Debunking the Myths Surrounding Thermal Heaters

.Thermal fluid systems or thermal heaters have been in use since over 80 years, yet there are many myths that surround them and they are considered a source of fear, anxiety, and paranoia in users. These myths are further fueled by a number of stories that the users might have heard. For example:

• Thermal heaters developing certain problems
• An outbreak of fire near the pump
• The heater room filling up with smoke.

This is mostly due to a lack of explanation of the actual causes, and not the result of some mysterious phenomena. Such myths can be easily debunked by understanding the underlying causes and how one can prevent such occurrences in the future.

Myth 1: Water Will Always Be Present in Thermal Fluid that is New

When a new thermal fluid is added to the thermal heater, sometimes hot liquid can eject or ‘geyser’ out of the expansion tank and into the catch tank and onto the floor of the heater room. Another problem that occurs is that the pump begins to cavitate during startup. The truth is that every new thermal fluid will contain some amount of water, usually about 150 ppm.

That’s why it is recommended to do a ‘boil-out’ of the system before a cold startup. This removes the water from the new thermal fluid. As well as eliminating any trace quantities of water present in the piping and components.

Myth 2: The Pump Seal is Leaking Because the Thermal Fluid is Faulty

A leaking pump seal is a cause of worry because they are often the source of fires associated with thermal fluids. A seal is the only component of a thermal heater where there is no presence of a metal between the air and the combustible fluid. Hence, the leak itself is always the fuel, even if the source of ignition is unknown. A seal leaks because of the buildup of carbon on the outer surface and carbon can break apart the seal faces, resulting in a leak.

This doesn’t mean that there is something wrong with the thermal fluid. This is mostly due to replacement seals that are worn out or have been poorly installed. The solution is to put a mesh screen of a scale 60+ in the pump section of a new thermal fluid heater or in an existing system where new components were installed or where the piping was opened.

Myth 3: The Top Drum is Open So it Will Make the Perfect Catch Tank

A common myth albeit not even remotely true. The catch tank accumulates the discharges of the relief valves and the vent of the expansion tank. This discharge might include dangerous by-products of fluid degradation and water, with the frequent liquid geyser from the trapped water. Therefore, it is not favorable to utilize any liquid from the catch tank; doing so can cause the volatile compounds and the water to vaporize. These end up on the floor of the tank or in the tank itself.

A good practice is to drain the catch tank on a frequent basis.