Another case of Nest not talking to boiler

[TheFrog]

I've read many threads and answers on the topic, but nothing worked for me. Here is some background, along with what I have tried:

We have radiant heat and I had turned the thermostats off for the summer (since we don't have AC). When I tried to turn them on last night, the boiler did not trigger. You can hear a click at the boiler, but it doesn't start. Note that we have another forced air section w/o a next thermostat and it's working fine.

What I tried, in order with the thermostats:

1) Factory reset. No change.

2) Charged the thermostats over night. No change.

3) Soft-reset the thermostat

4) Modified the safety temp up and down I had read there was a software bug. No change.

Any suggestion is appreciated as I am running out of hair to pull...

[Todbone]

If it's just a boiler connected to the Nest, I assume there are just two wires connected to it? If so, they should be connected to R (or Rh) and W1 (or W). Is this the case?

[TheFrog]

Thanks for your response. Yes, this is the case and that has not changed since last winter when everything worked happily...

[Todbone]

The problem most likely is going to be with the boiler itself. If you hear a click at the boiler and țhen nothing happens, it sounds like an ignition problem. 

[TheFrog]

Possibly, but the same boiler is firing just fine when I'm turning on the heat in a different part of the house that is controlled by a non-nest thermostat, so it seems to me like the nest thermostats are somehow the issue as this is the only variable between the 2 zones...