How to Replace an Old Whirlpool or Jacuzzi® Tub Heater (Even If It's Discontinued)

Don't Replace Your Whirlpool Tub—Replace the Heater

If your whirlpool tub heater has stopped working, you may think your entire bathtub has reached the end of its life. Fortunately, that's rarely the case.

Many older Whirlpool®, Jacuzzi®, Kohler®, American Standard®, MTI®, Jason®, Aqua Glass®, Hydro Systems®, Lasco®, Maax®, and other jetted bathtubs used inline water heaters that are now discontinued. The good news is that most of these heaters can be replaced with modern, safer, and more reliable alternatives.

At Whirly Bros, we've helped homeowners, plumbers, electricians, and service technicians replace thousands of obsolete whirlpool tub heaters without replacing the bathtub itself.

Why Whirlpool Tub Heaters Fail

A whirlpool tub heater is designed to maintain water temperature while your circulation pump is running. It is not intended to quickly heat cold bath water.

Over time, heaters can fail due to:

• Age
• Mineral buildup
• Corrosion
• Burned heating elements
• Failed pressure or flow switches
• Electrical damage
• Water intrusion
• Cracked housings

When this happens, many homeowners discover their original heater has been discontinued.

Don't worry—that doesn't mean your tub can't be repaired.

We Know Which Heater Replaces Your Old One

One of the biggest mistakes homeowners make is trying to match an old heater by appearance alone.

The correct replacement depends on several factors, including:

• Voltage (120V or 240V)
• Wattage
• Plumbing size
• Flow direction
• Pressure switch or vacuum switch operation
• Straight or Tee-style housing
• Plumbing layout
• Available installation space

This is where Whirly Bros stands apart.

We've spent years working with hydrotherapy systems from many of the industry's leading manufacturers, giving us the experience to recommend the correct replacement—even when the original part number has been discontinued.

Replacing Older Whirlpool & Jacuzzi® Heaters

Many tubs built during the 1990s and 2000s used heater systems that are no longer manufactured.

We regularly help customers replace obsolete heaters found in:

• Whirlpool® whirlpool tubs
• Jacuzzi® whirlpool bathtubs
• Kohler® whirlpool baths
• American Standard® walk-in tubs
• MTI® bathtubs
• Jason® Hydrotherapy systems
• Hydro Systems®
• Aqua Glass®
• Lasco®
• Maax®
• and many other hydrotherapy bathtub brands.

Even if your original heater looks completely different, there's often a modern replacement that performs the same function.

Not Every Heater Is the Same

One reason heater replacements can be confusing is that manufacturers used several different designs over the years.

Common differences include:

Straight Inline Heaters

Installed directly in the plumbing line with water flowing straight through the heater.

Tee-Style Heaters

Installed using a T-shaped plumbing configuration common on many whirlpool systems.

Pressure Switch Heaters

These heaters activate only when sufficient water flow is detected, protecting the heating element.

Vacuum Switch Heaters

Older systems may use vacuum-operated safety switches instead of pressure switches.

Choosing the wrong style can prevent the heater from operating correctly—or damage the system.

Signs Your Whirlpool Tub Heater Needs Replacement

Your heater may be failing if you notice:

• Water cools quickly during use
• Heater indicator light never comes on
• Heater trips the GFCI
• Visible corrosion
• Burn marks
• Water leaking from the heater body
• Cracked housing
• Error codes on electronic control systems

If you're unsure, we can often help diagnose the problem before you order parts.

Why Customers Choose Whirly Bros

Unlike large online retailers, we specialize in whirlpool bath repair.

We don't simply sell replacement parts—we help customers identify the correct solution.

Whether you're a homeowner tackling a DIY repair or a service technician working on multiple brands, our experience helps eliminate guesswork.

Our customers appreciate:

• Expert technical support
• Knowledge of discontinued systems
• Compatible replacement solutions
• Fast shipping
• High-quality components
• Friendly customer service

We Can Often Identify Your Heater From Photos

Don't know the part number?

No problem.

Simply send us:

• Photos of the heater
• Pump label
• Control box
• Plumbing layout
• Model information (if available)

Our team can often identify the correct replacement even if all labels have worn off.

Repair Your Tub—Don't Replace It

Replacing a whirlpool bathtub can cost several thousand dollars once demolition, plumbing, tile work, and installation are included.

In many cases, replacing the heater restores your tub for a fraction of that cost.

Can you replace a discontinued whirlpool tub heater?
Yes. Many discontinued whirlpool tub heaters can be replaced with modern inline heater systems that match the original voltage, plumbing size, and flow requirements.

How do I know which whirlpool tub heater I need?
The correct replacement depends on the tub's voltage, plumbing configuration, heater style, flow direction, and control system. Photos of the existing heater and pump are often enough for Whirly Bros to identify a compatible replacement.

Does a whirlpool tub heater heat cold water?
No. A whirlpool tub heater is designed to maintain the water temperature while the circulation pump is operating. It is not intended to quickly heat a tub filled with cold water.

Can I replace just the heater instead of the entire bathtub?
In most cases, yes. Replacing a failed inline heater is far less expensive than replacing the entire whirlpool tub and can restore normal operation.