Finding the right thermal switch for a heater means matching compatibility, reset behavior, and temperature rating. The table below summarizes the key options selected for Bradford White water heaters, pool heater rollout protection, and general-purpose bimetal thermostat switches suitable for heater controls.
| Product | Type | Key Feature | Use Case |
|---|---|---|---|
| 239-43676-03 Resettable Thermal Switch | Resettable High Temp Limit | Auto Reset At 290°F | Bradford White Water Heaters |
| Bradford White 239-43676-03 Thermal Switch (OEM) | OEM Resettable Limit | Genuine Manufacturer Part | Direct OEM Replacement |
| 2394367602 Resettable Thermal Switch (MZCTD) | Resettable Cutoff (KSD301) | 130°C (266°F) Rating | Bradford White Models, General Heater Safety |
| Dreyoo 152°C Thermal Cut Off Fuse | One-Time Thermal Fuse | 152°C, 250V 15A | Pool Heaters & Rollout Protection |
| Awozkcd UL/CUL KSD301 Shutoff Thermostat | Bimetal Snap Disc Thermostat | 40°C On / 30°C Off Auto Reset | General Exhaust Fan / Low-Temp Heater Controls |
Content Navigation
- 239-43676-03 Resettable Thermal Switch 290F
- Bradford White 239-43676-03 Thermal Switch
- 2394367602 Resettable Thermal Switch For Bradford White
- Dreyoo 152°C Thermal Cut Off Fuse For Pool Heater
- Awozkcd UL/CUL KSD301 Shutoff Thermostat 40°C/30°C
- Buying Guide: How To Choose The Right Thermal Switch For Your Heater
- 1. Identify Application And Type
- 2. Confirm Compatibility And Fit
- 3. Temperature Rating And Trip Behavior
- 4. Electrical Ratings
- 5. Certification And Safety Standards
- 6. Reset Mechanism And Serviceability
- 7. Environmental And Mechanical Factors
- 8. Comparison Perspectives
- 9. Installation And Verification
- 10. When To Consult A Professional
239-43676-03 Resettable Thermal Switch 290F
This replacement thermal switch is listed as compatible with several Bradford White water heater models and is described as a resettable overheat protector that trips at 290°F. It’s positioned as a common fix when a heater shuts off randomly or fails to produce hot water. The design restores power automatically after cooling, fitting applications that require a reusable safety cutoff rather than a one-time thermal fuse.
- Compatibility: Fits MI-404T6FBN, 50T65F, MI-30T6FBN, MI-303T6FBN2, MI40T6FBN2 and similar models.
- Trip Temperature: 290°F (listed as overheat protection).
- Reset Type: Auto-reset after cooldown—useful for troubleshooting intermittent trip conditions.
- Application: Water heater high-temperature cutoff / overheat protection.
Bradford White 239-43676-03 Thermal Switch
This listing identifies the part as a Genuine OEM replacement for Bradford White water heaters carrying the 239-43676-03 part number. OEM parts may match factory tolerances and form-fit more precisely than aftermarket options. The description is concise, indicating direct replacement status which is important when validating fit and serviceability in warranty or maintenance contexts.
- OEM Status: Genuine Bradford White replacement part number 239-43676-03.
- Fitment: Intended as a direct swap for matching model numbers and mounting points.
- Use Case: Water heater overheat cutoff where factory part equivalence is required.
2394367602 Resettable Thermal Switch For Bradford White
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This resettable thermal switch replaces part numbers 2394367602 and 415-43676-02 and is described with a KSD301 element rated at 130°C (266°F), 250V, 16A. It’s presented as compatible with many Bradford White models and suitable for residential and commercial applications. The KSD301 designation indicates a bimetal snap-action thermal control commonly used as a high-limit or cutoff.
- Temperature Rating: 130°C (266°F) typical trip for listed KSD301 parts.
- Electrical Rating: 250V, 16A for resistive loads (per listing).
- Compatibility: Lists numerous Bradford White model numbers—verify model details before purchase.
- Reset Behavior: Auto-reset after temperature falls below release threshold.
Dreyoo 152°C Thermal Cut Off Fuse For Pool Heater
This product is a one-time thermal fuse rated at 152°C and specified for use with Raypak and Zodiac pool heater parts, including rollout switch replacements. Unlike resettable switches, this fusible link is designed to permanently open when its rated temperature is exceeded. It’s commonly used in applications where a single-use fail-safe is preferred to ensure clear evidence of an overheat event.
- Type: Non-resettable thermal fuse / fusible link.
- Rating: 152°C, 250V, 15A.
- Application: Pool heater rollout protection, auxiliary overheat points.
- Replacement Use: Matches Raypak 005899F and Zodiac R0012200 part references.
Awozkcd UL/CUL KSD301 Shutoff Thermostat 40°C/30°C
The Awozkcd KSD301 is a small bimetal snap-disc thermostat with UL/CUL approval and specified action as Normally Open (N.O.). The temperature points listed are 40°C On / 30°C Off with ±3°C tolerance, making it suitable for low-temperature heater control, fan cut-ins, and small appliance thermal control. It supports a range of voltage/current ratings for AC and DC loads.
- Action Type: Normally Open, closes on temperature rise.
- Ratings: AC110-125V 16A, 250V up to 16A depending on variant; DC ratings listed for lower currents.
- Certifications: UL/CUL (E527363) listed for safety compliance.
- Use Cases: Exhaust fans, auxiliary heater control, small appliances, or as a sensor in larger systems.
Buying Guide: How To Choose The Right Thermal Switch For Your Heater
Selecting a thermal switch or thermal fuse requires matching electrical, thermal, and mechanical characteristics to your heater system. Below are the key considerations and comparison perspectives to guide a correct choice.
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1. Identify Application And Type
Decide whether you need a resettable thermal switch (auto-reset bimetal high-limit) or a one-time thermal fuse (fusible link). Resettable switches restore circuit continuity after cooling and are often used for intermittent trips and diagnostics. One-time fuses provide irreversible protection useful where a permanent indication of overheat is preferred.
2. Confirm Compatibility And Fit
Match OEM part numbers, model lists, and mounting style. For Bradford White heaters, verify the model and part (e.g., 239-43676-03, 2394367602) to ensure physical and electrical fit. OEM parts reduce fitment risk but aftermarket parts can be equivalent if cross-referenced correctly.
3. Temperature Rating And Trip Behavior
Check the listed trip temperature and release hysteresis. KSD301 style switches often have defined trip and reset points. For water heater high-limit use, typical trip values range from ~130°C (266°F) to higher temperatures; some products list 290°F as the trip. For rollout or element protection, choose the temperature rating that aligns with factory specifications.
4. Electrical Ratings
Verify voltage and current ratings for both resistive and inductive loads. Typical ratings include 250V 16A for many KSD301 switches. If your heater uses higher starting currents or motor loads, confirm the switch contacts are rated for those conditions or add a relay/contact to handle heavy currents.
5. Certification And Safety Standards
Look for UL/CUL listings or OEM approvals when available. Certified switches provide documentation for safety compliance and reduce uncertainty in regulated installations. For pool and spa heaters, ensure the replacement matches manufacturer-recommended parts for safety and insurance considerations.
6. Reset Mechanism And Serviceability
If frequent trips are expected during diagnosis, a resettable switch can save time. For final repairs, evaluate whether a one-time fuse is preferred to enforce a permanent repair after an overheat event. Consider accessibility and whether the part requires removal of panels or gas/electric disconnects for replacement.
7. Environmental And Mechanical Factors
Consider ambient temperature, vibration, and exposure to moisture. Some bimetal switches are sealed; others are open and may corrode. Pool heater parts should resist outdoor or humid conditions. For mobile or RV heaters, look for vibration-resistant construction.
8. Comparison Perspectives
- OEM vs Aftermarket: OEM parts improve fit and factory compliance; aftermarket can be cost-effective when specs match.
- Resettable vs One-Time: Resettable for troubleshooting and non-destructive protection; one-time fuses for irreversible safety events.
- High-Temperature vs Low-Temperature Controls: Use low-temp thermostats (e.g., 40°C) for fan controls and small appliances; use high-temp cutoff switches (130°C/152°C/290°F) for heater element or combustion chamber protection.
- Contact Ratings: Confirm contact capacity for resistive heaters vs motors—use relays if needed to isolate heavy inductive loads.
9. Installation And Verification
Always disconnect power and follow manufacturer instructions. After installation, verify trip and reset behavior according to safe test procedures. Document the replacement part and keep the old part for troubleshooting if appropriate.
10. When To Consult A Professional
Consult a qualified technician when the heater is under warranty, when gas or combustion systems are involved, or if electrical connections and load characteristics are unclear. Professional service ensures correct safety device selection and compliance with local codes.
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