Honeywell T874 - Page 72

T874 MULTISTAGE THERMOSTATS AND Q674 SUBBASES
60-2485—8 72
B1240 234 Obsolete. Northrup heat pump; AUX HEAT LED; used
with T874G1139.
Y594G1252
a
Wiring differences (old=new):
Y1=Y2, W1=W2; EM HT
system switch position is not
operational.
B1257 56 Obsolete
. LSI-Mammoth; RESET LED; automatic fan
operation in heat and cool modes; used with
T874C1471; used in Y594C1314.
Q674B1075 Replacement has no LED.
B1273 57 Obsolete. McQuay part no. 860-442727B-00; System:
OVERRIDE-HEAT-OFF-COOL; used with T874P1006.
T874A1036/
Q674B1075
a
Wiring differences (old=new):
Y=Y1, L=R, W=O; jumper Y1-
W1; no night setback.
T8600D2028
(programmable)
Wiring differences (old=new):
L=R, W=O; W-Y jumper
required; night setback.
B1281 191 Obsolete
. Carrier no. 42QH400103; System: HEAT-
OFF-COOL; Fan: LOW-HI-CONT; international
symbols on switches; used with T874R1319.
See OEM for
replacement.
B1299 46 Obsolete. Heil Quaker part no. HQ521714HW. Q674B1075
B1307 62 Obsolete
. Includes two LEDs; used with T874F1122. T874F1015/
Q674D1040
a
Replacement has no LEDs.
B1315 68 Obsolete
. Friedrich part no. AQ5215; OVERRIDE and
SERVICE LEDs; used with T874P1022, P1030.
T8600D2028
(programmable)
Wiring differences (old=new):
L=R, W=O; W-Y jumper
required; set dual fuel switch
to electric heat; night setback.
B1331 65 Obsolete
. Includes two LEDs; used with T874A1002. Q674B1034 Replacement has no LEDs.
B1349 67 Obsolete. Goettl part no. 372072; used with
T874R1541.
Y594R1300
a
B1356 138 Obsolete. Carrier part no. HH93AZ192; used with
T874L1018 (HH07AT178).
See OEM for
replacement.
B1372 44 Obsolete
. Trane part no. BAS-0427; used with T874A-D. Q674B1018
B1380 46 Obsolete
. Trane part no. BAS-0426; used with T874A-D. Q674B1075
B1398 48 Obsolete
. Trane part no. BAS-0431; FILTER LED; used
with T874A-D.
Q674B1034 Replacement has no LEDs.
B1406 172 Obsolete
. Carrier part no. HH93AZ200; FAULT and
CHECK FILTER LEDs; used with T874H1070
(HH07AT166), T874H1088 (HH07AT167) or
T874H1153 (HH07AT167); used in Y594H1046.
T874A1150/
Q674B1075
a
Wiring differences (old=new):
Y=Y1; jumper W1-Y1;
replacement has no LEDs.
B1414 51 American Standard (Trane) part no. ASYSTAT1617. Q674B1075
B1448 215 Obsolete
. Carrier part no. HH93A2202; Fan: Lo-Med-
High-On; used with T874L1059.
See OEM for
replacement.
B1455 214 Obsolete
. Carrier part no. HH93AZ208; Fan: Lo-Med-
High-On; used with T874A1424 (HH07AT194).
See OEM for
replacement.
B1463 45 Trol-A-Temp; used with T874D1801. None See Trol-A-Temp.
B1471 45 Trol-A-Temp; used with T874D1827. None See Trol-A-Temp.
B1513 53 Obsolete
. TRADELINE; exact replacement for
Q674B1125 (York part no. 2TB04700324).
Q674B1075 Jumper RC-RH; replacement
has no LOCKOUT LED.
B1521 53 Obsolete
. Carrier Canada part no. HH93AZ179-W;
gray color; includes LOCKOUT LED and removable
jumpers between RC and RH terminals.
Q674B1075 Jumper RC-RH; replacement
has no LOCKOUT LED; beige
color.
B1539 45 Obsolete
. Carrier part no. HH93AZ139; used with
T874D2049; used in Y594D1370.
Q674B1034
B1547 237 Obsolete
. TRADELINE; gray color; used with
T874C1810; used in Y594C1389.
Y594C1389
Table 9. Q674 Subbase Cross Reference.
Model
Number
Fig.
No. Description
Q674 Trade
Replacement Remarks
a
Both the thermostat and subbase must be replaced.