Preparing and Starting a Freshly Filled System

This document serves as a general guide for starting a new or recently refilled system. Always follow appropriate safety practices and consult your equipment manufacturer for detailed, system-specific procedures to ensure a safe and efficient startup.

System Preparation

1. Conduct a general inspection of the system before moving forward. Verify that all pipes, flanges, and valves are properly installed and tightened, and confirm that valves are set in the correct open or closed position before introducing fluid into the system.
2. Check the system for the presence of water that may have entered during construction, pressure testing, or other processes. While specific procedures may vary by manufacturer, a common approach includes opening low-point drains and purging the system with nitrogen or dry air to ensure it is completely dry before filling. Avoid using standard or moist air, as this can add additional water to the system.

Filling the System

Once system integrity has been verified and all water removed, the filling process can begin.

1. Consider both ambient and fluid temperatures, as these affect viscosity. Ensure appropriate pumps are available for charging the system. Refer to your Duratherm fluid property chart for viscosity at the fill temperature.
2. Open all high-point vents and valves connected to the various system users.
3. Introduce fluid at the lowest point of the system to minimize air entrapment. This is typically near the pump. In some cases, the system pump may be suitable for filling; otherwise, a portable high-velocity pump or bulk delivery truck pump may be used.
4. Fill the system gradually, closing bleed vents as the fluid level reaches each one.
5. Filling is generally complete when the expansion tank level rises slightly above the low-level switch. Confirm the correct expansion tank level with your manufacturer. If overfilled, drain fluid to maintain the proper level, keeping in mind that fluid expands as it heats.
6. If your system employs an inert gas (commonly nitrogen) on the expansion tank, consult your manufacturer’s instructions for correct initialization. In most cases, Duratherm fluids only require a low-pressure nitrogen pad to reduce oxidation.

Starting the System

1. Confirm that the system pump has been set up per the manufacturer’s instructions. Follow procedures for mechanical and air-cooled seals, which typically require venting of air. Duratherm fluid can often be used as the barrier fluid if necessary.
2. Once the system is ready for operation, follow the manufacturer’s startup sequence. This usually includes performing pump and boiler tests or checks.
3. When circulation is established, leak-free, and stable, continue following manufacturer guidance. In most cases, the fluid should be heated gradually—particularly through the range of 121°C to 149°C (250°F to 300°F)—to allow safe venting of any moisture and to prevent pump cavitation.
4. After startup, take advantage of our complimentary fluid analysis program by sending in a baseline fluid sample. Establishing this reference point provides valuable data for diagnosing fluid-related issues in the future.