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Frequently Asked Questions

Have More Questions?  Contact UsOur knowledgeable engineers and technical support team are available to provide expert product support and consultation. 

FAQ Answers

1 - Can I use bare mineral oil instead of buying engineered heat transfer fluids?

Caldera Heat Transfer fluids are specifically formulated to mitigate thermal and oxidative degradation. 

When compared to normal mineral oils, there will be reduced sludge and varnish formation, reulsting in a reduction in maintenance costs increased fluid life. The overall cost of using bare mineral oil is a lot higher when compared to a fully additized heat transfer fluid like Caldera.

2 - What is the maximum and minimum temperature for Caldera Heat Transfer Fluids?

Caldera Heat Transfer Fluids cover a broad temperature range ( -120 °F to 640 °F). We are also able to supply synthetic fluids that can handle temperatures up to 750 °F.

3 - Is Caldera Heat Transfer Fluid compatible with my mineral oil-based heat transfer fluid?

Caldera Heat Transfer Fluids are top-off compatible with most mineral oil-based heat transfer fluids.

4 - I have varnish and sludge buildup in my heat transfer system. What do I do?

There are two options to consider:

For systems needing immediate solutions, depending on the amount of fouling deposition, apply a 5-10% treat of our concentrated Caldera Rescue HTF cleaner to your existing heat transfer fluid. Caldera Rescue HTF is formulated to eliminate varnishes and dissolve sludge without taking the system offline.

The second option may be to replace entire system volume with a fill of Caldera 16, a mineral oil-based heat transfer fluid that contains a cleaner. The inherent cleaning additive in the fluid dissolves varnishes and restores heat transfer efficiency back to design values. Caldera 16  is effective where the deposition is not extensive and only a varnish layer has formed on the heat transfer surface. If you already have insoluble solids/sludge in the system, it is advisable to use Rescue Cleaner before introducing new heat transfer fluid.

Sludge formation is an indication of advanced fluid oxidation. It is very important to discuss options to mitigate this with your heat transfer fluid manufacturer. Isel engineers and representatives can advise on best practices to avoid fluid degradation. 

5 - How is Caldera different from other heat transfer fluids I have used in the past?

Caldera Heat Transfer Fluids contain a complex combination of primary and secondary anti-oxidants. These give Caldera Heat Transfer Fluids longer fluid life by mitigating the oxidation reaction that occurs when a fluid comes in contact with oxygen and other contaminants. This is in contrast with many heat transfer fluids on the market that contain only a slight additive/stabilizer treat. Those fluids will oxidize quicker, increase facility downtime and system maintenance costs.

Caldera Heat Transfer Fluids are also formulated from very thermally stable base stocks. Caldera Heat Transfer Fluids contain no contaminants. As such, there is no tendency to internally catalyze adverse reactions.

6 - I suspect there may be water in my heat transfer system, how do I deal with that?

You can send Isel a fluid sample so that we can test for moisture content.

Moisture can enter into a fluid system due to improper seals, hydrotesting with water, improper handling and other system leaks. Preliminary warning signs of water in the system include a low discharge pump pressure and pump cavitation.

Water can cause a variety of problems in a heat transfer system. For instance:

  • Water entrained in heat transfer systems operated below 0°C can form ice crystals that may clog valves and form a coating on heat exchanger surfaces
  • In high-temperature applications, any moisture could turn to steam, which may increase internal pressure resulting in an eruption
  • It increases oxidation, the chemical reaction between a fluid and oxygen that shortens the fluid’s service life
  • It promotes rust and corrosion of metal parts, resulting in greater maintenance costs and downtime
  • It can interfere with the proper function of fluid’s additives, thereby adversely affecting fluid performance

One way to get rid of the moisture content in your heat transfer system is to boil off the water as steam through vents on your expansion tank. Some of our customers also use a desiccation system that dries out the moisture.

7 - How can I prevent water from getting into my system?

In addition to choosing a high quality heat transfer fluid, these steps can help reduce water contamination and its problems:

  • Store fluids indoors in a dry location; for those that must be stored outdoors, use tarps and platforms to minimize water exposure
  • Carry out periodic checks on all seals, gaskets and flanges to ensure that there are no system leaks
  • Replace worn or damaged seals on equipment as well as on fluid storage containers
  • Monitor your fluid’s water content through regular fluid analysis
  • Never hydrotest vessels or piping with water. It is much safer to use a dry gas instead
  • Use a dedicated pump and line for system fills to avoid risk of cross contamination
8 - Is Isel new to the heat transfer market?

Isel has been involved with the research, design and manufacture of thermal fluids for well over two decades. Our heat transfer fluids have been successfully heating major facilities through our distribution network under various private label brands.

In January 2018, Isel rebranded our heat transfer fluid line under the name Caldera Heat Transfer Fluids.

We know thermal fluids inside out. Our technical support team is also very familiar with the details of the numerous applications in which they are deployed.

9 - Does Isel offer a free fluid analysis program?

Yes, Isel offers a complimentary fluid analysis program. Our general fluid analysis program includes tests for parameters like flash point, viscosity, Total Acid Number (TAN) and moisture content. We can also offer tests for Initial Boiling Point, Fire Point, Particle Count, etc.

10 - My previous heat transfer fluid has cracked or oxidized, what do I do?

If previous fluid is cracked, we have can help eliminate the cracked fluid's byproducts at minimal cost. 

In some thermal cracking cases experienced by our customers with competitive brands, we have been able to vent the low boilers and top off the system with Caldera Heat Transfer Fluids. This resulted in a restoration of fluid properties to extend the life of the fluid in the system. 

If you are dealing with fluid oxidation, Rescue heat transfer fluid and Caldera 16 (heat transfer fluid and cleaner) are also fully compatible with any mineral oil based thermal fluid.

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