Table 5-3. Direct and General Support Maintenance Troubleshooting (Continued)
TEST OR INSPECTION
FORMULATION TANK WILL NOT HOLD PRESSURE (Continued)
Remove the filler cap and inspect it.
BE SURE to open the pressure drain valve and release the tank pressure before removing the filler
If the filler cap is warped or dented so the cap will not seal correctly, replace it and go to Step 4c.
If the O-ring is cracked, broken or swelled, replace the cap and go to Step 4c.
Close the pressure drain valve and pressurize the formulation tank. Let it sit for 5-10 minutes.
If the formulation tank holds 11-14 psi pressure, the problem is solved.
If the formulation tank does not hold 11-14 psi pressure, go to Step 5.
Check the pressure drain valve for air leaks.
Start the engine and pressurize the tank. When the tank pressure reaches 11-14 psi, shut the engine
Remove the pressure drain hose from the retaining clip and place it in a container of water.
BE SURE to open the pressure drain valve and release the tank pressure before replacing it.
If a steady stream of air bubbles form in the water, replace the valve.
If no air bubbles form, the valve is ok. Go to Step 6.
Check the welded seams on the tank for air leaks.
Start the engine and pressurize the tank.
Test the welded seams.
Prepare a thick lather with soap and water.
Spread the lather over the welded seams.
If there are any leaks, they will blow bubbles through the lather. Go to Step 6c.