White-Rodgers  
   Installation and operating information for digital programmable thermostats.
   http://www.white-rodgers.com/

How Stuff Works  
   Detailed illustrations on how thermostats work, wiring, and components.
   http://www.howstuffworks.com/home-thermostat.htm

Homestore.com  
   Illustrated tutorial provides step-by-step instructions on installing a setback (programmable) thermostat.
   http://www.homestore.com/HomeGarden/HomeImprovement/HowTos/HowTos/CRHW_InstallingProgrammableThermostat.asp

Thermostats USA  
   Information on application, features and benefits, and troubleshooting.
   http://www.thermostatusa.com/Tech.asp

CornerHardware  
   Instructions for installing a programmable thermostat.
   http://www.cornerhardware.com/howto/ht018.html

Thermostats  
   Detailed fact sheet from U.S. Department of Energy. Covers automatic and programmable models. Description of types, operation and other considerations.
   http://www.eere.energy.gov/erec/factsheets/thermo.html

SSHC Inc  
   Astrostat installation and wiring instructions.
   http://www.sshcinc.com/TSSHC-1LV.htm

LUX Products  
   Troubleshooting chart.
   http://www.luxproducts.com/trouble_shoot/oper_tx9000_tx1500_tx1000_tx500.htm

On Q  
   Installation and wiring instructions for thermostat with remote monitoring capabilty.
   http://www.onqtech.com/pdf_lib/TechDocs/Installers_Manual/889157.pdf