How to Start Up and Shut Down a Heat Transfer System
Many facility operators often overlook the startup and shutdown of their heat transfer system and its effect on the heat transfer fluids. The proper operation of a heat transfer system is critical for fluid longevity, overall heat transfer efficiency, and maintenance cost reduction.
In this article, we present several good practices applicable to the startup and shutdown of a heat transfer system. As always, consult your system manufacturer and maintenance personnel before making any changes to procedure.
System Start
Always start the pump before turning on the heater. Proper fluid flow prior to heating reduces the residence time of the fluid on the heated surfaces, allowing for a steady rise in temperature and helping to prevent fluid cracking.
- Start the burner on the low fire setting, circulate heat transfer fluid at full flow and slowly raise the temperature.
- Once there is circulation through the heater, the operator should increase the temperature of the bulk fluid by 20 to 25°F (11 to 14°C) increments until the fluid reaches a viscosity of 10 cP.
- Ensure that burner flame impingement is well distributed across boiler tube cross section.
- Once the fluid reaches 220°F and is pumping smoothly without cavitation, follow the manufacturer’s recommendation for a full fire heat up.
System Shutdown
The critical element for the longevity of heat transfer fluids is that the fluids in systems are circulating while the system operates at temperature.
- During a shutdown of the system, heat must be decreased proportionately, in the reverse of the startup procedures.
- Keep the fluids circulating until system temperatures drop below the 200°F (93°C mark), so that the residual heat is removed.
For more information on heat transfer fluid best practices and additional technical support needs, contact us today.