Propylene Glycol Heat Transfer Fluid for Heating Systems and Boilers FREEZLIGHT −32 °C

Propylene Glycol Heat Transfer Fluid for Heating Systems and Boilers FREEZLIGHT® −32 °C

Short Description

FREEZLIGHT® −32 °C is a ready-to-use propylene glycol USP heat transfer fluid for heating systems, underfloor heating, combi boilers, heat pumps, solar thermal collectors and refrigeration equipment. It contains a carboxylate functional additive package, is covered by a state sanitary and epidemiological expert conclusion, and protects the system against freezing, corrosion and deposit formation. The FREEZLIGHT® product line has been manufactured since 2010 and, with correct system preparation and operation, provides a service life of more than 5 years.

Key Specifications

What FREEZLIGHT® −32 °C Is and What It Is Used For

FREEZLIGHT® −32 °C is a ready-to-use, non-freezing propylene glycol USP fluid for heating, cooling and heat transfer circuits that may be exposed to temperatures below 0 °C. It transfers thermal energy, protects equipment from freeze damage and creates a corrosion-inhibited environment inside the system.
The formulation contains propylene glycol, demineralised water and a carboxylate functional additive package. Corrosion inhibitors protect ferrous and non-ferrous metals, stabilising components reduce deposit formation, and antifoam additives control foaming during filling and circulation.
The product also contains a special fluorescent tracer that assists professional leak detection.
FREEZLIGHT® heat transfer fluids have been manufactured since 2010. The formulation has been refined on the basis of practical operation in private houses, administrative and industrial buildings, heat pump systems and solar thermal collector circuits.

Intended Use

The fluid is used to protect systems against freezing during emergency or seasonal shutdowns, transfer thermal energy, reduce corrosion of metal components and limit deposit formation.
Propylene glycol has significantly lower toxicity than ethylene glycol. The product is covered by a state sanitary and epidemiological expert conclusion and may be used at food-industry facilities within the scope specified in that conclusion.

Applications

• radiator heating systems
• hydronic underfloor heating systems
• gas, electric, solid-fuel and pellet boilers
• combi boilers, subject to equipment manufacturer requirements
• heat pumps
• solar thermal collectors and other solar thermal systems
• heat recovery systems
• refrigeration equipment
• process cooling systems
• industrial heat exchangers and closed-loop heat transfer circuits

This fluid must not be used in electrode boilers unless the boiler manufacturer explicitly permits it. Electrical conductivity is part of the operating principle of this equipment, so the required fluid composition is specified by the boiler manufacturer.
FREEZLIGHT® −32 °C is compatible with most modern heating systems, provided the technical requirements of the boiler, pump, heat exchanger and sealing-material manufacturers are followed.
Practical note from Novohim. Fluid selection must not be based on crystallisation temperature alone. Maximum circuit temperature, operating pressure, system materials and equipment manufacturer requirements must also be considered.

Compatible Materials

• carbon steel and stainless steel
• cast iron
• copper
• brass and bronze
• aluminium alloys
• polypropylene, PEX, PE-RT and multilayer composite pipes
• rubber and polymer seals designed for water-glycol solutions

Before filling, verify compatibility with the specific equipment and sealing materials using the manufacturers’ technical documentation.

How the Heat Transfer Fluid Works in Boilers and Solar Thermal Systems

During circulation, the fluid absorbs heat in the boiler, heat pump, solar thermal collector or another heat source and transfers it to radiators, underfloor heating loops or heat exchangers. At the same time, carboxylate inhibitors limit corrosion processes on metal surfaces.
Unlike water, the fluid performs two functions: heat transfer and freeze protection. However, a water-propylene glycol mixture has lower specific heat capacity and thermal conductivity and higher viscosity than water. Pump capacity, hydraulic resistance and heat exchange area must therefore be considered when designing a system or converting an existing water-filled system to glycol.

What the −32 °C Initial Crystallisation Temperature Means

The −32 °C rating indicates the initial crystallisation temperature, not immediate complete solidification. As cooling continues, separate ice crystals begin to form and the remaining liquid phase becomes richer in propylene glycol.
The fluid gradually develops a thick, crystalline consistency without the abrupt volumetric expansion associated with freezing water. This reduces the risk of damage to pipes, radiators, pumps and heat exchangers. When the temperature rises, the fluid regains flowability, provided it has not been exposed to prolonged overheating or severe contamination.
Practical note from Novohim. The initial crystallisation temperature depends on propylene glycol concentration. Adding water raises this temperature; after a major top-up, concentration should be checked with a refractometer.

What Determines the Boiling Temperature

Boiling temperature depends on both fluid composition and system pressure. At atmospheric pressure it is lower than in a sealed circuit operating under positive pressure. This is why heating-system and solar-thermal documentation may state different upper temperature limits.
In solar thermal systems, higher pressure increases the boiling temperature, but it does not provide unlimited thermal stability. Prolonged overheating accelerates propylene glycol degradation and additive depletion. The maximum operating regime must be determined from the equipment data sheet, operating pressure and collector stagnation temperature.
Practical note from Novohim. Boiling temperature and permissible continuous operating temperature are not the same parameter. A fluid may not yet be boiling while already ageing rapidly due to overheating.

Why Propylene Glycol Is Selected

The FREEZLIGHT® range includes propylene glycol-, ethylene glycol- and glycerine-based heat transfer fluids. Selection depends on toxicological properties, cost, viscosity and system design.

Main Properties and Advantages

1. USP-grade propylene glycol base fluid
2. initial crystallisation temperature of −32 °C
3. carboxylate corrosion inhibitor technology
4. protection of ferrous and non-ferrous metals
5. reduced scale and deposit formation
6. fluorescent tracer for professional leak diagnostics
7. state sanitary and epidemiological expert conclusion
8. manufactured in Ukraine under the FREEZLIGHT® brand since 2010
9. service life of more than 5 years with correct system preparation and operation

Practical Operating Experience

Operational experience shows that service life depends not only on fluid quality. System cleanliness, leak tightness, temperature regime, air content and the frequency of water top-up all affect fluid condition.
Repeated addition of fresh water introduces oxygen and hardness salts, changes propylene glycol concentration and accelerates depletion of the protective additive package. If frequent top-up is required, the leak must be found and repaired first.
The fluorescent tracer assists professional detection of microleaks. In domestic conditions, very small leaks can also be located with chalk: rub chalk onto the fingers and check threaded joints, valves and other likely leak points. Moisture marks are easier to see on the chalk.

System Preparation Before Filling

Check system leak tightness before filling. Fill the circuit with water, install a pressure gauge and apply the test pressure specified by the system design and equipment manufacturer. After the holding period, monitor the gauge and inspect threaded joints, pumps, shut-off valves, safety groups, automatic air vents, heat exchangers and expansion vessels.
Glycol fluid has a higher viscosity than water, but in practice it is also more demanding of seal quality. Connections that remained dry with water may begin to weep after conversion to a water-glycol solution. Threaded joints should be assembled using suitable seals or plumbing flax together with a compatible sealing paste.
A system that has operated for a long time with water or old heat transfer fluid should be flushed if sediment, rust or other contamination is present. After hydrostatic testing, drain the water as completely as possible because residual water reduces the concentration of ready-to-use fluid and raises the initial crystallisation temperature.
Detailed guidance is provided in the article “Recommendations for Replacing Heat Transfer Fluid and Maintaining the Heating System”.

Recommendations for Use

• do not mix with unknown fluids or products from other manufacturers without prior compatibility testing
• use the same fluid for top-up; add water only after accounting for the resulting change in crystallisation temperature
• demineralised water is preferred for dilution; potable tap water may be used in domestic systems if it is not excessively hard and contains no sediment or mechanical contamination
• after filling, remove air from the circuits and recheck pressure after the first heat-up and cool-down cycle
• avoid prolonged operation above temperatures specified by the system design and equipment manufacturer
• assess fluid condition not only by colour but also by concentration, clarity, sediment and odour changes

Why Automotive Antifreeze Should Not Be Used

Automotive antifreeze is formulated for internal-combustion-engine cooling systems, which involve different materials, thermal cycles and additive requirements. In heating systems it may create undesirable operating risks, and many automotive coolants are based on toxic ethylene glycol.
Stationary heating systems require a specialised heat transfer fluid with an additive package designed for long-term circulation through boilers, radiators, underfloor heating loops and heat exchangers.

Application Limitations

• use in electrode boilers only with explicit approval from the equipment manufacturer
• do not mix with fluids of unknown composition
• check system leak tightness and technical condition before use
• if the system requires repeated water top-up, locate and eliminate the leak first
• do not exceed the temperature and pressure limits specified by the equipment manufacturer
• use only in circuits whose materials have confirmed compatibility with water-propylene glycol solutions

Safety Precautions

The lower toxicity of propylene glycol fluid compared with ethylene glycol formulations does not eliminate the need for safe handling. Wear protective gloves and eye protection. In case of skin or eye contact, rinse thoroughly with water. Do not reuse empty containers for drinking water or food products. Keep out of reach of children and animals.

Storage

Store in the original tightly closed container, under cover and protected from precipitation, direct sunlight and heat sources. Prevent contamination. After prolonged storage, mix the contents before use.

Conclusion

FREEZLIGHT® −32 °C is a ready-to-use propylene glycol heat transfer fluid for systems requiring freeze protection, corrosion inhibition and an improved toxicological profile. It is used in heating systems, underfloor heating, heat pumps, solar thermal systems and process equipment in accordance with the equipment manufacturer’s requirements.
A service life exceeding 5 years is achieved with a clean, leak-tight system, correct temperature control, no repeated water top-up and periodic monitoring of the fluid condition.

FAQ

Can FREEZLIGHT® −32 °C be used in a combi boiler?

Yes, subject to approval by the boiler manufacturer. Propylene glycol is significantly less toxic than ethylene glycol, but any transfer-fluid ingress into the potable-water circuit remains unacceptable.

Is it suitable for underfloor heating?

Yes. When converting from water, account for the higher viscosity of the water-propylene glycol solution and verify sufficient circulation in long loops.

Can it be used in an electrode boiler?

Not without explicit approval from the electrode-boiler manufacturer. This equipment relies on a specified electrical conductivity of the fluid.

Can FREEZLIGHT® be mixed with another heat transfer fluid?

Not without compatibility testing. Different additive packages may interact, form deposits or lose protective performance.

Can water be added?

Only with the understanding that water lowers propylene glycol concentration and raises the initial crystallisation temperature. After a substantial top-up, verify concentration with a refractometer.

What water should be used for dilution?

Demineralised water is preferred. Potable tap water may be used in domestic systems if it is not excessively hard and contains no sediment or mechanical contamination.

Why did leaks appear after replacing water?

Water-glycol solutions are more demanding of seal quality. Pressure-test the system with a gauge before filling and repair all leaks.

What does −32 °C mean?

It is the initial crystallisation temperature, not immediate complete freezing. As cooling continues, the fluid gradually thickens as crystals form.

Why are higher temperatures stated for solar thermal collectors?

Higher pressure in a sealed solar thermal circuit increases boiling temperature. However, the permissible continuous temperature is determined by the equipment data sheet because overheating accelerates fluid degradation.

How can a small leak be found?

Professionally, by using the fluorescent tracer and diagnostic equipment. In domestic systems, suspected leak points can also be checked with chalk because moisture marks are easy to see.

When should the fluid be replaced?

Under proper conditions, service life exceeds 5 years. Replace earlier if severe contamination, sediment, significant odour change, loss of concentration or additive depletion is observed.

How is it different from automotive antifreeze?

Its additive package is designed for long-term operation in stationary heating and heat transfer systems. Automotive coolants are intended for different duty conditions and often contain toxic ethylene glycol.

Go to the link and choose your Heat transfer fluid (HTF):

propylene glycol-based

based on glycerin

based on ethylene glycol

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