Reznor have released a MKIII wiring to some heaters which now employs a Live Lock Out Reset.
This LOR operates a relay inside the unit to bring the heater out of lockout.
Make 100% sure that the appliance you are working on employs the new wiring. Generally, linking the lockout reset terminal to Live will short circuit the control box and destroy it. You have been warned!
The following wiring diagram is an update to show the Heatmiser IQ+ Wiring with Live lockout reset.