Can you please answer the following.
1. Per CAT Application and Installation guide for Diesel Fuels and Diesel Fuel Systems From Page 21: Note:Shut-off valves should not be used in fuel return lines. Engine operation with the valve closed will cause damaging pressures.
The end user prefer to add isolation ball valves on the return line. Is it acceptable per NFPA 37?
2. From NFPA 37-2018 18.104.22.168 The overflow line shall be continuous piping, without valves or traps, back to the source tank or to a collection system. Is this applicable to fuel oil return line too?