T874 MULTISTAGE THERMOSTATS AND Q674 SUBBASES
73 60-2485—8
B1554 82 Obsolete. TRADELINE; includes LOCKOUT LED and
removable jumpers between RC and RH terminals;
used with T874C1877; used in Y594C1421.
Y594D1347 Jumper RH-RC; system
switch: Off-HEAT-AUTO-
COOL.
B1562 45 Obsolete. Amana logo; part no. P1217701F;
removable jumpers between RC and RH terminals.
Q674B1034
B1570 45 Obsolete. Armstrong logo; part no. 03299A18. Q674B1034 Replacement is beige.
B1588 45 Obsolete. Standard OEM. Q674B1034 Replacement is beige.
Q674C System: OFF-AUTO; Fan: AUTO-ON
C1009 72 Standard OEM; used with T874D1082; used in
Y594D1024.
Q674C1058
C1017 Obsolete. Includes factory-installed RC-RH jumper;
used with T874A,F,Q.
Q674C1058
C1033 72 Trane part no. BAY28X187. Q674C1058
C1041 74 Obsolete. Command Aire heat pump; used with
T874H1005, H1054.
Y594H1012aWiring differences (old=new):
Y1=O, Y2=Y; W-Y jumper
required.
C1058 72 TRADELINE Q674C1058
C1066 73 Obsolete. Command Aire heat pump; used with
T874G1352.
Y594H1012aWiring differences (old=new):
Y1=O, Y2=Y, L=R, R=none; R-
L jumper required; no night
setback.
T8600D2028
(programmable)
Wiring differences (old=new):
Y1=O, Y2=Y, L=R; W-Y
jumper required; night
setback.
C1074 81 Obsolete. Used with T874C1018. Q674C1058 Jumper W2-Y1 and RH-RC.
C1090 77 Obsolete. LSI-Mammoth heat pump; used with
T874K1001.
Y594R1419aWiring differences (old=new):
RH-RC=R, W1=B, W3=W2,
W2=W1; remove Y1-W1
jumper.
C1108 143 Obsolete. Northrup special; AUX HEAT LED; used with
T874G1139.
Y594R1243aWiring differences (old=new):
Y1=Y, W1=W2, C=X.
C1116 76 Obsolete. McQuay part no. 02005959; two LEDs; used
with T874D1116.
Q674C1058 Replacement has no LEDs.
C1124 79 Obsolete. LSI-Mammoth heat pump; RESET LED;
used with T874G-H; used in Y594G-H.
Y594G1294
T8600D2028
C1132 75 Obsolete. McQuay part no. 03005049; spring return
momentary system switch position; used with
T874A1283.
See OEM for
replacement.
C1140 78 Obsolete. McQuay no. 860-442728B-00; System:
OVERRIDE-AUTO-OFF; used with T874P1006.
T8600D2028
(programmable)
Wiring differences (old=new):
L=R, W=O; W-Y jumper
required; night setback.
C1157 72 Obsolete. York part no. 2TB04700124A. Q674C1058
C1165 192 Obsolete. McQuay part no. 03005050; spring return
momentary system switch position.
See OEM for
replacement.
C1173 96 Obsolete. American Air Filter part no. 4ELN-8787; used
with T874C1133.
Q674C1058 Replacement has no LEDs.
C1181 76 Obsolete. California heat pump; used with T874C1000. Q674C1058
C1199 163 Obsolete. American Air Filter part no. 4ELN-8788; two
LEDs; spring return momentary system switch position;
used with T874G1485, G1535.
T8600D2028 No momentary reset switch.
Table 9. Q674 Subbase Cross Reference.
Model
Number
Fig.
No. Description
Q674 Trade
Replacement Remarks
aBoth the thermostat and subbase must be replaced.