Honeywell EASY-TO-SEE TRADELINE T841A Installation Instructions

TRADELINE®
APPLICATION
The T841A, B Easy-to-See™ Heat Pump Thermostat
provides 24 Vac control of 2-stage heating and 1-stage
cooling in heat pump systems, using manual change-
over.
The T841A Thermostat provides EM. HT.-HEAT-OFF-
COOL System switching and AUTO-ON Fan switching.
The T841B Thermostat provides HEAT-OFF-COOL
System switching and AUTO-ON Fan switching.
The side of the thermostat features raised numbers for
easy temperature setting by touch or sight. An audible
click is heard with indents every two degrees as the
temperature setpoint lever is moved. The thermostat
wallplate features raised letters to aid in setting System
switch and Fan switch settings. See Fig. 1.
The T841A,B includes a thermostat and wallplate.
Test holes are provided on the front of the thermostat to
accommodate test meter probes without removing the
thermostat from the wall. Remove the cover of the
thermostat to expose the test holes that are labeled to
correspond with the terminals on the thermostat back.
OPERATION
The stages of heat make sequentially as the temperature
drops. Make refers to the mercury switch initiating a call
for heat or cool.
There is about 1°F (0.6°C) between stages so the
second stage (auxiliary heat) makes only when the first
stage cannot handle the load. This °F is the interstage
differential.
For T841A Thermostat only (not for T841B Thermostat):
light emitting diode (LED) indicators light when
something specific happens within the system:
When AUX. HT. green or amber LED lights, auxiliary
heat (second stage heat) is operating because the
weather is so cold, the heat pump alone cannot
handle the load.
When red EM. HT. LED lights, emergency heat is
operating (electric strip heaters), because home-
owner physically switched to EM. HT. position. See
heating/cooling manufacturer instructions.
® U.S. Registered Trademark
Copyright © 2003 Honeywell International Inc. •
T841A,B Easy-To-See™
Heat Pump Thermostat
MERCURY NOTICE
This control contains mercury in a sealed tube.
Do not place the control in the trash at the end of
its useful life. If this control is replacing a control
that contains mercury in a sealed tube, do not
place your old control in the trash.
Contract your local waste management authority
for instructions regarding recycling and the
proper disposal of this control, or of an old control
containing mercury in a sealed tube.
INSTALLATION
When Installing this Product...
1. Read these instructions carefully. Failure to follow
them could damage the product or cause a hazard-
ous condition.
2. Check the ratings given in the instructions and on
the product to make sure the product is suitable for
your application.
3. Installer must be a trained, experienced technician.
4. After installation is complete, check out product
operation as provided in these instructions.
CAUTION
Electrical Hazard.
Can cause Disconnect electrical shock or
equipment damage.
Disconnect power before beginning installation.
IMPORTANT
— To prevent interference with the thermostat link-
age, keep wire length to a minimum and run
wires as close as possible to the thermostat
base.
— Do not short across coil terminals on the relay.
This can burn out thermostat heat anticipator.
— Never install more than one wire per terminal
unless a factory-supplied jumper with a spade
terminal is used.
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INSTALLATION INSTRUCTIONS
69-1043-2