How can I find what model number I have - house was built in 1992? Checked wall plate but saw no model # is on the backside of the thermostat?

This may help:

Thermostats (http://www.chathambrass.com/Pages/ProductSpecs/04LineVoltage.htm)

Look at other in the home, see if you can one with a label?

Describe what you have.

2 wire?

4 wire?