stickyfinger
Well-Known Member
I just pulled up Kal's wiring diagram and compared it to the schematic on the octal relay he used and my initial diagram is essentially the same. His octal relay has the terminal numbers arranged differently.
Here's Kal's description: "The safe start interlock relay only receives power when the POWER KEY switch is set to ON and all three other switches are set to OFF. Once the interlock relay receives power and latches, it feeds into the POWER IN RELAY coil to turn on the rest of the control panel. Once latched, power for the interlock relay is then also drawn directly from the POWER KEY switch through one of the poles in the interlock relay that is now closed. This keeps the interlock relay coil energized and allows the other three switches to be turned ON or OFF as required without turning off the control panel while in use or affecting the interlock capability. If power to the panel is cut, the interlock relay releases and the three switches must be set to OFF before the panel may be powered on again."
So, I think the power from the key switch to terminal 5 is essentially what stays latched when the pump/element switches are turned off and on, keeping power going to the main contactor. It only becomes unlatched when the key switch is turned off. I think
I am just looking at this interlock relay and have never heard of one before (I'm new to control panels.) You want one of these interlock relays in the panel so that you can't provide power to the panel without the 2 pump and 2 heating element "on" switches being in the "off" or open position, right? Is this an added safety feature for the case when you have 1) "on" switches that are not illuminated OR 2) illuminated switches in which the light in the switch has burned out?