Maybe I'm missing this, but you need to have everything together, turn it on, and check one heater, in this case term inals 5 & 6 -
Put the VOM (but really a "wiggy" would be my choice) across the leads 5 and 6 only, not at all to ground. Any reading other than 230v (approx) means the circuit is not being completed. This is the 1st place to start. I can walk you through the rest after you do this and tell me how much, if any, voltage you have.
PROVISOS - THIS INFORMATION IS MEANT FOR INFORMATIONAL PURPOSES ONLY. I STRONGLY RECOMMEND THAT A LICENSED ELECTRICIAN PERFORM THIS WORK. I CAN NOT GUARANTEE THAT THE INFORMATION I HAVE GIVEN YOU IS ACCURATE FOR YOUR SPECIFIC APPLICATION, NOR DO I ACCEPT RESPONSIBILITY FOR FAILURE, CATASTROPHIC OR OTHERWISE.