Pentair ETi 400 & ETi 250 Heater Thermal Switch Fuse 475998
Pentair
SKU: 475998
Pentair ETi 400 & ETi 250 Heater Thermal Switch Fuse | 475998
The Pentair 475998 Thermal Switch Fuse is a genuine OEM replacement safety component for compatible Pentair ETi 400 and ETi 250 high-efficiency swimming pool and spa heaters.
Designed for the heater's thermal protection system, this component helps protect the equipment by interrupting operation when specified thermal safety conditions are exceeded.
Pentair identifies part number 475998 as the thermal fuse used in its ETi heater systems. This is a replacement safety component, not a complete heater or control assembly.
Product Features
- Genuine Pentair OEM: Original manufacturer replacement component.
- ETi 400 Compatibility: Designed for Pentair ETi 400 high-efficiency gas heaters.
- ETi 250 Compatibility: Also specified for Pentair ETi 250 heaters.
- Thermal Safety Protection: Part of the heater's temperature safety system.
- OEM Fitment: Designed to replace the original Pentair 475998 component.
- Individual Replacement Part: Sold as one thermal switch fuse.
Product Specifications
- Manufacturer: Pentair
- Manufacturer Part Number: 475998
- Distributor SKU: PUR-151-0305
- Product Type: Thermal Switch / Thermal Fuse
- Color Identification: White
- Application: Pool and Spa Gas Heater Safety System
- Compatible Heater Models: ETi 400 and ETi 250
- UPC: 788379878108
- Package Quantity: 1 Thermal Fuse
Compatible Pentair Heaters
- Pentair ETi 400 High-Efficiency Gas Heater
- Pentair ETi 250 High-Efficiency Gas Heater
Compatibility Notice: Verify your heater model and the original component part number before ordering. Not all Pentair gas heaters use the same thermal protection components.
What Does the Thermal Fuse Do?
The thermal fuse is an important safety component within the heater's protection system.
It is designed to interrupt operation when the specified thermal safety conditions occur, helping protect the heater from potentially hazardous operating conditions.
A failed or open thermal fuse may prevent the heater from operating.
Because this component is part of the heater's safety system, the cause of a thermal fuse failure must be identified and corrected before the heater is returned to service.
When to Replace the Thermal Fuse
Replacement may be necessary when a qualified service technician confirms that the original thermal fuse has failed.
- The original thermal fuse has been diagnosed as open or defective.
- The component is physically damaged.
- The heater's service procedure specifies replacement.
- A qualified technician has identified and corrected the underlying cause of failure.
Safety: Never bypass, jumper, or defeat a heater thermal fuse. Doing so can create a serious fire or equipment safety hazard.
Related Pentair ETi Heater Parts
Find additional genuine Pentair heater replacement components at Aqua Pool Supply.
- Pentair 475601Z – Stack Flue Temperature Sensor – Replacement exhaust temperature sensor for compatible Pentair ETi heaters.
- Pentair ETi 400 Heater Parts Diagram – Identify thermal fuses, sensors, ignition components, and other replacement parts.
- Pentair ETi 250 Heater Parts Diagram – Browse model-specific ETi 250 heater components.
Installation and Safety
Installation should be performed by a qualified pool heater service technician following Pentair's official service instructions.
- Disconnect electrical power before servicing the heater.
- Shut off the gas supply when required by the service procedure.
- Allow the heater to cool completely.
- Diagnose the cause of the thermal fuse failure.
- Verify that Pentair 475998 is the correct replacement part.
- Install the replacement according to the manufacturer's instructions.
- Verify proper safety system operation before returning the heater to service.
Package Contents
Includes: One (1) Genuine Pentair 475998 Thermal Switch Fuse.
Not Included: Heater control board, wire harness, stack flue sensor, or complete heater.
Selling Quantity: 1 Thermal Fuse.
Questions about returns? View our return policy.
Hours Of Operation:
Monday - Friday: 7:00 am to 5:00 pm Phoenix Time
Saturday: 8:00 am to 2:00 pm
Sunday: Closed
- We do not ship on Saturday or Sunday.
- Orders totaling more than $300 will require signature confirmation upon delivery.
- We process and prepare orders for shipment within 1 business day. Please note that many other pool supply retailers require 3–5 days of handling time before shipping.
- Orders placed after 1:00 pm Phoenix Time may not be eligible for same-day shipment.
- Expedited shipping options are available at checkout.
Return Policy:
- Products that are received damaged will receive a refund in store credit.
- Most products are eligible for return within 30 days of receipt, except where noted below.
- To initiate a return, please complete an RMA form prior to sending your item back.
- Original shipping costs are non-refundable and will be deducted from the return credit.
- Items returned missing accessories or original packaging, or that are not in the same condition as received, may be subject to a restocking fee of up to 100% depending on the condition of the item upon return.
- Some returns will be charged an automatic 15% restocking fee.
- We are unable to issue refunds for items that have been damaged or rendered inoperable due to installer error.
- Please complete the return form to receive your RMA number and return shipping label.
- Chemical products are not eligible for return under any circumstances.
- The Pentair Colorsync 618031 is not eligible for return.
- Pool cleaners are not eligible for return.
- Opened seals and o-rings are not eligible for return.
- Capacitors are not eligible for return.
- Plastic popup tools are not eligible for return.
- Automation components and circuit boards are not eligible for return.
- If a light is returned due to a reported malfunction and is found to be fully operational upon testing, return shipping costs and a restocking fee will be deducted from the refund.
- Orders refused at the time of delivery will be subject to the original shipping costs being deducted from the refund.
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