Eliminating UFH Hot and Cold Spots: How Saswell SA905-T Ensures Uniform Heat Distribution

Dec 18,2025


"Tired of callbacks regarding uneven room temperatures? Discover how intelligent ΔT flow modulation ends the struggle of hydronic imbalance once and for all."




Introduction: The Invisible Enemy of Comfort


Underfloor heating (UFH) is marketed as the ultimate luxury, yet many homeowners suffer from hot and cold spots—where one room is freezing while another feels like a sauna. This isn't necessarily a boiler or pump issue; it is a hydronic imbalance problem. In this article, we’ll analyze why water fails to distribute heat evenly and how the Saswell SA905-T Stepper Motor Actuator provides the definitive solution through real-time ΔT balancing.


Saswell SA905-T stepper motor actuator for hydronic balancing to fix UFH hot and cold spots





Why Imbalance Occurs: The Physics of Resistance


Water always takes the path of least resistance. In a typical manifold system, heating loops vary in length, leading to unequal flow distribution:

Short Loops: Water flows through them too quickly, returning to the boiler before it can release its heat.

Long Loops: High pipe friction causes water to move too slowly, losing all energy before reaching the end of the circuit.

The Consequence: Short loops "starve" long loops of thermal energy, resulting in persistent hot and cold spots. (Read more: How Stepper Motors outperform Wax Actuators).





The ΔT Fix: Real-Time Flow Intelligence


Unlike "blind" ON/OFF actuators, the Saswell SA905-T utilizes an intelligent brain to monitor the Temperature Differential (ΔT) between flow and return pipes.

Throttling the Flow: If ΔT is too low, the stepper motor automatically throttles the valve to slow the water down, allowing it time to release heat.

Boosting the Flow: If ΔT is too high, the actuator opens further to increase circulation.

Dynamic Balancing: This continuous ΔT balancing technology ensures every room receives the exact heat required.


Thermal image comparison of UFH hot and cold spots






Smart Diagnostics: LED Indicators and Bluetooth App


The SA905-T eliminates the guesswork of traditional manual balancing:

LED Status Indicator: Integrated LEDs provide instant visual feedback on valve position and system health directly at the manifold.

E-Control App Integration: Via the Bluetooth App, engineers can monitor real-time temperatures and fine-tune parameters wirelessly. This makes the SA905-T a premier UFH retrofit solution for upgrading aging systems.


SA905-T actuator LED indicators and Bluetooth App diagnostic features





Conclusion: From Chaos to Consistent Comfort

Fixing UFH hot and cold spots doesn't require expensive re-piping; it requires intelligent control. By adopting the ΔT balancing logic of the Saswell SA905-T, you transform a chaotic system into a perfectly synchronized environment of uniform warmth.


👉 Ready to end the "cold spot" complaints? Contact us today for a detailed technical report.


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