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Thermodisc Hi-Limit Sensor HL9845 - Bubbles Supply

Thermodisc Hi-Limit Sensor HL9845

Part #: HL9845

$86.47
In stock — ships today
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1-year warrantySame-day ship before 3pm CTPerfect Fit Guarantee30-day returns

About this sensor

The HydroQuip Thermodisc Hi-Limit Sensor HL9845 is a surface-mount safety switch designed for HydroQuip spa control systems. This DPST (double-pole, single-throw) sensor protects your spa from dangerous overheating by automatically shutting down the heater when water temperatures exceed safe limits. The included mounting screws ensure secure installation on your spa's heater assembly or control box.

This OEM replacement sensor delivers exact fit guaranteed compatibility with HydroQuip systems, eliminating guesswork and ensuring reliable operation. Ships same-day from our Canadian warehouse and includes our comprehensive 1-year warranty for complete peace of mind. The HL9845 effectively resolves common spa error codes including HH (high heat), ICE (inadequate circulation), and OH (overheat) conditions. Verify your existing sensor's part number before ordering to ensure proper fitment with your specific HydroQuip control system.

Exact part number

HL9845

Save this for ordering or warranty claims

Also known as / Replaces

This part replaces or is interchangeable with:

  • DPST hi-limit
  • hi-limit switch
  • high limit thermodisc
  • overheat sensor
  • thermal cutout switch

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:

  • HH error code on spa display
  • OH (overheat) error code on spa display
  • ICE error code indicating inadequate circulation
  • Spa heater shuts off unexpectedly
  • Spa will not heat and displays a fault code
  • Control system locks out heater even when water temperature is normal

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

Before you buy — quick checklist

  • Confirm the part number on your existing thermodisc matches HL9845 before ordering
  • Verify your spa uses a HydroQuip control system — this is an OEM-specific part
  • Check whether your existing sensor is a DPST type — substituting incorrect switch configurations can cause control board faults
  • Inspect the heater manifold or control box mounting surface for corrosion or damage before installing
  • Confirm the error code you are seeing (HH, OH, ICE) is not caused by an underlying flow or circulation issue — replacing the sensor will not fix a failed pump or blocked filter

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

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

What's in the box

  • Thermodisc hi-limit sensor (HL9845)
  • Mounting screws

If your order is missing any items listed above, contact hello@bubblessupply.com within 48 hours of delivery.

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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