Specifications

System Start and Test

1. Plug all thermostats into sub-bases. Turn GEN II power switch (E) to ON.

2. Choose any Thermostat and change its address from 25 to 1.

(See ModStat installation instructions – Configuration – Addressing).

3. Turn GEN II power switch OFF and then ON. The Display should flash 01 and then show the

leaving air temperature. This confirms your successful wiring and communication with that

thermostat.

4. If 01 is displayed, change the next thermostat’s address from 25 to 2. Turn the GEN II power

switch OFF and then ON. The display should flash 02 and then show the temperature. Re-

address thermostats one at a time.

5. After each stat is re-addressed, turn the power switch off and then on. This will verify that the

re-addressed stat has been found by the GEN II Controller.

This procedure will simplify your installation and will confirm your wiring is correct and that the GEN

II controller can communicate over the 2-wire twisted pair data link with every thermostat in your

system.

Troubleshooting

When stat #1 is not found:

1. Check remaining stats to verify that all addresses are 25.

2. Check all R & C wiring for proper color-to-color connections. Even if the stats lighted, all R

wires at the thermostat must be connected to the GEN II R terminal. All C wires must be

connected to the GEN II C terminal. Confirm the daisy chain wiring is correct at this time.

3. Check RX & TX wires for proper color code and connections; polarity is imperative. All RX

connections must land on RX terminal on the following thermostat, and all TX connections must

connect to TX terminal on each thermostat.

4. Check R & C wires for opens or shorts.

Checking the Daisy Chain for opens or shorts:

Start from the GEN II board, and follow RX & TX wires to the first sub-base. Remove the RX & TX

wires going to the next sub-base in the link. Plug a stat into the first sub-base, and address it as #1.

Turn the GEN II power switch off, then on, to see if the display flashes.

1. If 01 is displayed, the first link of the daisy chain is OK. Reconnect the wires going to sub-

base.

2. Repeat these steps with a stat numbered 02. If the number 02 is displayed, then

Communication is confirmed.

When the correct number does not appear for a link, that link is either shorted or open. A link of the

daisy chain, which is open or shorted, must be repaired before the next thermostat is checked.

When the thermostats are correctly addressed, wired and linked, the total number of stats on your

job connected to the GEN II Control board will be displayed when the board is turned on.

After the correct number of connected thermostats is displayed, complete the wiring of AC unit or

heat pump connections; then make heat and cool calls to the GEN II Controller.