Honeywell T874/Q674 Multistage Thermostat

T874 THERMOSTATS

Model Number System Stages Anticipator Ranges Remarks

Heating (Adjustable) Cooling (Fixed)

Heat Cool Other Stage 1 Stage 2 Stage 1 Stage 2

T874A1150 1 1 - 0.1 to 1.2 - 0 to 1.5 - Includes locking cover with thermometer and field-adjustable range stops and field-adjustable locking levers.

T874D1165 2 2 - 0.1 to 1.2 0 to 1.2 0 to 1.0 Includes locking cover with thermometer and field-adjustable range stops and field-adjustable locking levers.

T874 THERMOSTATS
Model Number	System Stages	Anticipator Ranges	Remarks
Heating (Adjustable)	Cooling (Fixed)
Heat	Cool	Other	Stage 1	Stage 2	Stage 1	Stage 2
T874A1150	1	1	-	0.1 to 1.2	-	0 to 1.5	-	Includes locking cover with thermometer and field-adjustable range stops and field-adjustable locking levers.
T874D1165	2	2	-	0.1 to 1.2	0 to 1.2	0 to 1.0	Includes locking cover with thermometer and field-adjustable range stops and field-adjustable locking levers.

Q674 SUBBASES

Model Number Switch Positions LED Indication Use With Terminal Designations Remarks

System Fan

Q674A1019 HEAT-AUTO-COOL AUTO-ON - T874A-D Rh, Rc, Y1, Y2, W1, W2, G -

Q674B1018 HEAT-OFF-COOL AUTO-ON - T874A-D Rh, Rc, Y1, Y2, W1, W2, G, O, B -

Q674 SUBBASES
Model Number	Switch Positions	LED Indication	Use With	Terminal Designations	Remarks
System	Fan
Q674A1019	HEAT-AUTO-COOL	AUTO-ON	-	T874A-D	Rh, Rc, Y1, Y2, W1, W2, G	-
Q674B1018	HEAT-OFF-COOL	AUTO-ON	-	T874A-D	Rh, Rc, Y1, Y2, W1, W2, G, O, B	-

Y594 COMBO PACKS - For Heat Pump and Other Applications

Model Number Contains Thermostat/Subbase LED Indication Changeover Heat Anticipation Terminal Designations System Switch Auto Fan in Emergency Heat Color Remarks

Y594C1322 T874C1638/Q674L1561 AUX.HT., EM. HT. Manual Cool
Stages 1 and 2

0 to 1.0A Fixed
R1, Y1, W2, G, O, B, E, L, X
EM.HT

HEAT-OFF-COOL
Yes Beige with Brushed Gold Faceplate For Heat Pump applications. DoD. Includes locking cover with thermometer, and non-adjustable range stops set at 72F max. heat and 78F min. cool.

Y594C1389 T874C1810/Q674C1488 HI, LOW -
Stage 1 - 0 to 1.2A, adj.

Stage 2 - 0 to 1.5A, fixed
R, G, W1, W2, Y, B HEAT-OFF-COOL N/A White with Gray Subbase For two-stage gas valves, one stage cooling non-heat pump applications.

Y594D1354 T874D2031 (does not include cover) Q674E1049 and TG504A1025 Key Lock Cover None - Stages 1 and 2 - 0.1 to 1.2A Rh, W1, W2, O, B, G, Y2, Y1, Rc
OFF

HEAT-AUTO-COOL
N/A Beige with Brushed Gold Faceplate For conventional multistage heating-cooling applications.

Y594G1419 T874G1741/Q674F1444
AUX.HT., EM.HT. CHECK
Auto, Cool or Heat
Stage 1 and 2 - 0 to 1.0A Fixed
R, Y1, W1. W2, W3, G, O, B, E, X, X1, X2
OFF

EM.HT.

HEAT-AUTO-COOL
Yes Beige with Brushed Gold Faceplate
For Heat Pump Applications. Includes locking cover with thermometer, field-adjustable range stops and field-adjustable locking levers

Y594G1476 T874G1741/Q674F1477 White

Y594R1243 T874R1152/Q674L1207 AUX.HT., EM.HT. Manual Cool
Stage 1 - 0 to 1.0 Fixed

Stage 2 - 0.1 to 1.2A Adjustable
R1, Y1, W2, W3, G, O, B, E, L, X
EM.HT.

HEAT-OFF-COOL
Yes
Beige with Brushed Gold Faceplate For Heat Pump Applications

Y594R1300 T874R1475/Q674L1520 AUX.HT., EM.HT. Manual Cool Stages 1 and 2 - 0 to 1.0A Fixed R, Y, W2, G, O, B, E
EM.HT.

HEAT-OFF-COOL
Yes

Y594R1425 T874R1616/Q674L1587 AUX.HT., EM.HT. CHECK Manual Cool or Heat Stages 1 and 2 - 0 to 1.0A Fixed R, Y, W1, W2, W3, G, O, B, E, L, X1, X2
EM.HT.

HEAT-OFF-COOL
Yes For Heat Pump Applications. Includes locking cover with thermometer. Field-adjustable range stops and field-adjustable locking levers. Removable jumper between W and Y.

Y594 COMBO PACKS - For Heat Pump and Other Applications
Model Number	Contains Thermostat/Subbase	LED Indication	Changeover	Heat Anticipation	Terminal Designations	System Switch	Auto Fan in Emergency Heat	Color	Remarks
Y594C1322	T874C1638/Q674L1561	AUX.HT., EM. HT.	Manual Cool	Stages 1 and 2 0 to 1.0A Fixed	R1, Y1, W2, G, O, B, E, L, X	EM.HT HEAT-OFF-COOL	Yes	Beige with Brushed Gold Faceplate	For Heat Pump applications. DoD. Includes locking cover with thermometer, and non-adjustable range stops set at 72F max. heat and 78F min. cool.
Y594C1389	T874C1810/Q674C1488	HI, LOW	-	Stage 1 - 0 to 1.2A, adj. Stage 2 - 0 to 1.5A, fixed	R, G, W1, W2, Y, B	HEAT-OFF-COOL	N/A	White with Gray Subbase	For two-stage gas valves, one stage cooling non-heat pump applications.
Y594D1354	T874D2031 (does not include cover) Q674E1049 and TG504A1025 Key Lock Cover	None	-	Stages 1 and 2 - 0.1 to 1.2A	Rh, W1, W2, O, B, G, Y2, Y1, Rc	OFF HEAT-AUTO-COOL	N/A	Beige with Brushed Gold Faceplate	For conventional multistage heating-cooling applications.
Y594G1419	T874G1741/Q674F1444	AUX.HT., EM.HT. CHECK	Auto, Cool or Heat	Stage 1 and 2 - 0 to 1.0A Fixed	R, Y1, W1. W2, W3, G, O, B, E, X, X1, X2	OFF EM.HT. HEAT-AUTO-COOL	Yes	Beige with Brushed Gold Faceplate	For Heat Pump Applications. Includes locking cover with thermometer, field-adjustable range stops and field-adjustable locking levers
Y594G1476	T874G1741/Q674F1477	White
Y594R1243	T874R1152/Q674L1207	AUX.HT., EM.HT.	Manual Cool	Stage 1 - 0 to 1.0 Fixed Stage 2 - 0.1 to 1.2A Adjustable	R1, Y1, W2, W3, G, O, B, E, L, X	EM.HT. HEAT-OFF-COOL	Yes	Beige with Brushed Gold Faceplate	For Heat Pump Applications
Y594R1300	T874R1475/Q674L1520	AUX.HT., EM.HT.	Manual Cool	Stages 1 and 2 - 0 to 1.0A Fixed	R, Y, W2, G, O, B, E	EM.HT. HEAT-OFF-COOL	Yes
Y594R1425	T874R1616/Q674L1587	AUX.HT., EM.HT. CHECK	Manual Cool or Heat	Stages 1 and 2 - 0 to 1.0A Fixed	R, Y, W1, W2, W3, G, O, B, E, L, X1, X2	EM.HT. HEAT-OFF-COOL	Yes	For Heat Pump Applications. Includes locking cover with thermometer. Field-adjustable range stops and field-adjustable locking levers. Removable jumper between W and Y.

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