Dean MF90 Series Parts Manual page 11

6.3 FILTER PUMP FAILS TO PUMP OIL?
Filter
pump
fails to
pump
oil.
If filter unit has a
heater, turn heater
ON and allow to
heat for 20
minutes.
Disconnect flexible oil return
hose. Make sure it is cool before
handling. Try blowing air through
the hose.
Can you blow
air through it?
Yes
Insert flexible oil
return hose into
filter pan and turn
pump motor ON.
Does oil flow through oil
return hose?
Yes
Proceed with normal
operations.
Submerge hose in very hot water,
keeping the water out of the hose.
No Water in the hose will cause severe
splattering when ho oil is run
through the hose.
Once shortening has had time
to soften, reconnect hose to
filter pump.
Insert hose nozzle
into pan holster,
and turn pump
Blockage is between bottom of the filter
No pan and the flexible hose quick
disconnect. Go to Section 6.5.
10
ON.