Replacing an old inlet fitting

[DivingIn]

I need to replace an old chrome inlet fitting in my vinyl in-ground pool. I am planning to us a Hayward SP1408 fitting. The directions say the pool wall thickness must be equal to or below 1/4" or between 5/8" and 1". I don't have it all apart yet, but I think my wall thickness is 1/2". Why wouldn't the fitting work? Why does it have those restrictions?

Also, if I discover that the existing hole in the pool wall is less than 3", I will have to make the hole bigger. Would I use a hole saw for that?

 

[ajw22]

@1poolman1 you familiar with this fitting?

 

[1poolman1]

@1poolman1 you familiar with this fitting?

Not a lot of vinyl pools in my area, but portable spas are similar. The wall-size limits are because that is the range of what the fitting can seal against, its only so big. Trying to enlarge an already existing hole with a hole saw is tricky at best above ground, on a pool wall you need to be very careful not to damage yourself, the liner, the wall. And, of course, you would use battery-operated tools. May be a job for a pro.