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Thermostat Wiring

Name: Pete  City: Philly

Question: I tried to install a programmable thermostat to change my regular thermostat, and now I can't get either to work. It's a 4 wire system, and I'm certain that I rewired it to the old spec. The fan won't turn on, nor heat/cold.

Name: WILLIAM | Date: November 20, 2005, 18:56
Answer: IS THE THERMOSTAT COMPATABLE WITH THE HVAC

Name: Tonnt | Date: May 28, 2006, 20:54
Answer: You blew a transformer that feeds it 24 volts. Always shut off the power to the furnace before changing t-stat. If red and common ever touch bang you need new t-stat. But i dont think thats possible with only 4 wires. You sure you dont have 5? Normal wiring red to r,yellow to y, green to g, White to w. Probally wired wrong you really can short out transformer on 4 wire t-stats