Originally Posted by ArrowHead
Any reason why Solid State Relays are recommended, versus a mechanical(?) relay? I had an electrical engineer tell me that SSRs can fail, and when they do it is often in the closed mode - which means an overheated element.
Any electrical whiz who can comment on this?
When a PID adjusts the power output it does so by cycling on and off at high frequency. Mechanical relays are not built to withstand that frequency of switching.
The electrical engineer is correct that SSRs can fail closed. Many will place a mechanical relay between the SSR and the heating element, operated by a switch on the control panel. When the switch is turned off you know you have no power to the element.
I am no electrical whiz, but that should sum it up.