Dean D50 Installation, Operation & Maintenance Manual page 25

6.5.4 Blockage between Filter Pan and Flex Hose Valve?
Blockage is
suspected between
filter pan bottom and
flex hose disconnect.
Disconnect oil line from
filter pan to pump at the
pump end.
Turn pump ON and allow it to
operate for a few seconds to ensure
it does not run backwards.
Put your finger over the
pump inlet. Is suction
present?
Yes
Pump is clear; plug is
in the bottom of the
filter pan or in the line
from the pan to pump.
Disconnect line at filter pan.
Can you blow air through line
from pump to pan?
Yes
Reconnect line and
operate pump. If still
no oil flow, blockage
is in bottom of pan.
No
Line is blocked. Remove
line, soften and clear
No
solidified shortening.
24
Blockage is in pump or in
the discharge line.
Remedy problem and continue
filtration process.