Outside oil tank installation with Granby fiberglass tank, Haseloh Fuel Oil Safety Valve, Tigerloop de-aerator, material, labour and disposal of old tank. Don't just upgrade on the tank, the oil line is vulnerable too. The Haseloh OSV prevents oil loss if your oil line is damaged or vandalised. This include leaks in filters, filters and fuel pump. The OSV is installed in the tank and not inside by the burner, as is the case with other OSVs.