can you measure from blue to white in both cases (above and below set temp)

And what does the label say on the contactors? Kind of strange all three would go at once, I'm trying to see if they are getting trigger voltage.

I think we said each element draws less than 20 amps, so 12 gauge is ok. The total was close to 60, needing heavier service wire. The covering may be for temperature?

I hate to re-invent the wheel, but is it time to modernize? one of these, with additional SSR (1 per element): https://smile.amazon.com/Inkbird-Temperature-Thermostat-Controllers-Fahrenheit/dp/B01KNXETWS/ref=sr_1_3?ie=UTF8&qid=1489526227&sr=8-3&keywords=pid+temp+controller

I'll measure them tonight. They were 8 or 10V IIRC.

So that controller will replace mine and the SSRs would replace the contactors?

I'm all for that given the price.

Here's the controller I'm using now.

https://www.amazon.com/Precision-Digital-Trident-Temperature-PD765-6R3-20/dp/B01NBMQ3TA/ref=sr_1_6?s=kitchen&ie=UTF8&qid=1489526589&sr=8-6&keywords=precision+digital+trident

I assumed your controller was older/mechanical. No need to change controller. If Mercury relays are bad, your controller outputs 24 volts, could drive a SSR(s) like this: https://www.amazon.com/Inkbird-Solid-State-Relay-SSR-40DA/dp/B01MCWO35P/ref=sr_1_4?s=industrial&ie=UTF8&qid=1489526980&sr= 1-4&keywords=ssr

I don't think mine has the 24V out. I'll call the company tomorrow, they are local and closed because of the snow.

I don't know anything about mercury contactors. I wonder if they need a load to function?

Spec sheet here. It might not be 24v. sorry.
https://www.predig.com/pd765

0V above and below temp between white and blue on the contactors.

White is T2/common. Blue goes to the controller relay. When I check blue against T1 or T3 (black & red), I get 120V.

So I think it's the controller.

I'll call them tomorrow. Too frustrating.

Here's the basic wiring diagram for the circuit. Very simple.

http://forums.pelicanparts.com/uploa...1489541722.jpg

OK, I've fixed it. Works perfectly now. But some interesting details.

It sends 211V to each heating element. Any suggestions on wiring I should use? With that, I can actually do a proper test run.

When the relay clicks off at 210F, the volt values go back to the 40-50-60 as above.

If it's 20A or under, 12 gauge should be ok.