Q674 Subbase Cross Reference - Honeywell T874 Product Data

Model Fig.
Number No.
Q674A System: HEAT-AUTO-COOL; Fan: AUTO-ON
A1001 71 Standard OEM.
A1019 71 TRADELINE® model; used with T874A-D.
A1035 71 Obsolete. Trane part no. BAS-0435; used with T874A-D.
A1043 71 Honeywell logo; TRADELINE model;
A1050 71 Obsolete. Standard OEM.
Q674B System: HEAT-OFF-COOL; Fan: AUTO-ON
B1000 45 Standard OEM; used with T874C1570, C1695, C1703,
D1843; used in Y594C1363.
B1018 44 Standard OEM; used with T874B1035, D1082; used in
Y594B1026, D1016.
B1026 45 Obsolete. System: HEAT-OFF-RESET-COOL.
B1034 45 TRADELINE
B1042 47 Obsolete. Used with T874R1004, R1509; used in
Y594R1029, R1334.
B1059 45 Obsolete. Factory installed RC-RH jumper; used with
T874C1059; used in Y594C1256.
B1075 46 Auto fan in heating and cooling mode; used with
T874B1035, C1000, D1082; used in Y594D1040.
B1083 51 Obsolete. Carrier part no. HH93AZ178; factory
installed RC-RH jumper.
B1091 45 Obsolete. Carrier part no. HH93AZ184; factory
installed RC-RH jumper.
B1109 47 Obsolete. Addison heat pump; used with T874R1012.
B1117 44 Obsolete. Carrier part no. HH93AZ180; factory
installed RC-RH jumper.
B1125 53 Obsolete. York part no. 2TB04700324A; used with
T874D1041.
B1133 48 Obsolete. Includes FILTER LED; used with
T874D1082; used in Y594D1156.
B1141 51 Trane part no. BAY28X185; automatic fan operation in
heat and cool mode.
B1158 50 Obsolete. Used with T874G1071.
B1166 249 Carrier part no. HH93AZ179; factory installed RC-RH
jumper; LOCKOUT LED; used with T874C1075
(HH07AT170).
B1190 52 Obsolete. Wards special; factory installed RH-RC and
F-W3 jumpers; used with T874C1372.
B1208 187 Obsolete. Used with T874C1422.
B1216 54 Used with T874W1015 and C815A1005; used in
Y594W1014.
B1224 49 Obsolete. Lennox part no. 25F7301; four LEDs; used
with T874C1430.
a Both the thermostat and subbase must be replaced.
T874 MULTISTAGE THERMOSTATS AND Q674 SUBBASES
Table 9. Q674 Subbase Cross Reference.
Description
71
Q674 Trade
Replacement
Q674A1019
Q674A1019
Q674A1019
Q674A1019
Q674A1043
Q674B1034
Q674B1018
Q674B1034
Q674B1034
Wiring differences (old=new):
Y594R1243 a
W1=W2.
Q674B1034 Field wire RC-RH.
Q674B1075
One system transformer only.
Q674B1075
a
Q674B1034
Wiring differences (old=new):
Y594R1243
a
W1=W2.
Q674B1018 a
Jumper RC-RH; replacement
Q674B1075
a
has no LOCKOUT LED.
Q674B1018
Q674B1075 Set T874 H1 anticipator for
combined load of heat relay
and fan relay.
T874C1018/ W1-Y1 and RH-RC jumpers
required.
Q674B1018 a
Y594C1421 or Replacement only requires
one transformer and has no
Q674B1075
a
LOCKOUT LED.
Gas Furnace:
Q674B1034
Electric Furnace:
Q674B1075
None
Q674B1216
Q674B1034 Replacement has no LEDs.
Remarks
60-2485—8