The oil re turn valve is clog ged
Clean the oil re turn valve
(see “Main te nance, Oil change/Oil Fil ter, Oil
Re turn Valve clea ning”)
The oil re turn line is clog ged or bro ken
Re pair the oil tu bing (Busch ser vice)
Re place a bro ken oil re turn line with an iden ti -
cal ly di men sio ned line
Fill in new oil
The oil is black
Oil change in ter vals are too long
The oil was over hea ted
Flush the va cuum pump
Re place the oil fil ter(d)
Re place the ex haust fil ters (l)
Fill in new oil
(see “Main te nance”)
In case the oil life is too short: use oil with
bet ter heat re sis tance (see “Oil”) or re tro fit
co o ling
The oil is wa te ry and co lou red white
The va cuum pump as pi ra ted wa ter or si gni fi -
cant amounts of hu mi di ty
Flush the va cuum pump
Re place the oil fil ter(d)
Re place the ex haust fil ters (l)
Flush the va cuum pump
(see “Main te nance”)
Mo di fy the ope ra tio nal mode
(see “Instal la tion and Com mis sio ning, Ope ra -
ting No tes, Con veying Con den sable
Vapours”)
The oil is re si nous and/or stic ky
Impro per oil type, per haps in confu sion
Flush the va cuum pump
Re place the oil fil ter(d)
Re place the ex haust fil ters (l)
Fill in new oil
(see “Main te nance”)
Make sure the pro per oil is used for the ap pli -
ca tion
The oil foams
Mixing of in com pa tible oils
Flush the va cuum pump
Re place the oil fil ter(d)
Re place the ex haust fil ters (l)
Fill in new oil
(see “Main te nance”)
Make sure the pro per oil is used for the ap pli -
ca tion
Troubleshooting
Page 18
