Trying to replace a 8045-20 w/ 8145-20 need wiring info

The 8045-20 & 8145 are 240V timers.
My maintenance buddy at McDonalds says the defrost timers are interchangeable, BUT I have not wired these particular timers.
You may want to post your question to a paid answerer who specializes in refrigeration:

This being said:
The 8045 is for 'Electric Heat Defrosting'
The 8145 is for 'Hot Gas Defrosting'

I posted the manual:
http://waterheatertimer.org/pdf/8000-series-defrost-sell-sheet.pdf

I also posted the 8145 and 8045 wiring side by side:
http://waterheatertimer.org/Paragon-timers-and-manuals.html#8045

The wiring changeover looks like the following:
Hot1 on 8045 is connected to terminal N => move this wire to terminal 1 on 8145
There is a jumper plate on 8045 that connects terminals 1 N 2
Jumper plate on 8145 connects terminals 1 and 2
If jumper plate is missing on 8145, use jumper wire to connects terminals 1 and 2
Hot2 on 8045 is connected to terminal X => move this wire to terminal N on 8145
Other wires on 8045 that are connected to terminal X => move to terminal N on 8145
Thermostat on 8045 is connected to NC terminal 4 => move this wire to NC terminal 4 on 8145
Heater on 8045 is connected to NO terminal 3 => move this wire to NO terminal 3 on 8145
Terminal X on 8145 is bare since this goes to cycling limit switch which is not used on 8045

The wiring diagrams appears below: