Solar System Freeze Protection

Solar Thermal System Protection & Control: Intelligent Freeze Prevention and Temperature Regulation Solutions

Engineered specifically for solar thermal systems to eliminate freeze-cracking risks and ensure uninterrupted operation.

The Challenge & Solution

Solar thermal systems face two critical operational challenges: catastrophic freeze damage in winter and temperature instability due to fluctuating solar irradiance. Traditional electrical solutions add complexity and failure points.

Our integrated valve solution provides a purely mechanical, reliable answer:

1. Freeze Protection (FP15GD, FP65): Automatically drains minimal water to prevent pipe bursting when temperatures drop.
2. Temperature Balancing (MD Series): Precisely mixes or diverts flow to maintain constant outlet temperatures, maximizing system efficiency.

No external power required. No complex controllers. Just reliable, self-regulating protection.

Freeze Protection Series

Product Overview

The FP15GD and FP65 Freeze Protection Valves are self-contained, thermostatically operated safety valves designed specifically for solar collector loops. Utilizing a highly sensitive wax thermal actuator placed directly in the fluid stream, these valves modulate open only when the fluid temperature approaches freezing, discharging the minimum amount of water necessary to prevent ice formation.

Applications & Selection

Model	Opening/Closing Temp Range	Ideal Application Scenario	Technical Benefit
FP15GD-35 / FP65-35	1°C (Open) / 4°C (Close)	Water Tube	Narrow temperature band protects sensitive water tubes without unnecessary water loss.
FP15GD-45 / FP65-45	3°C (Open) / 6°C (Close)	Flat Panel Collectors	Slightly higher trigger point accounts for the larger water volume and heat capacity of flat panels.

• System Compatibility: Suitable for both Thermo-siphoning Systems and Pump Circulation Systems.
• Installation Logic: Installed at the lowest point or critical exposure zone where warmer supply water passes through collectors first, ensuring the valve senses the coldest potential fluid temperature.

Key Benefits

• Zero Energy Dependency: Operates entirely on thermal expansion principles; no electricity or air pressure needed.
• Minimal Water Loss: Discharges only the precise amount of water required to prevent freezing, then reseals tightly as temperatures rise.
• Ambient Immunity: The actuator is immersed in the fluid, making it unaffected by wind chill or ambient air temperature fluctuations.
• Fast Response: Compact, low-mass design ensures rapid reaction to sudden temperature drops.
• Robust Construction: Brass body and ram-type plug ensure reliable tight shutoff and durability against pressure variations.

Temperature Control Series

Product Overview

The MD Series 3-Way Mixing/Diverting Valves are precision temperature control devices designed to balance solar thermal output. Whether configured for mixing (blending hot/cold flows) or diverting (switching flow paths), these valves automatically adjust port positions based on fluid temperature to maintain a stable setpoint.

Applications & System Logic

• Scenario A: Solar Pre-heat Balancing (Mixing Application)
  • Context: Solar tank output varies throughout the day.
  • Function: Proportions flow from the hot solar loop and cold makeup water to deliver a consistent, safe temperature to the usage point or storage tank.
  • Benefit: Prevents scalding and stabilizes downstream processes.
• Scenario B: Multi-Collector Flow Balancing (Diverting/Mixing)
  • Context: Different collectors receive uneven solar exposure (shade, orientation).
  • Function: Automatically restricts flow to overheated collectors and increases flow to cooler ones, or diverts low-temp water back for reheating.
  • Benefit: Maximizes total system efficiency by equalizing thermal output across the array.
• Scenario C: Auxiliary Heating Integration
  • Context: Solar pre-heated water < 45°C.
  • Function: Diverts flow to an auxiliary boiler/heater. When > 45°C, diverts directly to the mixing stage.
  • Benefit: Seamless integration of solar and backup energy sources.

Key Benefits

• Self-Regulating Precision: Maintains setpoint temperatures within a narrow tolerance (±2°C) without external sensors or controllers.
• Versatile Configuration: Can be used for both Mixing (2 inlets, 1 outlet) and Diverting (1 inlet, 2 outlets) applications.
• Wide Operating Range: Effective from 20°C up to high-temperature solar limits (consult specific model specs).
• Material Durability: Available in Brass housings, resistant to corrosion in hydronic loops.
• OEM Flexibility: Adjustable and pre-calibrated models available; Optional built-in check valve.

Why Choose Our Solar Solution?

• Reliability in Extreme Climates: Proven performance in sub-zero conditions where electronic sensors often fail.
• Total System Protection: From freeze-burst prevention (FP Series) to over-temperature regulation (MD Series), we cover the entire thermal safety spectrum.
• Low Maintenance: No moving parts to wear out quickly, no batteries to replace, no software to update. Install and forget.
• Cost-Efficiency: Reduces water waste, prevents costly pipe replacements, and optimizes energy harvest from solar collectors.
• Global Compliance: Designed to meet international standards for plumbing and solar thermal applications.

Technical Specifications Snapshot

Feature	FP15GD (Freeze Protection)	FP65 (Freeze Protection)	MD Series (Temp Control)
Operation Type	Normally Closed (Opens on Freeze)	Normally Closed (Opens on Freeze)	Mixing / Diverting
Actuation	Self-contained Thermal Element	Self-contained Thermal Element	Self-contained Thermal Element
Power Source	None (Mechanical)	None (Mechanical)	None (Mechanical)
Body Material	Brass	Brass	Brass
Port Sizes	NPT 1/2″	NPT Male 3/4″	DN15, DN20
Set up Temp.	1°C – 4°C, 3°C – 6°C	1°C – 4°C, 3°C – 6°C	37°C, 45°C, Other customizable temperatures
Response Time	Fast	Fast	Fast
Pressure Rating	Standard Solar System Pressure	Standard Solar System Pressure	Standard Hydraulic Pressure