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MASTER SPAS ML900 Topside (Replacement for the MAS560 Control Panel - X310801

MASTER SPAS ML900 Topside (Replacement for the MAS560 Control Panel - X310801

$376.99
$376.99 $368.70
SAVE -3% Sold out
MASTER SPAS ML900 Topside (Replacement for the MAS560 Control Panel - X310801

MASTER SPAS ML900 Topside (Replacement for the MAS560 Control Panel - X310801

$376.99
$376.99 $368.70
SAVE -3% Sold out

MASTER SPAS ML900 Topside (Replacement for the MAS560 Control Panel  - X310801

What our Experts Think
  • Critical system control component: The MS90U 825 3RD SENSOR control pack (X300739) is the core “brain” of compatible Master Spas systems, managing heating, pumps, and safety logic.
  • Advanced 3rd sensor monitoring: Includes enhanced sensor architecture for improved temperature accuracy, flow validation, and system protection—reducing overheating and dry-fire risks.
  • OEM-grade compatibility: Designed as a direct replacement for select Master Spas, ensuring proper integration with existing wiring, heater systems, and topside controls.
  • Stable spa performance: Experts value its role in restoring full spa functionality when units experience issues like error codes, inconsistent heating, or pump cycling failures.
  • Built for long-term durability: Engineered for continuous outdoor operation with sealed electronics and moisture-resistant housing for demanding spa environments.
  • Supports multi-function systems: Typically used in setups with multiple pumps and advanced filtration/heating configurations, maintaining synchronized system control.
  • Installation-sensitive part: Requires correct matching of sensors, configuration, and sometimes auxiliary boards—professional installation is strongly recommended for reliable performance.

Q&A

Q: What is the Master Spas MS90U 825 3rd Sensor Pack (X300739)?
A: The X300739 is a genuine OEM sensor pack designed for Master Spas control systems, specifically the MS90U 825 configuration, used to monitor water temperature and system performance.

Q: What does the 3rd sensor do?
A: The 3rd sensor provides additional temperature or system monitoring input to improve accuracy, safety control, and heater regulation in compatible spa systems.

Q: Is this an OEM replacement part?
A: Yes. The X300739 is an original Master Spas replacement sensor pack built for correct compatibility and reliable readings.

Q: What systems is it compatible with?
A: It is used in select Master Spas systems that require an MS90U 825 3-sensor configuration. Always verify your spa’s control system before ordering.

Q: What are common symptoms of a failing sensor?
A: Inaccurate temperature readings, heater issues, or error codes related to sensor imbalance may indicate the need for replacement.

Q: Is professional installation recommended?
A: Yes. Proper installation ensures correct sensor placement, sealing, and calibration within the spa control system.


Maintenance Tips
  • Keep spa water chemistry balanced (pH, alkalinity, sanitizer levels) to protect sensors and control pack components.
  • Clean or replace filters regularly to ensure proper flow across the MS90U 825 system and accurate sensor readings.
  • Inspect the 3rd sensor area for scale buildup or debris and clean with manufacturer-approved methods only.
  • Ensure all sensor connections remain dry, tight, and free from corrosion or moisture intrusion.
  • Monitor system for error codes or temperature fluctuations that may indicate sensor drift or failure.
  • Avoid using incompatible chemicals that can interfere with sensor accuracy or damage electronics.
  • Maintain proper water circulation to prevent stagnant zones that can affect readings.
  • Always disconnect power at the breaker before servicing or replacing any control pack components.
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