Danfoss HFI Float Valve (High Pressure)

Introduction

This document provides comprehensive installation and maintenance instructions for the Danfoss HFI Float Valve (High Pressure).

Installation

Refrigerants

The HFI valve is applicable to all common non-flammable refrigerants, including R717, and non-corrosive gases/liquids, provided they are compatible with the sealing material. The float ball is standard for R717 with a density of 500 to 700 kg/m³. For refrigerants with densities outside this range, contact Danfoss. Flammable hydrocarbons are not recommended. The valve is recommended for use in closed circuits only. For further information, please contact Danfoss.

Temperature Range

HFI: -50/+80 °C (-58/+176 °F)

Pressure Range

The HFI valve is designed for a maximum pressure of PED: 28 bar g (407 psi g). The float ball is designed for a maximum working pressure of 25 bar g (363 psi g). If the test pressure exceeds 25 bar g (363 psi g), the ball should be removed during testing.

Mounting

Mount the float valve horizontally with the outlet connection (labeled A in Figure 1) vertically downwards. The flow direction must be from the flanged inlet connection as indicated by the arrows (Figure 1).

The valve is designed to withstand high internal pressure. However, the piping system should be designed to avoid liquid traps and reduce the risk of hydraulic pressure caused by thermal expansion. Ensure the valve is protected from pressure transients such as "liquid hammer" in the system.

Welding

Remove the float assembly before welding:

• Dismount the end cover and remove the transport packing.
• After welding and assembly, replace the transport packing until the unit reaches its final destination.
• Unscrew the screw (position C in Figure 1) and lift the float assembly from the outlet.
• Weld the outlet connection (position A in Figure 1) into the plant as shown in Figure 2.
• Use only materials and welding methods compatible with the valve housing material.
• Clean the valve internally to remove welding debris upon completion of welding and before reassembly.

Avoid welding debris and dirt in the housing.

Note: When demand is heavy at low temperature operation, check the velocity in the outlet branch. If necessary, the diameter of the pipe welded to the outlet branch (position A in Figure 1) can be increased. The valve housing must be free from stresses (external loads) after installation.

Assembly

Remove welding debris and any dirt from pipes and the valve body before assembly.

Replace the float assembly in the outlet branch and tighten the screw (position C in Figure 3). Check that the float assembly is fully seated in the outlet connection and that the float ball is positioned in the middle of the housing, allowing unrestricted movement.

Remount the end cover with the purge valve and pipe in the housing. The ventilating pipe (position E in Figure 3) must be placed vertically upwards.

Note: If an insert with a slide (version before 2007) was replaced by the current version, an extra threaded hole needs to be made in the outlet connection A to fix the screw (Figure 1).

Tightening

Use a torque wrench to tighten the screws (position F in Figure 3). Tighten to a torque of 183 Nm (135 LB-feet).

Colours and Identification

The HFI valves are painted with a red oxide primer from the factory. The external surface of the valve housing must be protected against corrosion with a suitable protective coating after installation and assembly. Protection of the ID plate when repainting the valve is recommended.

Maintenance

Purging of Incondensable Gases

Incondensable gases may accumulate in the upper part of the float valve. Purge these gases using the purge valve (position G in Figure 4).

Replacement of Complete Float Assembly

Follow these steps to replace the complete float assembly (adjusted from the factory):

1. Note: Before opening the float valve, the system must be evacuated and the pressure equalized to atmospheric pressure using the purge valve (position G in Figure 4).
2. Remove the end cover.
3. Remove the float assembly by untightening the screw (position C in Figure 5) and lifting out the complete float valve assembly.
4. Place the new float assembly in the outlet connection (position A) and tighten the screw (position C in Figure 5).
5. Remount the end cover with the purge valve and pipe onto the housing.
6. Note: The ventilating pipe (position E in Figure 5) must be placed vertically upwards.
7. Use a torque wrench to tighten the screws (position F in Figure 5). Tighten to a torque of 183 Nm (135 LB-feet).
8. Note: Check that the purge valve is closed before pressurizing the float valve.

Use only original Danfoss parts for replacement. The materials of new parts are certified for the relevant refrigerant.

In cases of doubt, please contact Danfoss. Danfoss accepts no responsibility for errors and omissions. Danfoss Industrial Refrigeration reserves the right to make changes to products and specifications without prior notice.

Diagram Descriptions

Figure 1: Installation Overview

Illustrates the float valve with key connection points labeled A (outlet connection) and C (securing screw). Arrows indicate the correct flow direction through the valve.

Figure 2: Welding Outlet Connection

Shows the process of welding the outlet connection (position A) into the plant's piping system.

Figure 3: Assembly Details

Depicts the assembly of the float valve, highlighting screw C for securing the float assembly and the correct vertical orientation of the ventilating pipe E.

Figure 4: Purging Incondensable Gases

Demonstrates how to purge incondensable gases from the valve using the purge valve (position G).

Figure 5: Float Assembly Replacement

Details the steps for replacing the float assembly, showing screw C and the ventilating pipe E.

Figure 6: Float Ball Operation and Pressure Ratings

Provides close-up views of the float ball's state: "Detail / Détail A Fully closed" shows no orifice holes exposed, while "Detail / Détail B Fully open" shows orifice holes exposed. It also displays pressure ratings of 70, 60, 50, and 40, likely indicating capacity or sizing references.