Honeywell Q674L User's Manual

Honeywell Thermostats User's Manual - Q674L.
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X-XX UL

INSTALLATION INSTRUCTIONS

®U.S. Registered Trademark
Copyright © 1997 Honeywell Inc.  •            •   All Rights Reserved

T874R Thermostats and Q674L Subbases

Installation Instructions for the Trained Service Technician.

APPLICATION

The T874R Thermostat and Q674L Subbase provide 24 to 30 Vac control of 2-stage heating and 1-stage cool-ing heat
pump systems with manual changeover. Q674L Subbase provides EM.HT.-HEAT-OFF-COOL system switching and
AUTO-ON fan switching. See Table 1 for specific T874R/Q674L combinations.

Table 1. Thermostat/Subbase Specifications.

Thermostat/

Subbase

Package

Thermostat/

Subbase

Model

Numbers

LED

Indication

Changeover

Comments

See
Fig.

Y594R1243

T874R1152/

Q674L1207

AUX.HT.,

EM. HT.

Manual Cool

TRADELINE®; adjustable stage 2
heat anticipation. Fixed anticipation
in stage 1. Auto fan in EM.HT.

6

Y594R1300

T874R1475/

Q674L1520

AUX.HT.,
EM. HT.a

Manual Heat

or Cool

TRADELINE®; fixed heat
anticipation. Auto fan in EM.HT.

7

Y594R1425

T874R1616/

Q674L1587

AUX.HT.,

EM. HT.,

CHECK

Manual Heat

or Cool

SUPER TRADELINE®; fixed heat
anticipation. Factory installed jumper
across W1 and Y1. Auto fan in
EM.HT.

8

Y594R1615

T874R1822/

Q674L1710

AUX.HT.,

EM. HT.,

CHECK

Manual Heat

or Cool

TRADELINE®; fixed heat
anticipation. Auto fan in EM.HT.

10

Y594R1664

T874R1871/

Q674L1736

EM. HT.

Manual Cool

TRADELINE®; exact replacement
for York model no. 2TH11702224.

9

Y594R1672

T874R1889/

Q674L1736

EM. HT.

Manual Cool

TRADELINE®; exact replacement
for York model nos. 2TH11702324
and 6TH11702224.

11

Y594R1698b

T874R1905/

Q674L1777

EM. HT.

Manual Cool

TRADELINE®; exact replacement
for York model nos. 2TH11702324
and 6TH11702224.  Includes
C815A1054 Outdoor Thermistor.

11

Y594R1706b

T874R1913/

Q674L1777

EM. HT.

Manual Cool

TRADELINE®; exact replacement
for York model no. 2TH11702224.

9

Y594R1763

T874R1954/

Q674L1827

AUX.HT.,
EM. HT.a

Manual Cool

Requires C815A Outdoor Thermister
for outdoor reset. Fixed stage 1 heat
anticipation. No heat anticipation in
stage 2 heat. Auto fan in EM.HT.
Replaces Y594R1136.

5

Y594R1797

T874R1988/

Q674L1868

AUX.HT.,

EM.HT.

Manual Heat

or Cool

TRADELINE®

12

a

EM.HT. LED also shows compressor malfunction.

b

Premier White® color.

69-0392-9

0.535454s