Commercial
Thermostats
DESCRIPTION
Thermostats can provide either temperature control or over-
temperature protection by breaking electrical contact when a
specified temperature is reached.
Honeywell manufactures a wide range of 12,7 mm [0.5 in]
commercial snap-action thermostats for possible use in a wide
array of small and major appliances, office copy machines,
medical equipment, heat detectors, HVAC equipment and
more.
These snap-action thermostats include automatic and manual
reset options, phenolic or ceramic housings and a wide variety
of mounting brackets and terminal options.
Each thermostat's design is configured from a base unit, and
may be customized for temperature tolerance and mechanical
configurations, meeting the customer’s needs for accuracy and
exactitude.
Honeywell can also integrate these thermostats in higher value
cable assemblies, incorporating wire harness and connectors.
TABLE OF CONTENTS
DESCRIPTION
NOMENCLATURE
DEFINITION OF TERMS
NOTES
COMMERCIAL THERMOSTATS
2450R/2450HR/2455R/2452R/2452HR Series Phenolic Automatic Reset
2450RC/2450RCH/2455RC Series Ceramic Automatic Reset
2455RM/2450CM Series Phenolic or Ceramic Manual Reset
2455RD Series Phenolic Manual Reset
2455RBV Series Overmolded Automatic Reset
2450A/2455RA Series Heat Detection
2450R/2455R/2450RC/2455RC/2450HR/2450RCH Series “One Shot”
REDI-TEMP THERMOSTATS
3455RC Series
MOUNTING HARDWARE
Brackets
Brass mounting studs
Terminals
p. 1
p. 2
p. 3
p. 3
p. 4
p. 6
p. 9
p. 11
p. 13
p. 15
p. 17
p. 19
p. 20
p. 21
p. 22
Commercial Thermostats
NOMENCLATURE
The nomenclature given in Figure 1 is provided for reference only.
Figure 1. Commercial Thermostat Nomenclature
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DEFINITION OF TERMS
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Automatic Reset:
A type of thermostat that will automatically reset at a specific temperature (i.e. a thermostat operates at
o
o
o
o
65,5 C [150 F] and resets at 48,89 C [120 F]).
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Bimetal:
Two dissimilar metals bonded together to form the material for manufacturing thermally-sensitive discs which actuate
the thermostat.
Close on Rise (COR):
Refers to operation of the contacts. When the temperature rises to its set point, the contacts close or
make contact and complete the circuit.
Contact Resistance:
The value of resistance measured between the terminals.
Dielectric Strength:
The value of insulation between two electrically conducting parts. It may be tested by the application of a
predetermined overvoltage for a specified time.
Differential:
The temperature difference between the operate and reset set points, also known as operate and reset.
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Nominal:
The temperature difference between nominal set points regardless of tolerance.
Maximum:
Maximum number of degrees between actual opening and closing set points.
Minimum:
Minimum number of degrees between actual opening and closing set points.
Exposure Temperature:
Thermal environment of a device during application operation.
FLA (Full Load Amps):
Current taken from the line by the motor when the motor is yielding the rated hp at the rated voltage
and frequency.
Life Cycles:
The endurance rating of the thermostat expressed in number of operations with stated electrical load applied.
Temperature limit application = open on rise.
LRA (Locked Rotor Amps):
The amount of current the motor can be expected to draw under starting conditions when full
voltage is applied, also known as starting inrush current.
Manual Reset:
A bimetal thermostat with a reset button that must be pressed to reset the contacts.
Open on Rise (OOR):
Refers to the operation of contacts. When the temperature rises to its set point the contacts open,
terminating the circuit.
Overmold:
Encapsulation with an insulating material.
Phenolic:
Thermoset plastic used for the insulating body of the thermostat.
Set Point:
The nominal temperature at which the thermostat operates.
SPST (Single Pole/Single Throw):
A switch with one current path which can be either open or closed.
Tolerance:
The allowable range above and below the set point temperature.
Operate:
Change of state when the thermostat reaches its set point.
Reset:
Change of state when the thermostat returns to its original condition prior to operation.
NOTES
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Standard Temperature Characteristics Tables:
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Temperatures:
Please consult applications engineering for temperature ranges, tolerances and differentials not noted.
The operating temperature ranges include tolerances.
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Tolerances:
The ± tolerances given have been established after review of many thermostat applications. Attempts should
be made to establish the widest acceptable tolerance possible.
UL and CSA Approvals:
12,7 mm [0.5 in] thermostats are available with multiple agency approval for incorporation into
equipment.
Fan control applications:
Require thermostat set points to be derated by 20 °C from the equivalent temperature limit
application. They also close on rise.
Dimensions:
Are for reference only and are given in mm [in].
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Commercial Thermostats
Figure 2. 2450R/2450HR/2455R/2452R/2452HR Series Phenolic Automatic Reset Thermostat
The 2450R/2450HR/2455R/2452R/2452HR Series is a
single pole, single throw, snap-acting, non-adjustable
thermostat which may be used in applications such as
power supplies, general appliances and medical equipment.
A temperature-sensitive bimetal disc, electrically and
thermally isolated from the switch, is used to actuate the
normally-closed contacts. Contacts open when surface or
ambient temperatures increase to the operating set point of
the calibrated bimetal disc. The entire switch is enclosed in
a phenolic housing; the bimetal disc is retained by a metal
heat-conducting end cap. Due to the small size of this unit
and the inherently low mass of the bimetal snap-action disc,
response of this thermostat to temperature changes is
extremely rapid, compared to other commercially available
thermostatic devices. A variety of mounting brackets and
terminals are available.
All versions are UL/CSA approved.
The 2452R/2452HR/2455R version meets the requirements of
EN60730-01.
Potential applications include:
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Power supplies
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Appliances
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Medical equipment
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Water heaters
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Office automation
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Industrial equipment
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HVAC equipment
Table 1. 2450R/2450HR/2455R/2452R/2452HR Series Standard Temperature Characteristics
Standard Mean Differential
Operating Temperature Range
Tolerance
°C [°F]
Open
Close
°C [°F]
°C [°F]
±4 [±7]
±4 [±6]
±4 [±6]
±4 [±6]
±3 [±5]
±5 [±9]
±4 [±7]
±4 [±6]
±3 [±5]
±3 [±5]
±3 [±5]
±6 [±10]
±5 [±8]
±4 [±7]
±4 [±6]
±4 [±6]
±4 [±6]
±7 [±12]
±5 [±9]
±5 [±8]
±4 [±7]
±4 [±7]
±4 [±7]
±6 [±10]
±6 [±10]
±5 [±9]
±5 [±8]
±5 [±8]
±8 [±15]
±6 [±11]
±6 [±10]
±6 [±10]
±5 [±9]
±5 [±8]
±8 [±15]
±8 [±15]
±7 [±12]
±6 [±10]
±5 [±9]
±5 [±8]
±10 [±18]
±8 [±15]
±7 [±12]
±7 [±12]
±6 [±11]
±6 [±10]
28 to 34 [50 to 60]
22 to 27 [40 to 49]
17 to 22 [30 to 39]
14 to 16 [25 to 29]
8 to 14 [15 to 24]
45 to 56 [81 to 100]
34 to 45 [61 to 80]
28 to 34 [50 to 60]
22 to 27 [40 to 49]
17 to 22 [30 to 39]
8 to 16 [15 to 29]
45 to 56 [81 to 100]
34 to 45 [61 to 80]
28 to 34 [50 to 60]
22 to 27 [40 to 49]
17 to 22 [30 to 39]
8 to 16 [15 to 29]
45 to 56 [80 to 100]
34 to 45 [61 to 80]
28 to 34 [50 to 60]
22 to 27 [40 to 49]
17 to 22 [30 to 39]
14 to 16 [25 to 29]
0 °C to 26 °C
[32 °F to 79 °F]
27 °C to 82 °C
[80 °F to 180 °F]
83 °C to 110 °C
[181 °F to 230 °F]
111 °C to 150 °C
[231 °F to 302 °F]
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Table 2. 2450R/2450HR/2455R/2452R/2452HR Series Specifications
Characteristic
Parameter
Switch type
SPST
Reset type
automatic
Amperage
See Tables 3, 4
Voltage
120 Vac to 250 Vac
Operating temperature range
0 °C to 150 °C [32 °F to 302 °F]
Environmental exposure range -18 °C to 177 °C [0 °F to 350 °F]
Materials:
phenolic
Base
silver alloy
Contacts
unplated brass, plated brass or steel
Terminals
aluminum, brass or stainless steel
Closure
Brackets
aluminum or stainless steel
UL and CSA approvals
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2455R: 6,35 mm [0.25 in] clearance; UL File MH8267, UL File E36103; CSA File LR21048
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2450HR: 1,59 mm [0.0625 in] clearance; UL File E36103; CSA File LR21048
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2450R: 1,59 mm [0.0625 in] clearance; UL File E36103; CSA File LR 21048
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2452R: 2.66mm [0.105 in] clearance; UL E36103
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2452HR: 2.66mm [0.105 in] clearance; UL36103
Weight
6 g [0.2 oz] (does not include brackets or wire leads)
Table 3. 2450R/2450HR/2452R/2452HR Contact Ratings
Life Cycles
120 Vac
100,000
15 A resistive
30,000
125 VA pilot duty
Note:
2450 approval rating is limited by EN60730-1 to 125 Vac max.
Table 4. 2455R Contact Ratings
Life Cycles
100,000
240 Vac
10 A resistive
125 VA pilot duty
277 Vac
10 A resistive
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120 Vac
240 Vac
15 A resistive
10 A resistive
4.4 FLA 26.4 LRA
2.2 FLA 13.2 LRA
125 VA pilot duty
125 VA pilot duty
6,000
5.8 FLA, 34.8 LRA
2.9 FLA, 17.4 LRA
Note:
Additional contact ratings are available, please contact Honeywell.
Figure 3. 2450R/2450HR/2455R/2452R/2452HR Basic Dimensions
2450R
2450HR
277 Vac
7.2 A resistive
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2455R
2452R
2452HR
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