Specifications

Automation and Control Solutions
Honeywell International Inc.
1985 Douglas Drive North
Golden Valley, MN 55422
customer.honeywell.com
® U.S. Registered Trademark
© 2013 Honeywell International Inc.
33-00016—01 M.S. 10-13
Printed in United States
SPECIFICATIONS (CONTINUED)
Heat Indication:
Displays “Heat On” when the thermostat turns the heating on.
Auxiliary Heat Indication:
Displays “Aux Heat On” when the thermostat turns the auxiliary heat on.
Interstage Differential:
Comfort: The thermostat keeps the indoor temperature within 1 degree of the
setpoint (droop less control). The thermostat turns on stage 2 when the
capacity on stage 1 reaches 90%.
When the interstage differential is set to 1.0 or higher, the thermostat stages
the equipment based on how far the indoor temperature is from the setpoint.
Product Part Number Operating Ambient
Temperature
Operating
Relative
Humidity
Shipping
Temperature
Physical Dimensions in
in. (mm)
Color(s)
Thermostat TH8321R1001 32 to 120 °F
(0 to 48.9 °C)
5% to 90%
Non-Condensing
-20 to 120 °F
(-28.9 to 48.9 °C)
4-15/16 x 4-5/8 x 1-1/8
(126 x 118 x 29)
Arctic White
TH8320R1003 32 to 120 °F
(0 to 48.9 °C)
5% to 90%
Non-Condensing
-20 to 120 °F
(-28.9 to 48.9 °C)
4-15/16 x 4-5/8 x 1-1/8
(126 x 118 x 29)
Arctic White
TH8110R1008 32 to 120 °F
(0 to 48.9 °C)
5% to 90%
Non-Condensing
-20 to 120 °F
(-28.9 to 48.9 °C)
4-15/16 x 4-5/8 x 1-1/8
(126 x 118 x 29)
Arctic White
Equipment
Interface
Module
YTHM5421R1010
THM5421R1021
-40 to 165 °F
(-40 to 73.9 °C)
5% to 95%
Non-Condensing
-20 to 165 °F
(-28.9 to 73.9 °C)
9-11/32 x 4-53/64 x 1-19/32
(237 x 123 x 41)
Gray
Dimensions of thermostat in in. (mm).
M34521
4-15/16 (126)
4-5/8
(118)
1-1/8 (29)
3-5/16 (84)
Dimensions of Equipment Interface
Module in in. (mm).
M33331
4-53/64 (123)
8-7/8
(225)
9-11/32
(237)
1-19/32
(41)
Dimensions of VisionPRO cover
plate in in. (mm).
M34258
25/32
(20)
6-5/32
(156)
1-1/2
(38)
5-3/4
(146)
Clock Accuracy:
1 minute per month at 77 °F (25 °C). ± 2 minutes per month over
the operating ambient temperature range.
Mounting Means:
Thermostat mounts directly on the wall in the living space using
mounting screws and anchors provided. Fits a horizontal 2 x 4
in. junction box. Use a cover plate and its mounting bracket to
mount the thermostat onto a vertical 2 x 4 in. junction box.
Equipment Interface Module (EIM) mounts on HVAC equipment
or on a wall in the equipment room.