Applies to:

Troubleshooting Oil Not Pumping

Overview

Why will oil not return from filter pan, and pump does not have suction at pickup tube/plug and play?

Units with solenoid return valves have a high pressure inline bypass check valve on the pump's discharge side. The bypass check valve is designed to open at pressures greater than 35-40 psi and creates a return loop to the pump's suction side. If the bypass check valve sticks open, then the filter pump system will have little to no suction at the pickup tube/plug and play.

Units with a selector valve have the bypass check valve is part of an elbow fitting, and not an inline type as described above. The bypass check valve elbow fitting is designed to open at pressures greater than 50 psi and is installed in one of the four large selector valve ports which are common to the pump's discharge side.

Procedure

To test the filter pump system:

Remove the filter pan and white return hose discharge end from fryer.
Energize the filter pump to see if air will flow through the hose.

If testing with oil from an inserted filter pan, energize the pump to see if oil will return to the filter pan or a metal container.

If air or oil flows through the white return hose, then the bypass check valve may be stuck open.
Clean the high pressure bypass check valve.
If air or oil continues to flow through the white return hose, replace the high pressure bypass check valve.

Refer to plumbing diagrams.