Is it acceptable to substitute filter "B" for filter "A"?
Substituting filters simply because they are similar in size is not good practice. Although filters may appear to be the same, the internal components, including the filtering media, may be completely different. Use of a filter not designed to protect the equipment it is being used on could cause damage to the equipment.
So why would it hurt to substitute a filter one time only? If we substitute filter "B" for filter "A", it is likely that when the equipment is serviced the next time, filter "B" will be removed and another filter "B" will be used to replace it. It is likely that filter "B" will become the filter used on that equipment from that point on.
For all filter applications, see our catalog cross-reference or application guide to determine the correct filter to use for your application.