If I remember correctly LM3914 has input range (pin 5) 0-5VDC.
Divider 22k/1.5k would expand this to ca. 0-80V. With ca 20V dropped
on Zener diodes, range would shift from 0-80V to 20-100V.
So LEDs would turn on 28, 36, 44, 52, 60, 68,76, 84, 92 and 100V.
At 100V at the input zener diodes and 1k/1W will be overloaded.
For example at 80V drop on 1k, resistor would have to have to
sweat ca 6.4Watt and with only 1W rating it would certainly smoke...
If you get rid of zeners and 1W resistor and change 22k/1.5k divider
to 22k/2.2k for example, you would get linear scale 0-50V with LEDs
turning on 5, 10, 15, 20, 25, 30, 35, 40, 45 and 50V.
For more detail get the datasheet and read it. you will also find sample circuits.