Honeywell CT3550 Owner's Manual - Page 9

Table 2. Terminal Designations on Old and New Thermostats Terminal on Old Thermostat Connect To Description R, RHa, 4, V R Power Rc, Ra Rc Power for cooling W, W1, H W Heat Y, Y1, M Y Cooling G, F G Fan O O Changeover in cool. (Single stage heat pump only). Bb Bb Changeover in heat. (Single stage heat pump only). Cc, Xc, Bb Do not connect. Transformer common W2, H2 Y2 Do not continue installation. Second stage heat. Call 1-800-468-1502. Second stage cool. a If both RH and R terminals are present on existing thermostat, remove jumper and connect Rh to R and R to Rc. b Do not connect both O and B when wiring to a single stage heat pump. Connect O to O. Tape off B. c Tape off end of the wire with electrical tape and push the taped wire back into the wiring hole in the wall. STEP 5. INSTALL THE BATTERIES IMPORTANT Three AA alkaline batteries are included with the thermostat. Batteries must be installed for programming and operation of the thermostat and the heating/cooling system. ❑ Install the batteries in the wallplate so the positive terminals all point up (see illustration). WALLPLATE B R RC O W Y G INSTALL 3 AA ALKALINE BATTERIES AS SHOWN, POSITIVE (+) TERMINALS TOWARD TOP. M10622 9 69-1284-2