stemco
351 Stemco Capillary Thermostats
The 351 Stemco Capillary Thermostats are our most versatile line of remote sensing thermostats, available in both Bulb & Capillary Tube & probe styles. Each style offers a variety of configurations, including fixed or adjustable temperatures, auto or manual resets, & your choice of Copper/Plated Copper or Stainless Steel construction. Additionally, all variations come with multiple mounting options, ensuring compatibility for a wide range of applications.
quality ambient compensation
Our capillary thermostats feature ambient compensation to offset temperature differentials, ensuring greater accuracy as environmental conditions change. This technology helps maintain reliable temperature control, even in fluctuating surroundings, making our thermostat controls ideal for dynamic applications.
CERTIFIED
Senasys ensures the quality control & reliable operation of all our products. Every capillary thermostat is 100% tested individually before leaving our facility to guarantee consistent performance. Our capillary thermostats are UL & cUL approved, meeting industry standards for safety & reliability.
CUSTOM OPTIONS
Senasys capillary thermostat switches are available as custom-built temperature control solutions, tailored to meet your exact specifications. This ensures you receive the precise capillary thermostat switch you need, without paying for unnecessary features, optimizing both performance & cost.
MADE IN U.S.A.
All Senasys products are designed, manufactured, tested, & shipped from our facilities in Eau Claire, WI to clients worldwide. Every switch is individually 100% tested for quality & performance before leaving our plant, ensuring reliable operation for every customer.
The STEMCO 351 series bulb and capillary thermostats are our most versatile. The series is available in several variations, including fixed and adjustable models with auto or manual reset. Numerous mounting options, bulb materials, and switch configurations enhance its adaptability.
The 351 series offers numerous mounting options that allow for simple replacement of competitor’s thermostats.
Every 351 thermostat is built to customer specifications. This ensures that you get the exact control you want without paying for features you don’t need.
Applications & Features of 351 Stemco Capillary Thermostats
Fixed temperature models are typically used in safety applications or high/low limit controls, ensuring reliable & accurate temperature regulation. The 351 Stemco series offers both probe style thermostats, ideal for boiler-type installations, & bulb & capillary tube style, preferred for remote temperature sensing.
The screwdriver adjustment model with its front connect terminals is perfect for warming ovens, deep fat fryers, and commercial water heaters.
The D-Shaft adjustable model allows for easy installation of a knob, making it ideal for applications such as convection ovens, charbroilers, dishwashers, grills, electric toasters and toaster ovens.
With multiple mounting options, these thermostats are compatible for simple replacement of competitor’s thermostats, providing an easy installation solution.
Key Specifications:
- Calibration temperature range of -40°F to 700°F
- Maximum ambient temperature of 250°F, optional ambient compensation
- available.
- Adjustable or Fixed Temperature Range options available
- Screwdriver or D-Shaft Adjustment.
- Automatic or Manual Reset
- SPDT Switch Action
- Rated for 15-25 Amps at 100,000 cycles
- Variety of capillary diameters and lengths available.
- Side, panel or back mounting options with front terminal locations. Housing
- optional, see boiler controls.
- Variety of Bulb & Capillary material options including, copper, dull nickel-
- plated copper, one piece stainless steel or two piece stainless steel.
- Variety of dial rotations available including 0°, 120°, 137°, 180° or 270°.
Durability & Protection
Built with polycarbonate thermoplastic construction, these thermostats are weatherproof, corrosion-resistant, & designed for enhanced durability & long-term performance, even in harsh environments. Unlike digital thermostats, 351 Stemco thermostats are not affected by power surges, lightning strikes, or power outages, ensuring uninterrupted temperature control.
Boiler & Probe Style Temperature Controls with Adjustable Settings & Auto Reset
These high-performance thermostat controls are designed for boiler applications, featuring adjustable temperature settings & auto reset functionality. Available in probe styles with various fittings, including 3/4″ NPT & 7/16″-24 Loxit, these thermostats provide precise temperature regulation in demanding industrial environments.
Each model is shown with optional thermowells & housing, ensuring protection & durability in harsh conditions. Select from fixed temperature or adjustable temperature models, with options for manual reset or auto reset to suit your specific temperature control needs.
Boiler Control with Adjustable Temperature Setting & Auto Reset. Shown with Thermowell & Housing.
Boiler Control with Adjustable Temperature Setting & Auto Reset. Shown with Thermowell.
Probe Style with Fixed Temperature & Manual Reset. Shown with 3/4″ NPT Fitting & Housing.
Probe Style with Adjustable Temperature Setting & Auto Reset. Shown with 3/4″ fitting.
Probe Style with Fixed Temperature & Auto Reset. Shown with 7/16″-24 Loxit Fitting (not standard).
Cross Reference
We’re confident in the quality & versatility of our 351 Stemco Bulb & Capillary Thermostats, which is why we’re comparing them against other top brands in the industry. Use this cross-reference guide to see how Stemco thermostats stack up against Selco, Peco, Robertshaw®, & E.G.O. models. Our thermostats offer a range of features such as adjustable temperatures, auto or manual resets, & a temperature range of 0°F to 700°F, ensuring reliable performance in a variety of industrial applications.
For a side-by-side comparison of how Senasys bulb & capillary thermostats measure up to competing models, view our cross-reference guide here .
BRANDS
STEMCO
351 Series
SELCO
CAP, CP MR or FS Series
PECO
T125, T103, L107, or L117 Series
ROBERTSHAW
C1 or LC Series
E.G.O.
EF Series
-40°F to 700°F Temperature Range
Fixed or Adjustable Setting
Screw Adjustment
D-Shaft Adjustment
250°F Max. Ambient Temperature
Auto or Manual Reset
Single-pole, Single-throw (SPST) or Single-pole, Double-throw (SPDT)
Screw Terminals
Wire Lead Options Available
Rated up to 25 Amps @ 250VAC
Copper or Stainless Steel Bulb & Capillary Material
UL / cUL Recognized
Made in U.S.A.
Mounting Options
Our single stage bulb & capillary thermostats are available with a screwdriver or D-Shaft adjustment knob, offering flexible mounting options: panel, side, or housed. All dimensions are listed below in inches/millimeters.
The screwdriver adjustment model with front connect terminals is ideal for applications such as warming ovens, deep fat fryers, and commercial water heaters. The D-Shaft adjustable model allows easy knob installation, making it perfect for equipment like convection ovens, charbroilers, dishwashers, grills, electric toasters, and toaster ovens. The fixed setting model is designed for safety limits where no user adjustments are needed.
Each 351 thermostat is custom-built to meet your exact temperature control specifications, ensuring you only pay for the features you need.
Most mounting brackets are interchangeable for easy installation.
Front Mounting Bracket, for Screw Driver Adjustable Model, with Auto Reset, 4 Hole Large Opening
Front Mounting Bracket, for D-shaft Adjustable Model with Auto Reset
Front Mounting Bracket, for or Fixed Setting Model with Manual Reset
Flat Side Mounting Bracket, shown with Fixed Setting Model with Manual Reset
Raised Side Mounting Bracket, shown with Fixed Setting Model with Manual Reset
Flat Base Mounting Bracket, shown with Fixed Setting Model with Auto Reset.
Fitting Options
Our Single Stage Bulb & Capillary Thermostats are available with a variety of standard fittings and bulb supports to ensure compatibility with a wide range of applications. Choose from multiple thread materials like brass or stainless steel, with different hex sizes, lengths, and finishes to meet your specific needs.
Below are the available fitting options for thread sizes ranging from 1/8 NPT to 1/2 NPT, ensuring a perfect fit for your equipment. See the complete list of available options and corresponding part numbers.
Standard Fittings
Thread
Material
Hex Size
‘L’ Length
Finish
Part #
1/8 NPT
Brass
7/16″
0.625″
None
368-67-03061
1/8 NPT
S-Steel
7/16″
0.625″
None
368-67-03023
1/4 NPT
Brass
5/8″
0.750″
None
368-67-03201
1/4 NPT
Brass
5/8″
0.750″
Nicked Plated
368-67-03202
1/4 NPT
S-Steel
5/8″
0.750″
None
368-67-03161
3/8 NPT
Brass
11/16″
0.750″
None
368-67-03001
3/8 NPT
Brass
11/16″
0.750″
Bright Nickel
368-67-03001P
3/8 NPT
S-Steel
11/16″
0.750″
None
368-67-03002
1/2 NPT
Brass
7/8″
0.875″
None
368-67-03101
1/2 NPT
Brass
7/8″
0.875″
Bright Nickel
368-67-03102
1/2 NPT
S-Steel
7/8″
0.875″
None
368-67-03103
Bulb Support Fittings
Our Single Stage Bulb & Capillary Thermostats are available with a variety of standard fittings & bulb supports to ensure compatibility with a wide range of applications. Choose from multiple thread materials like brass or stainless steel, with different hex sizes, lengths, & finishes to meet your specific needs.
Below are the available fitting options for thread sizes ranging from 1/8 NPT to 1/2 NPT, ensuring a perfect fit for your equipment. See the complete list of available options & corresponding part numbers.
Standard Bulb Support Fittings
Thread
Material
Hex Size
‘L’ Length
‘A’ Dia.
‘B’ Dia.
Finish
Part #
1/4 NPT
Brass
5/8″
1.620″
0.257″
0.390″
None
368-67-03241
1/4 NPT
S-Steel
5/8″
1.620″
0.147″
0.390″
None
368-67-03242
1/4 NPT
S-Steel
5/8″
1.620″
0.257″
0.390″
None
368-67-03243
1/2 NPT
S-Steel
7/8″
1.372″
0.257″
0.315″
None
368-67-03261
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