I have purchased a Hayward H100 gas heater and I would like to hook it up to my spa pack. I did have an old Laars heater hooked up through a fireman's switch. When I look at the diagram from the H100 heater, it does not contain a fireman's switch. I know where to kook into my spa pack, because I am bypassing the elec hater that is in the spa pack.
Called Hayward T/S, and I have received 4 different answers.

Any advice? I do have some pictures of the wiring.