RC-80 OmniLT problem

[elmerbug]

Folks,
I have a new OmniLT, firmware 3.0, with a new RC-80. They are not communicating. I assume I am being dense and missing something obvious. I've been methodical about diagnosis:

1) Checked wiring
2) Used different wire
3) Tried 2 new RC-80s
4) Tried 2 new OmniLTs
5) Put a digital multimeter on the thermostat output on the controller. I see 5-seconds of ~250mv followed by 55 seconds at ~14 mv every minute
6) Verified thermostat node ID (1)
7) Verified comm settings (1)
8) Verified settings for non-programmable

Can you help me see what I am missing?
TIA,
Don

 

[edselrt]

1. Verify that red and black wire from t'stat is shorted.
2. Yellow to + zone 16
3. Green to + output 8
4. Black to - output 8

 

[elmerbug]

Red and black are shorted. This is an LT, so T-stat connections are dedicated. Thanks for the response.

 

[elmerbug]

Any thoughts, folks? I am stumped here.