This article is designed to give an overview of how to flush your Graco/Gusmer/Glascraft equipment of polyurethane foam chemicals or polyurea/polyurethane/hybrid chemicals as part of a regular maintenance schedule or prior to storage of the spray equipment.

We recommend all applicators follow this procedure every 6 to 12 months. Once started you will need to finish the flushing procedure, be sure to allow for the time needed to complete the procedure start to finish.

01Follow your equipments Pressure Relief Procedure before cleaning, checking, or servicing equipment. Disconnect hoses from gun.

02We will begin by air purging all of the material from the Resin side of the system.

03Close the transfer pump air line needle valve, disconnect the air line from the Resin transfer pump and remove the pump from the material drum. If possible lift the inlet ball to drain the material from the transfer pump. Wipe the exterior of the pump with a clean rag.

04Insert the Resin transfer pump into an empty pail and secure to prevent tipping. Reconnect the air line.

05Using just the transfer pump slowly open the transfer pump air line needle valve and purge the material back into the drum the material came from (This will purge all the Resin from the system and fill the system with air allowing us to save most of the material in the system). Once all material has been purged from the system close the transfer pump air line needle valve and disconnect the air line on the Resin transfer pump.

06We now need to repeat this procedure (Steps 3 – 5) to purge all of the material from the Iso side.

07Now that the fluid has been air purged from the system we can start the cleaning procedure. Fill two separate 5 gallon pails with 2-4 gallons of All-Solve (1 pail for the (A) Iso side and 1 pail for the (B) Poly side). All-Solve is especially effective for cleaning the proportioner, transfer pumps and hoses, as it quickly and completely cleans polyols, crystallized isocyanates, and other urethane intermediates.

08Insert each transfer pump into separate 5 gallon pails of All-Solve and secure to prevent tipping the pails. Reconnect the air lines. Slowly open the transfer pump air line needle valve and fill the system with All-Solve. Purge the first 1/2 gallon of material per side into a waste pail. Safely dispose of the waste materials in accordance with federal, state/provincial and local regulations.

09Once the proportioner has been filled with All-Solve you can turn on the proportioner and set the primary and hose heaters to 150° F and turn on the heaters (Do not attempt to pressurize the system).

10Securely fasten the material hose ends to their respective pails of All-Solve, use a filter/screen under the material hose ends if you suspect debris to be in the system, open the transfer pump air line needle valve and allow the All-Solve to recirculate through the system for 2-4 hours or longer depending how much scale has built up on the inside of the system.

11Once the cleaning procedure has finished we will need to air purge the All-Solve from the system.

12Insert the transfer pumps into an empty pail and secure to prevent tipping. Reconnect the air line.

13Using just the transfer pump slowly open the transfer pump air line needle valve and purge the All-Solve back into the 5 gallon pail it came from (the All-Solve can be saved and used again to flush the system at a later date).

14Once all the All-Solve has been purged from the system close the transfer pump air line needle valve and disconnect the air line from the transfer pump.

15Wipe the exterior of the transfer pumps with a clean rag. Insert the transfer pumps into their respective material drums and secure. Reconnect the air lines.

16Slowly open the transfer pump air line needle valve and fill the system with Iso and Resin. Purge the first 1/2 gallon of material per side into a waste pail. Safely dispose of the waste materials in accordance with federal, state/provincial and local regulations.

17Re-attach the spray gun to the hoses, turn on the proportioner, set the temperatures and pressures according to the material specifications.

18Spray onto piece of cardboard or other disposable surface to insure material is spraying and curing correctly. You are now ready to spray.

15Fill two 5 gallon pails with 2-4 gallons of Pump Fluid, a highly refined, special purpose lubricant that can be used for equipment flushing, equipment storage and throat seal lube.

16Wipe the exterior of the transfer pumps with a clean rag. Insert the transfer pumps into separate 5 gallon pails of Pump Fluid and secure to prevent tipping the pail. Reconnect the air lines.

17Slowly open the transfer pump air line needle valve and fill the system with Pump Fluid. Purge the first 1/2 gallon of material per side into a waste pail. Safely dispose of the waste materials in accordance with federal, state/provincial and local regulations.

18Securely fasten the material hose ends to their respective pails of Pump Fluid, open the transfer pump air line needle valve and allow the Pump Fluid to recirculate through the system for 15 minutes.

19Re-attach the spray gun to the hoses, turn the proportioner on and increase pressure to 1000 psi. Trigger spray gun until pump is in the park/retract position and pressure falls below 500 psi.

20Insure all valves are closed and power is off. Remove and clean spray gun. The proportioner can now be safely stored.