I did some more testing this morning and it may come down to a bad relay. there's a high capacity switching relay on the temperature controller board that, I believe, used to click (something did) when turning the temp higher. makes a lot of sense. When I pulled the relay, the base was wet and I'm guessing the capacitor gave up the ghost.
Before finding that, here's what I did.
There are three heating elements, I labeled I, II and II. The 2 leads going to each one were already labeled 1 and 2, 3 and 4, 5 and 6, respectively to I, II and III.
With the leads NOT CONNECTED, POWER ON:
I have continuity between the two terminals in each heater
For heater I, 120V connecting 1 and 2
N or G and 1: 46V
N or G and 2: 120V
For heater II, 75V connecting 3 and 4
N or G and 3: 10V
N or G and 4: 120V
For heater III, 79V connecting 5 and 6
N or G and 5: 13V
N or G and 6: 120V
With the leads CONNECTED, POWER ON:
For heater I, 0V connecting 1 and 2
G and 1: 120V
G and 2: 120V
For heater II, 0V connecting 3 and 4
G and 3: 120V
G and 4: 120V
For heater III, 0V connecting 5 and 6
G and 5: 120V
G and 6: 120V
Here's how the single phase install goes. There are 3 terminals and a ground
T1 is hot, T2 is neutral, T3 is hot, ground is ground.
T1-T2 and T2-T3 is 115V between each. T1-T3 is 230V.
The basic e- flow is:
T1 to a Mercury Contactor (each of the 3 black elements on the left of the control box)
Temperature controller to Mercury Contactor
MC to terminal strip
Terminal strip to heating element
T3 to terminal strip and then to heating element
Only wiring diagram I have
macro view
Terminals
Controller face
Controller wiring. note 1, 2 and 3 are mercury contactors. Circuit board closest to the center is the temp controller board. note that the black rectangle is the receptor for the relay.
Board close-up. The 3 wires, red, green and black w/ spade connectors at the lower left go to the dial on the controller face. The braided wire goes to a probe that is inserted in heating element I.
Wide angle of controller
