Liquid return temperature limiter | ARI

ARI CONA 650 Return Temperature Limiter

The ARI CONA 650 is a self-acting return temperature limiter for hot water circuits and compatible fluids in heating systems. It regulates flow based on return temperature: the valve opens more as temperature drops and restricts flow as it rises. Even in a closed position, a small flow is maintained to provide the controller with a representative sample of the medium.

Technical Specifications

• Type: CONA 650, Fig. 45.650
• PN: 40
• DN: 15–25 / 1/2"–1"
• Body Material: P250GH / 1.0460
• Max Conditions: 22 barg at 180°C
• Permissible Differential Pressure: 6 bar, controller R22
• Closing Temperature Range: 60–130°C
• Connections: flanges EN 1092-1, thread Rp EN 10226-1 or NPT ANSI B1.20.1, socket weld EN 12760, butt weld per EN ISO 9692.

Applications

Used in:

• industrial heating networks,
• hot water circuits,
• pipe tracing with return temperature limitation,
• heat consumers requiring return control,
• HVAC systems with thermal-hydraulic balancing via temperature.

Suitable media include hot water and compatible fluids. For corrosive, abrasive, or special media, material and resistance list checks are required. The version with external adjustment is not intended for Group 1 fluids.

Options and Adjustment

• Thermometer with adapter for local temperature indication.
• External adjustment device for setpoint change without operation interruption.
• Controller replacement without disconnecting piping.
• Recommended horizontal installation; inclined position of the screw cap is allowed, maintaining flow direction.

Maintenance and Leakage

Before startup, check material, pressure, temperature, and flow direction. Welding residues or contaminants in the piping can cause internal leakage. In case of reduced flow or non-closing, check the controller, setting, seat, and differential pressure conditions.

FAQ

Does it require an actuator?
No. Operation is via a bimetallic thermostatic controller.

When is it selected?
When return temperature needs to be limited to a specific setpoint, rather than simple flow regulation.