Without looking at the terminal block I cant be sure but i am almost certain like the others have said that is an ESI. Payne uses triple digit numbers on their terminal blocks and different style relays with their Omron PLC controller. Also, like ESI, Payne has a fully relay based hydro controller they installed before the PLC. I maintain a few accounts that still have them. I'm surprised you are having problems, I have this exact controller on my route and it runs like a clock.