HVAC Thermostat

Deserie

I have an OLD thermostat. 8 terminals. 6 wires. Here's the problem.

When I popped the front, 4 of the wires were attached for sure: Y=Yellow, R-Red, G=Green, Blue=COM.

The other two wires are Orange and White.

Around the terminal that reads W2, there was a piece of wire, as if a wire (either the Orange or the White) had been attached, but broke off.

The three other terminals are E/W3, O, and B. From what I can tell they were not used.

Now I am trying to install a Honeywell RTH3100C. The terminals are: E, Aux, Y, G, O, L, R, B, C.

I am not certain if the Blue wire goes to B because there is no corresponding COM terminal.

And I am not certain if the Orange and White wires are required. And if they are required, where to put them.

As an experiment, I attached the Blue wire to B, the Orange wire to O and turned the power on.

The unit working and is blowing cold air. BUT IT WON'T TURN OFF. I have to turn it off at the breakers.

Help!!!!

zootjeff

What kind of system do you have? Furnace? AC? Heat pump?

cascadehvac

id hook the blue to C and the white to aux. doubt the orangwe was used. whithout the white terminal hooked up you will not get any heat