When using hovabator with t-stat: leave wafer out?

Does the wafer need to be installed or should I just leave it out when using a t-stat with it?

Thanks

I instslled the wafer and turned the screw in there as far as it would go. I hooked the hovabator to my herpstat pro and the temps have been sitting steady between 89-5 and 90.2. I dont think the hovabator will function with the wafer out? Im not 100 percent sure on that but this is what I did and so far it works perfect. Been set up for 2 weeks. Hope this helps you out

Just leave the wafer thermostat wide open at maximum heat and plug it into your external thermostat.