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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.
Y594H1012
a
Wiring 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.
Y594H1012
a
Wiring 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.
Y594R1419
a
Wiring 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.
Y594R1243
a
Wiring 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
a
Both the thermostat and subbase must be replaced.