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View Full Version : How do I change from standard Lennox 21J7201 to a compatible digital model?


ray0073
Apr 5, 2009, 06:52 PM
I have a standard rectancular wall mounted electric Lennox 21J7201 (house is 10 years old) and want to change to digital model that has 5 / 2 programming (a 5-day and a weekend program). I have an air handler unit in the garage that controls the central air / heat unit outside. The air handler in the garage comes on , but the unit outside (AC) comes on for a while then off. Was told the (mercury) thermostat may be bad - turning it down to lowest setting does not cause the outside AC to come on.

Specs for the Lennox are: 6 wires (Red, Y1 Yellow, Green, Orange, Blue, White) black and brown wires present but not hooked up to anything. There is an E terminal but no wire goes to it. The sub-plate number is 3AAT89B38E1... says 30VAC / 1.5A / Class 2 thermostat. Any mid priced units ($50 - $80) where the wires would be compatible and easy for a novice to install? Thanks for any assistance.

Ray

Joshdta
Apr 5, 2009, 06:57 PM
Lowe's should have a honeywell product that you are looking for fairly cheep. Are you sure it is the t-sta and not a problem with the outdoor unit? Is the fun inside running?