Generator Start Up
May 11, 2021 Jeff Rosenblum
Generator sales are up due to the storms and while the installation is fairly straight forward, the start up is sometimes neglected. Here we discuss how to properly start up an air cooled home stand by generator.
After the generator is installed, a start up is required. The first thing to do is install a manometer on the gas regulator inside the generator and get a "static" pressure reading. Gas pressure should be between 5-7" wc. If the pressure is below this, some steps may be required to ensure there is adequate gas supply for the unit to run.
Next, ensure the main breaker for the generator is open and start the generator by presssing the manual run button. Observe the gas pressure. If it drops below 1"wc then there may be an issue with fuel line sizing or an issue with the main regulator. While the generator is running, check the voltage from the generator at the main breaker. It should be line voltage. Also verify the frequency. In the USA it should be 60hz.
Once the voltage, frequency and gas pressure are verified load testing is next. Place the generator into the auto mode. Open all breakers from the panel. Open the main disconnect for the house and observe the operation. The generator should start within 20 seconds and the transfer switch should transfer over 10 seconds after that. With the generator running, slowly start introducing the loads by closing the breakers. With all breakers closed start turning on all lights and low load appliances. Continue to observe the gas pressure, voltage and frequency.
Next, turn on all large high demand loads. The generator should be sized to handle all loads or if using load sheding, it should start to shed the large loads. If the generator shuts down during this test, the generator may not be sized correctly for the house.
The final step is to close the main service disconnect to the house and the transfer switch should switch over to city electric. The generator will run for an additional couple minutes to cool off. Remove all tools, set the exercise time and explain the operation to your customer.
As always if you need any additional help please call the Famous Supply HVAC Tech Department at 800-362-8230.
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