Swimables SW-41-178 MasterTemp Max-E-Therm Sensor

Key Fit

• Heater Drain Plug with O-Ring (SW-41-178) – Seals the drain port on compatible pool heaters to prevent leaks during operation

• Fits MasterTemp® & Max-E-Therm® Style Heaters – Designed for Pentair heater models that use this drain plug style (verify compatibility)

• Includes Matching O-Ring – Comes with the correct O-ring to ensure a tight, leak-free seal

• Critical for Freeze Protection – Commonly removed during winterization to allow heaters to fully drain

• Prevents Water Loss & Air Ingress – A properly sealed plug protects the heat exchanger and internal components

• Simple, Tool-Free Installation – Installs easily by hand for routine service and seasonal maintenance

• Replace When Worn or Leaking – Recommended if cracked, missing, or no longer sealing properly

The Swimables SW-41-178 Drain Plug with O-Ring is a replacement heater drain plug designed for Pentair MasterTemp and Max-E-Therm style pool heaters. This component is installed at the base of the heater to allow controlled draining of water from the heat exchanger during winterization, service, or equipment shutdown.

Drain plugs are a small but critical component of pool heaters. A missing, cracked, or poorly sealing plug can cause slow leaks, air intrusion, or water damage to surrounding equipment pads. The included O-ring ensures a tight, watertight seal when properly installed, helping protect the heater from leakage during normal operation.

This Swimables replacement is commonly used during heater service, seasonal winterization, or when replacing a lost or damaged original drain plug.

Why the Drain Plug Matters

Proper sealing at the heater base protects the entire system.

Why this matters:

• Prevents water leaks from the heater housing

• Protects the heat exchanger from air intrusion

• Allows safe draining during winterization

• Reduces risk of freeze damage

• Maintains proper heater operation

A worn or missing drain plug can lead to unnecessary heater damage and costly repairs.

Designed for MasterTemp & Max-E-Therm Style Heaters

The Swimables SW-41-178 drain plug is designed to match the form and function of MasterTemp and Max-E-Therm style heater drain ports. The included O-ring provides reliable sealing against heater threads when properly seated.

Using a heater-specific drain plug ensures correct fitment and helps avoid cross-threading or sealing issues that may occur with generic plugs. Always verify heater model compatibility before installation.

Easy Service and Winterization Replacement

Installing or removing the drain plug is a routine part of heater maintenance and winterization. The plug threads in easily and can be removed when draining the heater for freeze protection or internal service.

During installation, it is recommended to:

• Inspect threads for debris

• Ensure the O-ring is seated properly

• Hand-tighten to avoid over-compression

Replacing the drain plug during service is an inexpensive preventive step that helps protect heater components.

Product Specifications

Buy with Confidence from Benchmark Pool Supply

When you purchase the Swimables SW-41-178 Drain Plug with O-Ring from Benchmark Pool Supply, you’re choosing a service-ready replacement trusted by pool professionals. We stock dependable heater parts to help protect your equipment and extend service life.

Benchmark Pool Supply is your trusted source for pool heater parts and seasonal maintenance components.