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T874 MULTISTAGE THERMOSTATS AND Q674 SUBBASES
60-2485—8
74
C1207
78
Obsolete. Friedrich; System: OVERRIDE-AUTO-OFF;
used with T874P1014.
T8600D2028
(programmable)
Wiring differences (old=new):
L=R, W=O; W-Y jumper
required; night setback.
C1215
97
Obsolete. Friedrich part no. AQ5315; System:
OVERRIDE-AUTO-OFF; OVERRIDE and SERVICE
LEDs; used with T874P1022, P1030.
T8600D2028
(programmable)
Wiring differences (old=new):
L=R, W=O; W-Y jumper
required; night setback.
C1223
73
Obsolete. Friedrich part no. AQ5323; used on systems
requiring night setback contacts; used with
T874G1584.
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):
L=R, W=O; W-Y jumper
required; night setback.
C1249
164
Includes MALFUNCTION LED; used with T874H1062;
used in Y594H1012.
Y594H1012
a
C1256
73
Obsolete. Used with T874G1618.
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):
L=R, W=O; W-Y jumper
required; night setback.
C1264
165
Obsolete. Carrier part no. HH93AZ193; used with
T874L1018 (HH07AT178).
See OEM for
replacement.
C1280
181,
203
Obsolete. McQuay heat pump; part no. 60687401;
COMP FAULT LED; used with T874K1019, L1034.
T8600D2028
See thermostat description for
replacement information.
C1298
76,
225
Obsolete. McQuay part no. 60684801; SERVICE LED;
used with T874A1523, A1549, D1918.
See OEM for
replacement.
C1306
75
Obsolete. McQuay part no. 60685001; SERVICE LED;
spring return momentary system switch position; used
with T874A1325.
See OEM for
replacement.
C1314
72
Obsolete. Trane part no. BAS-0429; used with T874A-F.
Q674C1058
C1322
173
Obsolete. Carrier part no. HH93AZ199; FAULT and CK
FILTER LEDs; used with T874H1070 (HH07AT166),
T874H1088 (HH07AT167) or T874H1153
(HH07AT167); used in Y594H1053.
Y594H1012
a
Wiring differences (old=new):
2=X.
C1330
177
Obsolete. LSI-Mammoth part no. 71115201; RESET
LED; used on systems with night setback contacts;
used with T874G1659, H1096; used in Y594G1427,
H1020.
Y594H1012
a
Wiring differences (old=new):
R1=R; R2=L.
C1355
74
Friedrich part no. AQ355; SERVICE LED; used with
T874H1112.
Y594H1012
a
Wiring differences (old=new):
Y1=O, Y2=Y; L-R jumper
required.
C1363
99
Obsolete. McQuay part no. 61202601; SERVICE LED;
auto fan in heat and cool mode; used with T874C.
T874C1125/
Q674B1075
a
Replacement has HEAT-OFF-
COOL.
219
Obsolete. Used with T874C.
See OEM for
replacement.
220
Obsolete. Used with T874W.
See OEM for
replacement.
100
Obsolete. Used with T874W.
T8611M2025
(programmable)
Includes night setback.
C1371
72
American Standard part no. ASYSTAT616.
Q674C1058
Table 9. Q674 Subbase Cross Reference.
Model
Number
Fig.
No.
Description
Q674 Trade
Replacement
Remarks
a
Both the thermostat and subbase must be replaced.