How does a bimetallic disc temperature switch work?

Series 11 temperature switches use a bimetallic disc — two metals with different thermal expansion coefficients bonded together — that snaps from one shape to another at a precise factory-set temperature. This snap-action movement opens or closes an electrical contact. The mechanism is entirely mechanical, requires no external power, and provides repeatable switching with a built-in hysteresis band that prevents contact chatter near the trip point.

What is the difference between close-on-rise and open-on-rise?

Close-on-rise (COR) switches have contacts that are normally open at ambient temperature and close when the sensed temperature reaches the factory-set trip point — ideal for activating alarms, fans, or cooling systems when overheating occurs. Open-on-rise (OOR) switches have contacts that are normally closed at ambient and open at the trip point — commonly used to shut down heaters, pumps, or equipment when a safe temperature limit is exceeded.

What temperature setpoints are available?

Series 11 temperature switches offer 16 factory-set setpoint codes (A through P) covering a range from 0°C to 100°C. Eight codes (A–H) are opens-on-rise (normally closed) and eight codes (I–P) are closes-on-rise (normally open). Each setpoint is a distinct part number — no field adjustment is required or possible.

What is the minimum order quantity?

There is no minimum order. Series 11 products are available in 1-pack and 10-pack configurations with tiered pricing. Volume OEM pricing for quantities above published tiers is available on request. All products ship Wednesdays from Paradise, California.

ERECTA SWITCH® | Series 11 Temperature Switches

Bimetallic Disc Temperature Switching
for Precision Thermal Protection

Q: What is the difference between Temperature Switch Sets and Temperature Probe Sets?

Temperature Switch Sets are compact, self-contained assemblies that mount directly without requiring an additional precision nipple. Temperature Probe Sets use the 10-715 Precision Nipple (ordered separately) to set the sensing depth from 1 inch to 70 inches below the mounting point. Both categories use the same bimetallic disc sensing element and are available in all three materials.

Q: Can Series 11 temperature switches be integrated with Series 10 level switches?

Yes. Series 11 temperature switches use the same 1/8-inch NPT thread and are fully compatible with Series 10 extended stem assemblies. On two, three, and four-level configurations, any level position can be substituted with a Series 11 temperature switch — allowing combined level and temperature monitoring through a single tank penetration using the same modular hardware.

Nineteen model configurations across two categories — Temperature Switch Sets and Temperature Probe Sets. Close-on-rise and open-on-rise contact forms. Factory-set setpoints from 0°C to 100°C. Three chemical-resistant materials. Fully compatible with Series 10 extended stem assemblies.

Model Numbers

Temperature Setpoints

Materials

0–100°C

Setpoint Range

Browse by Model

All 19 Series 11 Temperature Switch Models

All models use the same bimetallic disc sensing element. Select any model to view available materials, pack sizes, and pricing.

Temperature Switch Sets — 11 Models

Self-contained sets. No 10-715 Precision Nipple required.

11-800

Base Switching Element (1/8″ NPT)

PP · AC · KR

View Details →

11-805

Compact Dual-Thread Bulkhead

PP · AC · KR

View Details →

11-805-R

Compact Dual-Thread + Receptacle

PP · AC · KRReceptacle

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11-888

Compact Angle with O-Ring

PP · AC · KR

View Details →

11-888-R

Compact Angle + Receptacle

PP · AC · KRReceptacle

View Details →

11-892

1/4″ NPT Bulkhead Mount

PP · AC · KR

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11-892-R

1/4″ Bulkhead + Receptacle

PP · AC · KRReceptacle

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11-893-R

1-1/4″ NPT + Receptacle

PP · AC · KRReceptacle

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11-894-R

2″ NPT Adapter + Receptacle

PP · AC · KRReceptacle

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11-895

Compact Snap-In Bracket

PP · AC · KR

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11-895-R

Snap-In Bracket + Receptacle

PP · AC · KRReceptacle

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Temperature Probe Sets — 8 Models

Extended-stem assemblies. Require 10-715 Precision Nipple (ordered separately) to set sensing depth.

11-801

Bulkhead Vertical Mount

PP · AC · KR10-715 Nipple

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11-801-R

Bulkhead Vertical + Receptacle

PP · AC · KRReceptacle10-715

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11-802

1-1/4″ NPT Receptacle Mount

PP · AC · KR10-715 Nipple

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11-803

2″ NPT Adapter

PP · AC · KR10-715 Nipple

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11-809

Snap Bracket Pipe Mount

PP · AC · KR10-715 Nipple

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11-809-R

Snap Bracket + Receptacle

PP · AC · KRReceptacle10-715

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11-810

Angle Connector Wall Mount

PP · AC · KR10-715 Nipple

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11-810-R

Angle Connector + Receptacle

PP · AC · KRReceptacle10-715

View Details →

Series 11 Bimetallic Disc Temperature Switch

How It Works

Bimetallic Disc Snap-Action Switching

Series 11 temperature switches use a bimetallic disc — two metals with different thermal expansion coefficients bonded together — that snaps from one shape to another at a precise factory-set temperature. This mechanical snap-action provides clean, positive switching without contact chatter and requires no external power source.

✓16 factory-set setpoints — codes A through P covering 0°C to 100°C. Opens-on-rise and closes-on-rise. No field adjustment required.
✓Close-on-rise & open-on-rise — both contact forms available. COR activates a circuit on overtemperature; OOR breaks a circuit.
✓Built-in hysteresis — the disc resets at a lower temperature than the trip point, preventing rapid cycling near the setpoint.
✓Series 10 compatible — same 1/8″ NPT thread. Substitutes into any level position on multi-level extended stem sets.

See Series 10 Integration →

Specifications

Common Ratings — All Series 11

All 19 configurations share the same core bimetallic disc ratings. Material selection affects chemical compatibility only.

6A · 120V

Electrical Rating AC (Resistive)

0–100°C

Setpoint Range (16 Codes)

Factory-Set Setpoints (A–P)

COR / OOR

Contact Forms Available

1/8″ NPT

Thread Size

50 PSI

Max Pressure @ 20°C

Snap-Action

Switching Mechanism

RoHS

Compliance

Model	Name	Mount Type	PP	AC	KR	10-715	Receptacle
Temperature Switch Sets (11 Models)
11-800	Base Switching Element	1/8″ NPT Direct	✓	✓	✓	—	—
11-805	Compact Dual-Thread Bulkhead	1/4″ & 1/2″ NPT	✓	✓	✓	—	—
11-805-R	Compact Dual-Thread + Receptacle	1/4″ & 1/2″ NPT	✓	✓	✓	—	✓
11-888	Compact Angle with O-Ring	0.406″ Hole + O-Ring	✓	✓	✓	—	—
11-888-R	Compact Angle + Receptacle	0.406″ Hole	✓	✓	✓	—	✓
11-892	1/4″ NPT Bulkhead Mount	1/4″ NPT Direct	✓	✓	✓	—	—
11-892-R	1/4″ Bulkhead + Receptacle	1/4″ NPT	✓	✓	✓	—	✓
11-893-R	1-1/4″ NPT + Receptacle	1-1/4″ NPT	✓	✓	✓	—	✓
11-894-R	2″ NPT Adapter + Receptacle	2″ NPT	✓	✓	✓	—	✓
11-895	Compact Snap-In Bracket	Snap-In Bracket	✓	✓	✓	—	—
11-895-R	Snap-In Bracket + Receptacle	Snap-In	✓	✓	✓	—	✓
Temperature Probe Sets (8 Models) — Require 10-715 Precision Nipple
11-801	Bulkhead Vertical Mount	Bulkhead Fitting	✓	✓	✓	✓	—
11-801-R	Bulkhead Vertical + Receptacle	Bulkhead	✓	✓	✓	✓	✓
11-802	1-1/4″ NPT Receptacle Mount	1-1/4″ NPT	✓	✓	✓	✓	✓
11-803	2″ NPT Adapter	2″ NPT	✓	✓	✓	✓	—
11-809	Snap Bracket Pipe Mount	Snap Bracket	✓	✓	✓	✓	—
11-809-R	Snap Bracket + Receptacle	Snap Bracket	✓	✓	✓	✓	✓
11-810	Angle Connector Wall Mount	Angle Connector	✓	✓	✓	✓	—
11-810-R	Angle Connector + Receptacle	Angle	✓	✓	✓	✓	✓

Material Options

Three Chemical-Resistant Materials

All 19 Series 11 models are available in three thermoplastic materials. Select based on the fluid chemistry in your application.

PP — Polypropylene

General Purpose · Gray Body

Water, soaps, coolants, dilute acids, and alkaline cleaning solutions. The standard specification for aqueous applications. Lowest cost per unit.

AC — Acetal

Hydrocarbons · Red Body

Gasoline, diesel, hydraulic oil, motor oil, kerosene, and petroleum-based fluids. The correct specification when polypropylene is incompatible with the fluid chemistry.

KR — Kynar PVDF

Aggressive Chemicals · Natural Body

Concentrated acids, caustics, oxidizers, halogens, and high-purity process fluids. The highest-performance Series 11 specification for demanding chemical environments.

Use Cases

Temperature Switch Applications

Series 11 bimetallic disc switches provide reliable overtemperature protection and thermal monitoring across OEM and industrial applications.

⚠

Overtemperature Alarm & Shutdown

Safety Critical

Activate audible or visual alarms, or shut down equipment entirely, when fluid temperature exceeds a safe operating limit. Open-on-rise setpoint codes (A–H) break the circuit to de-energize heaters, pumps, or compressors.

Opens-on-RiseCodes A–H

⚙

Cooling System Activation

Process Control

Close-on-rise setpoint codes (I–P) energize cooling fans, solenoid valves, or circulation pumps when fluid temperature reaches the setpoint. Automatic reset when temperature drops below the hysteresis band.

Closes-on-RiseCodes I–P

💧

Combined Level + Temperature Monitoring

Multi-Function Sensing

Integrate a Series 11 temperature switch into any level position on a Series 10 multi-level extended stem set. Monitor both liquid levels and temperature limits through a single tank penetration.

All S11 Models+ Series 10

🔌

Adjustable-Depth Temperature Probing

Temperature Probe Sets

Temperature Probe Sets use the 10-715 Precision Nipple to position the bimetallic disc at any depth from 1″ to 70″ below the mounting point. NL (Nipple Length) is calculated from the installation drawing.

11-80111-80211-803+ 5 more

Common Questions

Series 11 FAQ

A bimetallic disc is made of two metals with different thermal expansion rates bonded together. As the temperature rises, differential expansion causes the disc to snap from one shape to another at a precise, factory-calibrated trip point. This snap-action movement opens or closes an electrical contact. The mechanism is entirely mechanical, requires no external power, and provides repeatable switching with a built-in hysteresis band that prevents contact chatter near the setpoint.

Close-on-rise (COR) switches have contacts that are normally open at ambient temperature and close when the sensed temperature reaches the factory-set trip point — ideal for activating alarms, fans, or cooling systems. Open-on-rise (OOR) switches have contacts that are normally closed at ambient and open at the trip point — commonly used to shut down heaters, pumps, or equipment when a safe temperature limit is exceeded. Setpoint codes I–P are close-on-rise; codes A–H are open-on-rise.

Series 11 temperature switches offer 16 factory-set setpoint codes (A through P) covering a range from 0°C to 100°C. Each setpoint code is a distinct part number suffix. No field adjustment is required or possible, ensuring repeatable, tamper-proof operation.

Temperature Switch Sets (11 models) are compact, self-contained assemblies that mount directly without requiring an additional precision nipple. Temperature Probe Sets (8 models) use the 10-715 Precision Nipple (ordered separately) to set the sensing depth from 1″ to 70″ below the mounting point. Both categories use the same bimetallic disc sensing element, the same 16 setpoint codes, and are available in all three materials (PP, Acetal, Kynar PVDF).

Yes. Series 11 temperature switches use the same 1/8″ NPT thread and are fully compatible with Series 10 extended stem assemblies. On multi-level configurations, any level position can be substituted with a Series 11 temperature switch — allowing combined level and temperature monitoring through a single tank penetration.

No minimum. Series 11 products are available as single units or in 10-packs with tiered pricing. OEM pricing for quantities above published tiers is available on request. All products ship Wednesdays from Paradise, California.

Bimetallic Disc Temperature Switchingfor Precision Thermal Protection

All 19 Series 11 Temperature Switch Models

Temperature Switch Sets — 11 Models

Temperature Probe Sets — 8 Models

Bimetallic Disc Snap-Action Switching

Common Ratings — All Series 11

Three Chemical-Resistant Materials

General Purpose · Gray Body

Hydrocarbons · Red Body

Aggressive Chemicals · Natural Body

Temperature Switch Applications

Overtemperature Alarm & Shutdown

Cooling System Activation

Combined Level + Temperature Monitoring

Adjustable-Depth Temperature Probing

Series 11 FAQ

Ready to Specify?

Bimetallic Disc Temperature Switching
for Precision Thermal Protection