Honeywell T874 - page 74

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.
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):
L=R, W=O; W-Y jumper
required; night setback.
C1249 164 Includes MALFUNCTION LED; used with T874H1062;
used in Y594H1012.
Y594H1012a
C1256 73 Obsolete. Used with T874G1618. 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):
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.
Y594H1012aWiring 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.
Y594H1012aWiring differences (old=new):
R1=R; R2=L.
C1355 74 Fr iedrich part no. AQ355; SERVICE LED; used with
T874H1112.
Y594H1012aWiring 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/
Q674B1075a
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
aBoth the thermostat and subbase must be replaced.