The original ITT Marlow Gemini Plus R125A-C and 0010F00C whirlpool bath pumps are discontinued. This modern 1.25 HP, 120V replacement is designed for compatible single-speed, air-switch-controlled installations and operates at approximately 8.5 amps.
The replacement uses a modern motor and wet end selected to restore the strong water movement required by whirlpool bathtub jets. In many unmodified installations, the plumbing configuration closely follows the original layout. Pump unions and air-switch tubing are included to simplify installation.
Whirly Bros Compatibility Verified
This replacement has been selected for compatible ITT Marlow Gemini Plus R125A-C and 0010F00C whirlpool bathtub applications using 120V power, single-speed operation and a pneumatic air button.
Before ordering: Confirm the original pump label, voltage, control method, plumbing orientation, union connections, cord configuration and available installation space. Do not select a replacement using horsepower or amperage alone.
Not sure whether it fits? Send Whirly Bros clear photos of the original pump label, complete pump, plumbing connections and power cord. Call or text (951) 897-1878 for compatibility assistance before ordering.
What Replaces the R125A-C Pump?
This 1.25 HP replacement is the primary Whirly Bros solution for compatible ITT Marlow Gemini Plus R125A-C and legacy 0010F00C whirlpool bathtub installations.
The replacement provides:
- 1.25 HP single-speed operation
- 120V AC electrical configuration
- Approximately 8.5-amp operating current
- Factory-installed pneumatic air switch
- Strong water movement for whirlpool bath jets
- Modern motor and wet-end construction
- Pump unions and air-switch tubing
- One-year limited warranty
R125A-C Replacement Specifications
| Primary replacement |
ITT Marlow Gemini Plus R125A-C |
| Legacy identifier |
0010F00C |
| Application |
Indoor whirlpool and hydrotherapy bathtubs |
| Rated horsepower |
1.25 HP |
| Voltage |
120V AC |
| Frequency |
50/60 Hz |
| Operating current |
Approximately 8.5 amps |
| Operating speed |
Single speed |
| Control method |
Factory-installed pneumatic air switch |
| Power connection |
Factory-installed cord |
| Pump unions |
Included |
| Air-switch tubing |
Included |
| Condition |
Brand new |
| Warranty |
One year to the original purchaser |
Original R125A-C Compared with the Replacement
| Feature |
Original installation |
Current replacement |
| Availability |
Discontinued |
Brand new replacement |
| Primary identification |
R125A-C / 0010F00C |
Compatible replacement application |
| Power |
Verify original label |
120V, approximately 8.5A |
| Operation |
Single speed in compatible applications |
Single speed |
| Control |
Pneumatic air button |
Built-in pneumatic air switch |
| Plumbing |
Legacy Gemini Plus configuration |
Designed to preserve the layout in compatible, unmodified installations |
| Installation parts |
Existing components vary |
Pump unions and air tubing included |
Lower Electrical Draw Without Sacrificing Performance
Some older R125A-C-family installations used motors with a higher electrical draw. This replacement operates at approximately 8.5 amps and uses a modern motor and wet-end design selected to deliver the water movement needed by compatible whirlpool bathtub systems.
A lower amperage rating does not automatically mean weaker jet performance. Motor amperage is only one part of pump performance. Wet-end design, impeller configuration, plumbing resistance, jet count and the complete pump curve also affect water flow.
When the replacement is correctly matched to the original installation, it can reduce electrical demand while maintaining strong hydrotherapy performance. Exact results depend on the bathtub’s plumbing and jet configuration.
Will the Plumbing Connections Line Up?
This replacement is designed to preserve the original plumbing layout in many unmodified R125A-C and 0010F00C installations. The included unions help connect the replacement pump to the existing plumbing.
However, no replacement should be purchased based only on the model name. Previous repairs, altered PVC, different union styles and manufacturer-specific installations can affect alignment. Compare the suction position, discharge position and union connections with the product photographs before ordering.
Installation tip: Start the union nuts square and thread them by hand. The O-ring or gasket creates the watertight seal. Hand-tighten the unions evenly and do not apply Teflon tape or pipe compound to union threads that seal with an O-ring.
Compatible Pump Applications
The R125A-C and 0010F00C are the primary applications for this replacement. Based on complete system compatibility, this same replacement configuration may also be used in select:
- ITT Marlow Gemini Plus R75A-C installations
- ITT Marlow Gemini Plus R100A-C installations
- ITT Marlow Gemini Plus R125A-C installations
- ITT Marlow Gemini Plus R150A-C installations
This does not mean every R75A-C, R100A-C, R125A-C or R150A-C pump is automatically interchangeable. Different part numbers, horsepower ratings and amperage ratings do not determine compatibility by themselves.
Compatibility requires matching:
- 120V electrical supply
- Single-speed operation
- Pneumatic air-button control
- Suction and discharge orientation
- Plumbing connection size and style
- Power cord and receptacle configuration
- Available installation clearance
- Any previous plumbing or electrical modifications
What Is Included?
- One new 1.25 HP whirlpool bathtub pump
- Factory-installed pneumatic air switch
- Factory-installed power cord
- Pump union fittings
- Air-switch tubing
- One-year limited warranty
Additional PVC fittings, electrical modifications, mounting hardware and other installation materials are not included unless specifically shown or selected separately.
How the Air Switch Works
The pump is operated by a pneumatic air button mounted on the bathtub. Pressing the button sends a pulse of air through the small tube to the switch inside the pump’s electrical enclosure. One press turns the pump on, and the next press turns it off.
A damaged air button, disconnected tube, split tube or kinked air line can prevent the pump from responding. These components should be inspected before assuming that the motor has failed.
Common Signs the Original Pump Needs Replacement
- The motor hums but does not start
- The pump does not respond to the air button
- Water leaks from the shaft-seal area
- The motor produces loud bearing or grinding noises
- The pump overheats or shuts down
- The GFCI trips when the pump starts
- The wet end is cracked or damaged
- Jet pressure has become noticeably weaker
- The pump produces excessive vibration
A no-start condition can also be caused by the GFCI outlet, power cord, air button, air-switch tubing or internal air switch. Verify these components before replacing the pump.
Before Ordering: Compatibility Checklist
- Photograph the complete original pump before removing it.
- Photograph the motor and pump identification labels.
- Confirm that the system operates on 115–120V.
- Confirm that the original system is single speed.
- Confirm that the bathtub uses a pneumatic air button.
- Compare the suction and discharge positions.
- Compare the original union connections with the product photographs.
- Check the power cord and receptacle.
- Measure the available installation space.
- Look for previous plumbing or electrical modifications.
Important Installation Notes
- Turn off and disconnect electrical power before accessing the pump.
- Confirm the replacement specifications against the original label.
- Photograph the original plumbing, cord and air-tube arrangement.
- Remove the original pump and inspect the plumbing for damage.
- Install the supplied unions while maintaining proper alignment.
- Use the correct union seals or O-rings.
- Hand-tighten the union connections evenly.
- Connect the bathtub’s air button to the built-in air switch.
- Secure the pump on a stable and level mounting surface.
- Connect it only to a properly grounded and GFCI-protected 120V receptacle.
- Fill the bathtub above the highest jet before operating the pump.
- Check all plumbing connections for leaks.
Never run a whirlpool pump without water in the bathtub. Dry operation can damage the mechanical seal and cause the new pump to leak.
Professional installation is recommended when electrical access, plumbing alignment or compatibility is uncertain.
Frequently Asked Questions
Is the original R125A-C discontinued?
Yes. The original ITT Marlow Gemini Plus R125A-C is discontinued. This product is a modern aftermarket replacement for compatible R125A-C installations.
Does this replace legacy part number 0010F00C?
Yes. The 0010F00C is a primary legacy identifier covered by this replacement. The original voltage, control method, plumbing arrangement and available space should still be confirmed.
Is this an original ITT Marlow pump?
No. The original ITT Marlow pump is no longer manufactured. This is a new aftermarket replacement selected for compatible ITT Marlow Gemini Plus applications.
Does lower amperage mean less water flow?
Not necessarily. Amperage alone does not determine pump output. The motor, impeller, wet-end design, plumbing resistance and jet configuration all affect performance. This replacement is designed to maintain strong whirlpool water movement while operating at approximately 8.5 amps.
Will the unions line up without replumbing?
They are designed to align in many compatible, unmodified R125A-C and 0010F00C installations. Previous repairs or altered plumbing can affect alignment, so the complete installation should be compared with the product photographs.
Are unions included?
Yes. Pump union fittings are included.
Is air-switch tubing included?
Yes. Air-switch tubing is included with the replacement package.
Does the pump have a built-in air switch?
Yes. A pneumatic air switch is factory installed.
Is this a variable-speed pump?
No. This product is configured as a single-speed pump operated by a pneumatic air button. Variable-speed systems require a compatible electronic control system and should not be replaced solely with this air-switch configuration.
Can it replace R75A-C, R100A-C or R150A-C?
It may replace select compatible installations when voltage, control method, plumbing orientation, union connections, cord configuration and available space match. Do not substitute pumps based only on model name, horsepower or amperage.
Can this be used in a portable hot tub?
No. This product is intended for compatible indoor whirlpool and hydrotherapy bathtubs. It is not intended for portable spas, swimming pools or continuous-circulation hot-tub systems.
What warranty is included?
The replacement includes a one-year limited warranty for the original purchaser. Retain the Whirly Bros receipt as proof of purchase.
Can Whirly Bros confirm compatibility?
Yes. Send photos of the original pump label, complete pump, plumbing, power cord and air-switch tubing. Call or text (951) 897-1878 or email whirlybros@gmail.com.
Why Buy from Whirly Bros?
Whirly Bros specializes in difficult-to-find whirlpool bathtub pumps, controls, blowers and retrofit systems. We help homeowners, plumbers, contractors and maintenance professionals identify replacements for discontinued bath equipment.
- Hands-on knowledge of legacy ITT Marlow and Gemini Plus systems
- Compatibility assistance before and after the sale
- Detailed electrical, plumbing and control information
- Same-business-day shipping on qualifying in-stock orders
- Free U.S. shipping on orders over $100
- One-year limited warranty
- Phone and text support at (951) 897-1878
Whirly Bros Expert Tip: Do not rely only on the horsepower printed on the old pump. Pumps with different ratings may use similar housings, while pumps with similar ratings may have different controls or plumbing. The complete configuration determines compatibility.
Read the complete R125A-C identification and replacement guide →
Need help identifying your pump? Call or text Whirly Bros at (951) 897-1878 and send us photos before ordering.
ITT, Marlow, Gemini Plus and all referenced manufacturer names and part numbers are used solely for identification and compatibility purposes. Whirly Bros is an independent replacement-parts supplier and is not affiliated with, endorsed by or sponsored by the referenced trademark owners. This product is an independently manufactured aftermarket replacement and is not an original ITT Marlow product. Compatibility depends on the original pump’s electrical rating, control method, plumbing configuration, mounting arrangement, cord configuration and available installation space.
