Hooking Up Nest to Radiant System

Anyone here know about hooking up a Nest radiant system.

I have a two wire, three zone radiant heat system. I am trying to connect it to a Nest thermostat. Since it is a two wire system, I am using the Nest Power Connector. Right now I only have a single Nest.

The valves are Honeywell v8043e.

I have been able to get power to the Nest, but it won't send a call for heat. The other thermostats work, but the Nest will only get power. Any ideas about what I may be doing wrong?

Current wiring.

Original Wiring. The green wrapped cable goes to the transformer.

With the Power Connector. This powers the Nest, but won't trigger the heat.

Honeywell AT72D1683 Transformer

The furnace board.