Excellent 4.9 | 18,452 reviews

MASTER SPAS Heater 4kW - X300937

MASTER SPAS Heater 4kW - X300937

$250.99
$250.99 $333.50
SAVE 24% Sold out
MASTER SPAS Heater 4kW - X300937

MASTER SPAS Heater 4kW - X300937

$250.99
$250.99 $333.50
SAVE 24% Sold out

MASTER SPAS Heater 4kW  - X300937

Heater 4 kW with M7 sensors(V/N 55950)

What our Experts Think
  • Reliable OEM Heating Replacement – The X300937 is a genuine 4kW Master Spas heater assembly designed to restore proper heating performance in compatible swim spas and hot tubs.
  • Stable, Efficient Heat Output – 4kW (240V) configuration delivers balanced heating for consistent water temperature maintenance without overloading the spa system.
  • Engineered for M7 Systems – Built for Master Spas setups using M7 sensor technology, ensuring accurate temperature control and safe operation.
  • Direct Drop-In Replacement – Designed to match original fit and plumbing layout, helping reduce installation time and avoid system modifications.
  • Supports Multiple Master Spa Lines – Commonly used in select H2X Swim Spa and Momentum configurations, making it a widely trusted service part.
  • Service-Critical Component – Ideal replacement when symptoms include no heat, inconsistent temperature rise, or heater failure due to internal element or sensor faults.

Q&A

Q: What is the MASTER SPAS 4kW Heater (X300937)?
A: A genuine OEM 4.0kW flow-through electric heater used in Master Spas systems to heat and maintain water temperature in swim spas and hot tubs.

Q: What does it do?
A: It heats circulating spa water as part of the control system, working with sensors and the spa pack to maintain set temperature and prevent overheating or dry-fire conditions.

Q: What spas is it compatible with?
A: Commonly used in select Master Spas swim spas (including H2X Momentum systems) and models using the M7 control platform.

Q: What are its specifications?
A: 4.0kW power rating, 240V operation, stainless steel flow-through design with integrated temperature sensors for system protection.

Q: Is it a direct replacement part?
A: Yes, it replaces original heater assemblies in compatible Master Spas systems and is designed for direct OEM fitment.

Q: Does it require professional installation?
A: Yes. Correct wiring, sensor connection, and system configuration are required to avoid damage and ensure safe operation.


Maintenance Tips
  • Maintain balanced water chemistry (pH, alkalinity, calcium hardness) to prevent scale buildup and corrosion inside the heater.
  • Clean or replace filters regularly to ensure proper water flow and avoid heater overheating or lockout.
  • Ensure consistent water circulation; never operate the heater with low or no flow conditions.
  • Inspect unions and fittings for leaks or drips that could damage electrical components.
  • Monitor for error codes or slow heating, which may indicate scaling or flow restriction.
  • Periodically check for calcium buildup and descale the heater as needed using approved methods.
  • Keep the equipment bay dry and well-ventilated to prevent moisture-related electrical damage.
  • Always turn off power at the breaker before servicing or replacing the heater.
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