What is the benefit of preheating material before the pump on the low-pressure side?

When the material in the drums is too cold, spraying foam can be hard. The job takes longer, the foam can start to pop or shrink, and breakdowns occur more often. Preheating the material before the pump on the low-pressure side will help ensure efficient spray foaming and high-quality spray results.

When spraying foam or polyurea, the quality of the spray result is determined by many aspects, including temperature. The ambient temperature and the temperature of the substrate influence the result of your finished spray product– and the temperature of the material plays an important role too.

Note: Some foam blowing agents will froth at temperatures above 33°C (90°F)  when not under pressure. Consult with your material supplier regarding fluid temperature limits for preheating  the materials. 

Benefits of preheating materials

Material that is too cold can lead to uneven foam distribution, with foam that tends to pop, shrink, or spatter. To avoid bad spraying results, you can preheat the materials before the pump. This enables:

• a more efficient heating capacity
• better material viscosity

Optimum heat transfer is achieved when the fluid flow rates and temperature set points are achievable based on the size of the motor and heater on your proportioner.

When your materials and your system operate with optimum heat transfer, all spraying jobs are more efficient and produce better results.

How can you preheat the materials?

You can preheat the materials in the drums by activating “Jog mode” on the Advanced Display Module (ADM) of your Graco Reactor and circulating fluid through the system. More information and proper Reactor setup can be found in the Graco Reactor manuals (3A1569 – 334945 – 333023).

Note: Do not recirculate closed cell foam with the 245FA blowing agent

Refer to the manual for further directions: