Top 9 Reasons - Generator Not to Start
In the result of a power failure standby diesel generators are there for us when we need them the most… at least that’s what we hope. As with any piece of machinery a diesel generator cannot be 100% reliable, You would know from this blog Top Common Top 9 reasons why a diesel generator may fail to start and most importantly, how to maintain and repair a diesel generator to reduce the risk of a failure.
what can cause a diesel generator not to start?
Standby diesel generators are often operated infrequently, meaning that monthly tests and scheduled service plans are vital to ensure faults are not occurring unknown to the operator. Let’s take a look at what can cause a diesel generator not to start and what you can do to prevent these happening in the future.
Check the following:
1, Dead Start Battery or Battery Switch Fault
One of the most common reasons a diesel generator not to start is due to a start battery failure. Often this could be caused by a loose connection or battery undervoltage. At METCL diesel generator, we use 12V maintenance-free lead-acid batteries as a start battery.
A start battery failure can also occur due to the charger breaker being open inoperable, usually by a fault within the battery charger unit itself or the AC supply being disconnected by a tripped circuit breaker. This can often happen after a service or maintenance has been carried out when the charger has been turned off and not turned back on again. It is always worth double-checking the generator system after a service or maintenance has been carried out to ensure the charger supply circuit breaker is in the correct position.
At METCL diesel generator, a start battery switch is designed and installed to protect personnel safety, Please Ensure the start battery switch at ON position before starting the generator, at OFF position after the generator stop to enhance battery life. we recommend you replace your diesel generator start batteries every 2-3 years to reduce the risk of failure.
2, Is the Diesel Generator System Power Switch ON or Failure?
The diesel generator system power switch supplies power to the generator controller and lighting. At METCL diesel generator, there is a power switch installed at the control panel. Switch ON the power switch before the diesel generator starts, the generator controller will be powered ON after the power switch is ON, and then you can manually or auto-start the generator via the generator controller
3, Is the emergency stop button at the Initial OFF position?
In case of any emergency situation occurs an emergency stop button is vital to ensure machinery and personnel safety. A wrong Emergency stop button position can also cause a diesel generator not to start due to the emergency stop button cutting off the fuel supply, usually by a faulty emergency stop button unit itself or at the ON position, This can often happen after a misoperation. It is always worth double-checking the generator system after a service or before the diesel generator starts to ensure the emergency stop button is in the correct position.
4, Is the Intermediate Relay inside the control panel working?
The start intermediate relay which connects with DC 12V/24V start relay at the start motor is used for the protection of diesel generators requiring reverse power protection, high-set and low-set overvoltage protection, high-set and low-set overcurrent protection, and directional earth-fault protection. What can cause a diesel generator not to start? The fault start intermediate relay is also a common reason for the generator not to start. After the starting battery and power switch is ON, try to manually start the diesel generator via the generator controller, Open the control panel to check the start intermediate relay if the diesel generator not cranking.
5, Start Relay (Solenoid) Fault
What can cause a diesel generator not to start? The fifth reason is the Start Relay, a 12V or 24V start relay commonly installed with a start motor, it is used to protect the circuit and supply start motor power, it is essentially an overcurrent protection device that limits overcurrent in the circuit. After manually starting the diesel generator via the generator controller, please check the start relay if the diesel engine no cranking. Replace for a new start relay if necessary.
6, Start Motor Fault
What can cause a diesel generator not to start? The sixth reason is the Start Motor (Rarely occurs). The electric starter motor is the most common type used on diesel generators. The modern starter motor is either a permanent magnet or a series-parallel wound direct current electric motor with a starter solenoid (similar to a relay) mounted on it.
7, Low Coolant Level or Coolant Temp Sensor Fault.
What can cause a diesel generator not to start? The seventh reason is the low coolant level. Without radiator coolant, a diesel engine would soon overheat, leading to mechanical breakdown and engine failure. Coolant levels should be checked on a regular basis by visually checking if there are any puddles of coolant. The coolant color varies depending on the manufacturer although it most commonly will look red.
Internally plugged radiator cores can also lead to low coolant level shutdowns. When the generator is operating under load, the thermostats open completely when the engine reaches the optimum operation temperature, meaning the radiator cannot allow the proper amount of flow through the core. Because the coolant has to go somewhere, it escapes through the overflow line. When the engine cools off and the thermostat closes, the level drops and activates a low coolant level shutdown to your generator. Because this only happens when the generator has reached to optimum running temperature under load, it is suggested that you test your generator with an external load bank with sufficient load to reach the temperature value needed to open the thermostats.
8, Low Lube Oil Level or Lube Oil Pressure Sensor Fault.
What can cause a diesel generator not to start? The eighth reason is the low lube oil level. The low lube oil level will cause low lube oil pressure alarm, at METCL diesel generator, the manual/auto generator controller with low oil pressure alarm and protection will not start the generator.
9, Lack of diesel fuel supply
What can cause a diesel generator not to start? Lack of diesel fuel supply is a common reason. There may exist some air in the fuel supply line mostly happening at the first generator starting or long-time no running. This causes the diesel fuel to drop back and not enter the diesel engine body. bleeding the diesel fuel to the diesel engine by manually pumping fuel or turning the primary bleed screw. Check your generator manual for its location. Then gently turn the screw to allow the air to escape and then re-tighten once fuel begins to appear at the screw.