Gas Generator Power Systems for Spray Foam

The gas generator is the power foundation of a gas spray foam rig. Generator selection affects heater performance, electrical stability, and the contractor's ability to power additional loads alongside the machine.

Generator sizing for gas rigs:

• The proportioner heater package is the primary electrical load. Common heater packages:
• Graco Reactor A-25: approximately 7.5–10 kW heater demand
• Graco Reactor A-30: approximately 7.5–12 kW heater demand

Generator output should exceed heater demand by at least 5–8 kW to provide headroom for stable heater performance under sustained load. A machine with a 10 kW heater should be paired with a 20 kW+ generator.

• Additional loads:
• Refrigerated air dryer: typically 0.5–1.5 kW
• Interior lighting: typically 0.5–1 kW
• Wall heater (cold weather): typically 1.5–3 kW

Generator quality matters. A 20 kW generator from a quality manufacturer provides more stable voltage output than an off-brand 20 kW unit. Voltage sag under load — where output drops below rated voltage — affects heater element performance.

Maintenance intervals: Gas generators require oil changes, filter replacements, and valve adjustments more frequently than diesel generators. Include generator maintenance in the rig maintenance schedule.

Shore power inlet: Allows trailer systems to operate overnight from external 120/240V power without running the generator. Important for cold-weather chemical conditioning.