Well, it seems that the twin relay board that I got is not compatible with the G540. The relay board needs a high signal to trigger, from what I have gathered on the Gecko forum, the G540 will not provide that. So, I guess I'll be getting a panel mount relay and hope that I can return the twin relay board. I'm going with the 12V variety instead of 48V, since that involves less rewiring (current relay board is getting 12V from the Gecko chiller unit) and most every place is out of stock on the 48V relays.