power is lost”	Panel or Mobile Link app	Not in AUTO; already running; date and time lost after the battery or fuse was removed, without Wi-Fi
Generac 10–28 kW (Generac 10–28 kW manual, p. 22)	Weekly, biweekly or monthly	5 to 20 min, default 5	Only if Transfer on Scheduled Exercise is enabled, every 3, 6 or 12 months (default Disabled), or with Exercise Now with Transfer	Field Pro app	See Smart Exercise below
Generac PowerPact 7.5 kW (Generac PowerPact manual, p. 15)	Every 7 days	About 12 min	No, unless utility power is lost	SET EXERCISE button, held 3 s in AUTO	Not covered here
Kohler RCA(L) (Kohler TP-7092, pp. 33, 34, 43, 47)	Weekly or every two weeks on the settings screen; “Weekly exercises are recommended.”; the description on p. 33 also names a “new monthly exercise”	20 min: 10 at reduced speed, 3 at full speed, 5 cooling down; a 90-second EcoExercise on the 26RCA/L	No by default; a loaded exercise needs the RXT switch	Controller keypad	Controller OFF; no exercise scheduled
Briggs & Stratton 17–26 kW, GC1030 (Briggs GC1030 manual, pp. 6, 16; Briggs 17–26 kW manual, pp. 24, 32)	Weekly or monthly	Default 0.1 min, 6 s; or 5, 10, 15 or 20 min, or none; an optional 45 min burn-off cycle	No: “Load transfer will not be allowed”	Panel, after the password 0000 printed in the manual	Below 40 °F, skip on by default, and the 45 min burn-off cycle overrides the temperature check; an alarm active; not in AUTO; timer, date or time not set; failed battery; 15 amp fuse
Champion 100515, aXis (Champion 100515 manual, pp. 17, 22, 23, 24, 25; Champion ATS 102009 manual, p. 11)	Off, or 12, 24, 48 or 52 times a year	15 min, “not adjustable”	Not stated	Panel, or the switch’s own Wi-Fi page	Either ON/OFF switch OFF; not in AUTO; DIP switch 11 OFF

Generac’s lengths depend on the model: the 2016 manual for 8–22 kW units gives 12 minutes on the 8 and 11 kW and 5 on the 16, 20 and 22 kW (Generac 8–22 kW manual, 2016, p. 14). Briggs & Stratton’s 17–26 kW manual gives no length or frequency; the row shows what its controller offers.

Skipped exercises and the clock

Of these documents, only Briggs & Stratton’s controller manual prints a cold-weather skip: below 40 °F the exercise is skipped and the controller shows “Auto Exercise Skipped” (Briggs GC1030 manual, pp. 16, 20). Kohler instead recommends monthly EcoExercise cycles “for cold climates” on the 26RCA/L (Kohler TP-7092, p. 34). Generac’s Help Center says some Next Generation models use Smart Exercise, which “may skip a scheduled exercise if the generator has already run recently” (Generac Help Center, “Why is my home standby generator not exercising or exercising at the wrong time?”, Aug 31, 2026); the owner’s manuals do not mention it.

After a battery disconnect, Kohler’s “time, date, and exercise settings will need to be re-entered” (Kohler TP-7092, p. 47) and Champion’s exercise time “MUST BE RESET” (Champion aXis installation manual, p. 55). The PowerPact’s timer “does not correct for daylight saving time.” (Generac PowerPact manual, p. 15).

If the utility fails during an exercise, the outage takes over: a Generac 10–26 kW transfers if the utility stays down five seconds, then switches to AUTO (Generac 10–26 kW manual, p. 16), and in a Kohler unloaded exercise “the ATS transfers to the emergency source, the exercise is ended and the control remains in the AUTO mode” (Kohler TP-7092, p. 35).

What you see and hear

A Guardian display reads “Running - Exercise” during an exercise and “Running - Utility Loss” in an outage (Generac Help Center, “Can I Change the Exercise Cycle Duration?”, Jul 1, 2026); the 10–26 kW manual’s menu map prints the outage message as “Running-Utility Lost” (Generac 10–26 kW manual, p. 18). At Quiet-Test speed the engine “can sputter or run rough” (Generac Help Center, “What Does the Exercise Timer Do on a Home Standby Generator?”, Sep 2, 2025). The same article says a faint gas smell may be noticeable while the unit exercises because some gas goes unburned, and adds: “If the owner smells gas while the unit is shut off, or while it’s powering the home they should contact a dealer or gas company immediately.” Generac’s steps for a suspected leak are under if you smell gas. A Kohler loaded exercise cuts power to the building “for up to 10 seconds during load transfer” (Kohler TP-7092, p. 34).

Generac’s Help Center says “There is no way to disable the exercise”, and that an owner who sets the panel to OFF to stop it risks the warranty unless the unit is exercised manually (Generac Help Center, “What Does the Exercise Timer Do on a Home Standby Generator?”, Sep 2, 2025). OFF also blocks automatic starts in an outage (Generac 10–26 kW manual, p. 15). Champion and Briggs & Stratton both offer a no-exercise setting (Champion 100515 manual, p. 25; Briggs GC1030 manual, p. 6).

Lamps, buttons and modes

Model (document)	Modes	Lamps	Clearing a fault
Generac 10–26 kW (Generac 10–26 kW manual, pp. 14, 15, 16, 34)	AUTO; OFF “prevents automatic operation of unit”; MANUAL starts the engine, transfers only on a utility failure and keeps running after the utility returns “until removed from MANUAL”	Green Ready: on in AUTO with utility, flashing on generator power. Red: OFF or a fault. Yellow: maintenance due	OFF, ENTER, then AUTO
Generac 10–28 kW (Generac 10–28 kW manual, p. 20)	Not covered here	Green Ready: flashes every 2 s during the start delay, every 1 s on generator power	Clearing a Generac code
Kohler RCA(L) (Kohler TP-7092, pp. 36, 42, 43)	RUN skips the start delay; OFF skips the cooldown; AUTO	AUTO lamp; a fast-flashing OFF LED in Auto is a fault shutdown; with an RXT, lamps show which source is available and which feeds the building	Correct the cause, then OFF
Briggs & Stratton 17–26 kW (Briggs 17–26 kW manual, pp. 19, 23, 30)	Auto/Manual button	Solid blue: ready in AUTO. Flashing blue: fault. Dark: MANUAL, no battery power or the ON/OFF switch OFF	Up and down arrows together
Champion 100515 (Champion 100515 manual, pp. 17, 18, 21; Champion aXis installation manual, p. 55)	MAN, AUTO, OFF	BLUE icons during an exercise; a RED icon is a fault and, except LOW BATTERY and MAINTENANCE, shuts the generator down	OFF, then AUTO; the installation manual says OFF for 10 s, then the previous mode

What an owner can do, and what goes to a dealer or electrician

The owner’s part in these manuals:

• Keep the controller in AUTO, and set the date, time and exercise schedule again after the battery has been disconnected.
• Clear an alarm as the table above shows, and call the dealer if it comes back. Generac: “an owner can clear the alarm and restart generator prior to contacting an IASD” (Generac 10–26 kW manual, p. 10). Kohler: “Always identify and correct the cause of a fault shutdown before resetting the controller.” (Kohler TP-7092, p. 36).
• If a Generac runs in AUTO but the house is dark, check the generator MLCB (generator disconnect), and call an IASD if it is ON (Generac 10–26 kW manual, p. 34).
• On a Champion, check the exterior warning LED weekly (Champion aXis installation manual, p. 55).
• Keep carbon monoxide alarms indoors; Briggs & Stratton calls that “the owner’s responsibility” (Briggs 17–26 kW manual, p. 4).

For the dealer, the installer or a licensed electrician:

• Installation. Generac: “Only a trained and licensed electrician should perform wiring and connections to unit.” (Generac 10–26 kW manual, p. 2). Briggs & Stratton: “Only current licensed electrical professionals are qualified to do system installations.” (Briggs 17–26 kW manual, p. 5). Kohler: “Only trained and qualified personnel should install or service the transfer switch and accessories.” (Kohler TP-7193, p. 8). Champion’s fleX switch “must be installed by a qualified electrician” (Champion fleX ATS manual, p. 4).
• Time delays. Generac marks them dealer programmable (Generac 10–26 kW manual, pp. 16, 20). Kohler’s RXT manual leaves them to an authorized distributor or dealer with SiteTech software (Kohler TP-7193, p. 38), while its RCA manual says to use the controller’s ATS Configuration submenu to check the switch’s time delays “and change the settings, if necessary” (Kohler TP-7092, p. 57); the two do not settle who may. Briggs & Stratton: “Certain parameters can only be changed by the dealer while others can only be changed by the manufacturer” (Briggs GC1030 manual, p. 14). Champion’s delay before the generator accepts load is DIP switch 12 inside the switch, and its installation manual says “Verify the DIP switches are set for your installation. Adjust as needed.” (Champion ATS 102009 manual, p. 11).
• Gas. Generac: “Connection of fuel source must be completed by a qualified professional technician or contractor.” (Generac 10–26 kW manual, p. 3). Briggs & Stratton’s fuel installation “must be performed by a licensed professional” (Briggs 17–26 kW manual, p. 12). The Champion manuals here do not say who connects the gas.
• Service. Generac “recommends that all maintenance work be performed by an Independent Authorized Service Dealer (IASD)” (Generac 10–26 kW manual, p. 22), and Kohler asks for a dealer inspection of the switch annually (Kohler TP-7193, p. 7).

A test that cuts the utility on purpose is written for owners in Generac’s Help Center, which says to run it at least 30 minutes (Generac Help Center, “How Do I Simulate a Power Outage to Test My Home Standby System?”, Oct 28, 2025). Briggs & Stratton’s 2013 switch manual, an installation and operator’s manual, gives the same test under System Test, with the service disconnect feeding the switch turned off, and asks for the exercise at least once every three months; it does not say who runs it (Briggs ATS 209506 manual, pp. 11, 12). Kohler asks for a monthly test in its installation section without saying who runs it (Kohler TP-7193, p. 31), and lists “Test the transfer switch’s automatic control system” among the scheduled maintenance that an authorized distributor/dealer performs (Kohler TP-7193, p. 42). Champion recommends “a licensed electrician or an individual with complete knowledge of electricity” for its no-load and under-load checks (Champion aXis installation manual, pp. 50, 51). If your manual does not give the test to the owner, leave it to the dealer or an electrician.

Backfeed and carbon monoxide

Generac: “Electrical backfeed. Use only approved switchgear to isolate generator from the normal power source.” (Generac 10–26 kW manual, p. 3). Kohler: “Electrical backfeed into a utility electrical system can cause severe injury or death to utility personnel working on power lines.” (Kohler TP-7092, p. 11). Champion warns of “utility power workers who may receive electrical back-feed from the HSB” (Champion aXis installation manual, p. 48). The Briggs & Stratton documents here do not use the word backfeed; the 17–26 kW manual requires a Nationally Recognized Testing Laboratory (NRTL) approved transfer switch “that is compatible with the generator” (Briggs 17–26 kW manual, p. 4).

Each of the four brands warns about carbon monoxide. Generac: “Running engines produce carbon monoxide, a colorless, odorless, poisonous gas.” (Generac 10–26 kW manual, p. 2). Briggs & Stratton: “You cannot smell it, see it, or taste it.” (Briggs 17–26 kW manual, p. 24). Kohler: “Carbon monoxide can cause severe nausea, fainting, or death.” (Kohler TP-7092, p. 29). Champion: “Breathing carbon monoxide (CO) will cause nausea, dizziness, fainting or death.” (Champion 100515 manual, p. 5). Distances from the house are on the generator clearances page.

For a suspected gas leak, Generac’s steps are under if you smell gas; its advice on a gas smell during an exercise is under “What you see and hear” above.

Generac codes and related pages

• Generac: 1100, overcrank; 2800, emergency shutdown switch is off; 2750, low battery; 2100, overload; 1600, underspeed; 1300, low oil pressure; 1400, high temperature; 1500–1521, RPM sense loss; 1900–1906, undervoltage; all Generac codes, status LEDs and how to clear a code
• Placement: generator clearances by manufacturer
• Sizing: generator size calculator
• Before winter: the winter checklist covers Generac’s exercise settings, cold weather kits and snow at the louvers.

What these documents do not cover

• A total time from outage to power, or how long the house is dark during transfer in a real outage. Kohler prints “up to 10 seconds” only for its loaded exercise.
• Briggs & Stratton 17–26 kW: no seconds for its timers, no exercise length or frequency in the generator manual, and no transfer switch manual for these units found on a Briggs & Stratton host. The GC1030 manual prints ranges, not defaults.
• Champion: no start delay, return delay or cool-down time for the aXis system. The 22 kW 100304 operator’s manual and the other aXis switches were not read.
• Kohler: factory delays for the Model RXT only. The Model RDT, OnCue and newer revisions on the Rehlko site were not checked.
• Generac: the RXS switch manual prints no cranking time and no total time from outage to power. Generac’s other switches and its liquid-cooled models were not read.
• NEC article 702 is not covered; the CPSC and CDC carbon monoxide guidance is on the clearances page.
• Each time here belongs to the model and revision named with it. Check your own manual, and ask your dealer what delays were set at installation.

See also

• Generator size calculator
• Generator clearances: how far from the house, by manufacturer
• Home maintenance schedule from the manuals: monthly to yearly
• Winter home maintenance checklist: furnace, boiler, water heater

Error codes: Generac