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18" Hi-Limit Sensor 34-0201D - Bubbles Supply

18" Hi-Limit Sensor 34-0201D

Part #: 34-0201D

$55.57
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1-year warrantySame-day ship before 3pm CTPerfect Fit Guarantee30-day returns

About this sensor

The HydroQuip 18" Hi-Limit Sensor (34-0201D) is a critical safety component designed for HydroQuip control systems in hot tubs and spas. This OEM replacement sensor features an 18-inch cable length with a 1/4" bulb diameter and 2-wire configuration, providing reliable overheat protection by automatically shutting down your spa when water temperatures exceed safe limits.

Built to HydroQuip's exact specifications, this genuine replacement part ensures your spa's safety systems function properly. At Bubbles Supply, we guarantee an exact fit for your control pack, backed by our 1-year warranty and same-day shipping on in-stock items. The sensor's durable construction and precise calibration make it essential for maintaining safe spa operation. Professional installation is recommended to ensure proper sensor placement and secure electrical connections within your spa's control system.

Exact part number

34-0201D

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Also known as / Replaces

This part replaces or is interchangeable with:

  • Hi-limit sensor
  • high-limit sensor
  • overheat sensor
  • spa safety sensor
  • thermal cutoff sensor

Looking for an older part number? Check our supersession lookup tool

Common symptoms this part fixes

If your spa is showing any of these signs, this part is likely your fix:

  • Spa shuts off immediately after startup
  • Spa won't heat and displays hi-limit fault or error code
  • Control pack trips repeatedly with no apparent overheating
  • Spa runs cold — hi-limit sensor failed open and control pack reads false overheat
  • Intermittent nuisance shutdowns during normal operation
  • Spa locked out and unresponsive after temperature spike

Not sure if this is your problem? Try our diagnostic centre or .

Before you buy — quick checklist

  • Confirm your control pack is a HydroQuip unit and verify the exact control pack model number before ordering
  • Locate the existing sensor and measure the cable length — confirm 18 inches is sufficient to reach the sensor well from the control pack
  • Check the sensor well or thermowell diameter to confirm compatibility with the 1/4" bulb
  • Verify you are replacing the hi-limit sensor and not the temperature sensor — these are separate components and often look identical
  • Inspect the sensor well for corrosion or debris that may have caused the original failure before installing the new sensor

Reading the checklist now prevents 90% of returns. Worth the 60 seconds.

Install difficulty: Medium — Some experience neededTypically 30-60 minutes

Warranty

1 year manufacturer warranty against defects

Covers manufacturing defects. Does not cover improper installation, normal wear, or accidental damage.

Warranty claims: warranty@bubblessupply.com

Perfect Fit Guarantee

Ordered with our help and the part doesn't fit? Contact us before installation. We'll resolve it with an exchange, replacement recommendation, or return approval.

Learn about our Perfect Fit Guarantee →

Shipping

We ship across the US and Canada. US orders ship from our US warehouse to US customers; Canadian orders ship from our Canadian warehouse to Canadian customers — no cross-border shipping, no surprise duties. In-stock orders placed before 3pm CT ship same day. Standard shipping $9.95 flat rate. Free shipping on orders over $200. Express options available at checkout.

Returns

30-day hassle-free returns on unused parts in original packaging. Contact us before returning to receive your RMA number.

Frequently asked questions

Check the Compatibility section above to confirm fitment for your spa brand and model. If your model is not listed, use our fitment selector at /pages/find-my-part or ask our parts AI for a personalized recommendation.

In-stock orders placed before 3pm CT ship the same day. You will receive tracking information by email as soon as your order ships.

We accept returns within 30 days of delivery for unused items in original packaging. Email returns@bubblessupply.com with your order number to start a return. Installed electrical parts cannot be returned for safety reasons.

Yes, all new parts come with a 1-year warranty against manufacturing defects. Warranty does not cover damage from improper installation or normal wear and tear.

Customer reviews

AI Fitment Assistant

Tell us your spa model and we will confirm this part fits before you buy.

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