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GENERAL
INFORMATION
www.white-rodgers.com220
TECHNICAL HELP
SERIES
100
800
3600
Allows for up to 100 basic models in each series
MODEL
165
848
3603
Basic model number within a series
MODEL
1A65
8B48
36C03
Letter after first or second digit of Model
number identifies another control model after
the basic model, which allows expansion of the
numbering system
MODEL
8B48A 36C03U Letter after Model number (or absence of letter)
identifies operator coil voltage* (see table below)
TYPE
1A65-641 8B48A-217 36C03U-333 Dash number identifies a specific device within a
control model. Model number plus dash number/
type number
1939-1962 — Letter indicated year of manufacture
— 1 or 2 digit number (1-52) indicated week of manufacture
Example
:
X49
was the 49th week of 1959
1963-1975 — First 1 or 2 digit number indicated month of manufacture (1-12)
— Following two digit number indicated year of manufacture (63-75)
— Letter following numbers indicated week of manufacture (A-E)
Example
:
1175C
was the 3rd week of November, 1975
1976-present — First two digits indicate year of manufacture (15-20)
— Last two digits indicate week of manufacture (15-20)
Example
:
1520
was the 20th week of 2015
Series Control Category
2400 Sequencers and Time Delay Relays
2500 Solenoid Gas Valves
3000 Mercury Flame Sensors
3400 Commercial Motor Actuators
3600 Combination Gas Manifold Valves
3700 Gas Water Heater Controls
3900 Commercial Economizers
5000 Ignition Components
Series Control Category
900 Flame Detectors
1000 Temperature Controls
1100 Hot Water Controls
1300 Zone Valves and Hydronics
1600 Refrigeration Temperature Controls
1700 Refrigeration Temperature Controls
2000 Motorized Zone Dampers
2100 Pre-Packaged Kits
A GUIDE TO THE WHITE-RODGERS NUMBERING SYSTEM
Older models start with the dash in the basic Model Number, then working to the left, eliminate all letters. The number remaining will give you
the Series and Control Category listed in the box below.
Example:
1F56-301
Leave out the letter
F
, the number remaining is
156
or a
100 Series
of Room Thermostats
Example:
21D18-3
Leave out the letter
D
, the number remaining is
2118
or a
2100 Series
of Pre-Packaged Kits
WHITE-RODGERS
NUMBERING SYSTEM
Series Control Category
100 Room Thermostats
200 Space Thermostats
300 Fan or Limits
400 Limits, Fans and Temperature Controls
500 Fan, Limit or Fan and Limits
600 Oil Controls
700 Miscellaneous Controls
800 Relays
MODEL AND TYPE NUMBER EXAMPLES
Vertical Horizontal Example
Snap Action
C
D 1C30, 1D35
Contacts
*Mercury Bulb E
F 1E30, 1F56
Switch
SINGLE STAGE
MECHANICAL
LOW VOLTAGE
THERMOSTAT LEGEND
Code *
Voltage
Voltage Designations on Gas Valves & Switching Relays
No Letter
24 VAC
No Letter —
24 VAC
36C03-333
A
120 VAC
Letter A —
120 VAC
36C03A-310
E
208 VAC
Letter E —
208 VAC
24A06E-1
G
240 VAC
Letter G —
240 VAC
24A06G-1
U
750mv DC
Letter U —
750mv DC
36C03U-333
Z
SPECIAL
Letter Z —
SPECIAL
24A06Z-1
COMMENTS
* These designations only apply to power consuming devices that operate at a specific voltage (relays,
solenoids, gas valves, motors, etc.) They are not used with thermostats or temperature controls.
VOLTAGE DESIGNATIONS (60 Hz)
PIPE SIZE
SUFFIX NO.
3
/
8
x
3
/
8
1 thru 49
1
/
2
x
1
/
2
INV. FL.
50 thru 74
3
/
4
x
1
/
2
75 thru 90
1
/
2
x
3
/
8
100 thru 199
1
/
2
x
1
/
2
200 thru 299
1
/
2
x
3
/
4
300 thru 399
3
/
4
x
3
/
4
400 thru 499
pipe size DESIGNATIONS
(Gas valves only)
Year
Code
Year
Code
Year
Code
Year
Code
1939
A
1945
G
1951
N
1957
V
1940
B
1946
H
1952
P
1958
W
1941
C
1947
J
1953
R
1959
X
1942
D
1948
K
1954
S
1960
Y
1943
E
1949
L
1955
T
1961
Z
1944
F
1950
M
1956
U
1962
AA
A GUIDE TO THE WHITE-RODGERS DATE CODING SYSTEM
*Mercury bulb thermostats are no longer
produced. See current models for specifications.