Your Supplier Wants To See You In Their Office? Read this!

If a supplier summons you to their office because of failing units you supply, do not panic. There are high chances that it is something fixable or something that the buyer is doing wrong.

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AC generator failure is not a simple matter. If you experience frequent power blackouts, you want your GenSet to be ready all the time.
Most customers do not understand how their diesel AC units work. Thus, when it fails, they panic. They are unable to troubleshoot and isolate the problem.
You are an agent representing a manufacturer. Is your supplier getting many complaints from their customers about your generators failing? They will demand an explanation from you.
If an angry supplier summons you, don’t panic. A GenSet failing does not always mean it is faulty. There are many reasons for the AC pieces failing to start or not doing their job to completion.
Keep reading to see all the possible reasons for this failure:

5 Main Reasons Why an AC GenSet Fails

If a buyer knows the leading causes of motor failure, they can also learn how to avoid such losses.
Here are some of the most common causes of your diesel backup unit not working as it should:

1.Lack of fuel or fuel system problems

When a unit dies, you have to start with the simplest checks. If you hardly use it, the thought of topping up the fuel tank might escape you from time to time.
Thus, every time that you run the set, it consumes a little. It does this until there is no fuel left in the tank.
If you do not check the tank, you will start the unit one day, but it will not run because it will be diesel.


Fuel leakage

If there is a fuel leak and the diesel seeps into the soil, you might not know that your set is out of fuel. Thus, it will run only as long as the remaining energy will last when you start it.
If there is a fuel leak, you need to fix it before you can top up the diesel. Usually, a broken fuel line will cause leakage. But it could be anything else. Do not rule anything out until the technician spots and stops the leak.

Faulty fuel gauge

Modern Gen-Sets come with a display panel. It shows the fuel level and other important information. But at times, the fuel gauge might fail. It could display the fuel tank status as full or three-quarter complete, while in the real sense, it is empty.
In this case, you might have to check the fuel tank to establish that, indeed, there is fuel.
If your unit has a mechanical fuel gauge, it might fail to work if you have not run it for a long time. Mechanical gauges must vibrate so that they can start working.

Faulty fuel pump

Sometimes, the GenSet might have enough fuel and still fail to work. This is where you need to troubleshoot a few things.
Start with the fuel pump. If the pump is not working, it will not pump fuel where to the cylinders.
The fuel pump draws the fuel from the tank. It then sends the energy through the fuel line to the fuel rail.
Some nozzles inject fuel into the cylinders in the fuel rail, where it will mix with air. A spark then ignites the mixture to produce power.
From all the parts that we mention here, you can see that the fuel system is complex. If any component fails, the unit will definitely fail.

2. Battery failure due to sulfation build-up

This is one of the reasons why your backup appliance will fail to start up from time to time. Thus, if you crank up and fall to roar to life, you need to check the battery.
One of the leading causes of battery failure is that it builds upon the terminals and lead plates. If the batteries do not have a charge, your unit will fail to start. But this is not always the case, as diesel units have alternators, which charge the batteries.
Once you are cleaning out what builds upon the terminals, you will solve the problem. It is better to prevent the build-up rather than wait for the problem to occur. Prevention is always better than cure.
Sulfation builds up on the terminals and lead plates of the lead-acid batteries. Usually, this happens because the battery water (electrolyte) has sulfur molecules.
The battery discharges these molecules. They attach to the lead plates of the storm. If they cover the entire lead plate, the battery will not be able to provide current.

diesel generator set

3. Shut down due to high temperature

AC generators can also fail after generating high temperatures. Some units come with a low coolant alert, and some do not have it.
When your AC diesel unit has low or no coolant, it will shut down after getting too hot. This is a built-in safety measure that protects the team from damage.
In most cases, if the unit shuts down due to running a high temperature when it cools down, it can start working again. If you notice this kind of behavior, check the coolant levels.
If yours has a low coolant alert, pay attention to it. Also, if it has an app, download it. You can check the performance of the appliance even when you are traveling.
When you do not have the means to check the unit’s performance, check it for leaks in person, or send someone.
Usually, diesel AC units run out of coolant because it is leaking. These can be small, persistent leaks that you overlook.
As time passes, though, the coolant level runs low, and then your unit starts to fail.
Check around the unit for spilled coolant. Usually, coolant has a reddish color. It is hard to miss it. If it spills and seeps into the soil, you will see telltale signs from the wet ground.
Usually, to prevent the unit from shutting down, you will need to top up the coolant. But you cannot do that before you know where it is leaking.
Check for worn-out hosepipes. This is usually the first cause. If the hosepipes look fine, check the radiator cap. If it’s worn out, it might not hold the pressure well.
Once you know the root cause of the coolant leak, repair it and top it up. You will find that the gen runs well after that.

4. Wrong Control Settings

This is another common cause of your diesel unit failing to work. After servicing your team, the technician might forget to enter the correct settings.
If the unit is new and you enter the wrong settings, it might fail to work. Usually, customers will call the supplier to lodge complaints.
If your unit self-starts when the main grid power goes out, it has to be in the on position all the time.
But after servicing, the technicians might forget to reset the unit. They might also leave the main switch in the “off” position. Thus, the team is not going to start automatically when there is a power blackout.
It is simple to avoid such simple goofs. Always check the settings yourself after the technician completes the servicing.
A unit might go through an error shutdown, for example, from a high-temperature shutdown.
Once you repair the coolant problem, you might forget to enter the correct settings again. This will cause the unit not to work.

Control for Diesel Genset

5. Neglecting Maintenance

Lack of proper maintenance for your diesel generator causes unexpected shutdowns.
You might be servicing the set on time. Yet, you might also be using components of low quality. You must use the right oil, fuel filter, air filter, and oil filter.
Even when you do not run your unit, it’s essential to maintain a regular maintenance schedule. The fuel, coolant, and oil stay stagnant in the tank. This might affect the usability and the quality of the fluids.
Thus, if you stay too long before running the unit, it would be better to pour out all the fluids and top them up with new ones.
Lack of regular maintenance has many downsides. You will not know the status of essential parts such as hosepipes, fuel systems,s, and others.
Some of these parts are cheap to buy and easy to replace. But if they are faulty, they can stop the entire operation of your diesel unit.
When selling the generator, suppliers will give the buyer the maintenance information. Also, the manufacturer’s warranty has all the requirements and maintenance procedures.
But many buyers always neglect this vital information. For example, poor soil quality may lead to error shutdowns until one uses the proper oil.


Choosing the best generator is the first step to subsidizing your power bill. It also keeps your home or business running when there is a blackout. But to keep your diesel unit running, you also need to maintain it.
Many customers do not understand how to run regular checks on their generators. Thus, when theirs fails, they contact the supplier. The supplier, in turn, reaches you and asks why your units have manufacturing defects.
When the diesel unit is still new, it requires some time to figure out how it works, the correct settings to enter, and so on.
Thus, buyers with new units may not know how to operate them. They could call the supplier to complain that their new GenSets are failing.
If a supplier summons you to their office because of failing units you supply, do not panic.
There are high chances that it is something fixable or something that the buyer is doing wrong.

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Hey all, I'm Baymax Yan, working at a generator manufacturer and Having more than 15 years of experience in this field, and I belives that “learn and lives.” The sure thing is that I can often help my work. So I have created the blog to share all my knowledge with you. Hope my sharing helps!

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