Coliter ® Self Pressure Differential Control Valve – PN16, 0~100°C, Constant ΔP Regulation for HVAC & Heating Systems
ZYC Self Pressure Differential Control Valve – Self-Operated Hydraulic Valve Maintaining Fixed Pressure Difference in Closed Water Circuits
The Coliter® ZYC Self Pressure Differential Control Valve is a self-operated regulating valve designed to maintain a constant pressure difference (ΔP) across a controlled loop in closed water circulation systems—such as hot water heating, chilled water HVAC, and district energy networks. It automatically compensates for both external disturbances (e.g., network pressure fluctuations) and internal changes (e.g., valve adjustments or load variations), ensuring stable flow distribution, eliminating hydraulic imbalance, reducing noise, and protecting terminal units from overflow. The valve requires no external power supply, using system pressure feedback via impulse lines to modulate the valve disc position through a diaphragm actuator. Available in two types: fixed differential pressure (factory-set at 10 kPa, 20 kPa, or 30 kPa) or adjustable (field-selectable within range). Constructed with a gray cast iron or cast steel body, stainless steel stem, cast copper disc, and nitrile rubber diaphragm, it offers robust performance under demanding conditions. Rated at PN16 (1.6 MPa), it operates within a temperature range of 0℃ to 100℃ and handles media such as water and non-corrosive liquids. Compliant with standards including GB/T 21387 and API 6D, available in sizes from DN15 to DN300 with threaded or flanged connections per GB/T 9124.1, HG/T 20592, ASME B16.5. By stabilizing differential pressure, the ZYC enables energy-efficient pump operation, balanced terminal performance, and long-term system reliability—making it essential for modern variable-flow hydronic systems.
Installation diagram
Product Description
| DN | Connection mode | L(mm) | Size(mm) | flow m/h | Applicable media | Medium temperature | Materials of main parts | |
|---|---|---|---|---|---|---|---|---|
| Constant differential pressure type | Adjustable differential pressure type | |||||||
| 15 | Threaded flange | 110 | 95 | 142 | 0.2-1 | water | 0–100°C | Valve body, upper cover and the lower cover is cast iron the valve core is copper diaphragm Nylon reinforced rubber the spring is stainless steel. |
| 20 | 110 | 110 | 150 | 0.5-1.5 | ||||
| 25 | 115 | 130 | 165 | 0.5-2 | ||||
| 32 | 130 | 140 | 190 | 1-4 | ||||
| 40 | 200 | 190 | 340 | 1.5-6 | ||||
| 50 | 215 | 205 | 355 | 2-8 | ||||
| 65 | 230 | 240 | 390 | 3-12 | ||||
| 80 | 275 | 300 | 500 | 5-20 | ||||
| 100 | 290 | 350 | 550 | 10-30 | ||||
| 125 | 310 | 380 | 580 | 15-45 | ||||
| 150 | 350 | 453 | - | - | ||||
| 200 | 430 | 532 | - | - | ||||
| 250 | 520 | 632 | - | - | ||||
| 300 | 637 | 728 | - | - | ||||
This product is a self operated regulating valve of open and closed water circulation system (such as hot water heating system, air conditioning chilled water system, etc.). Its function is to keep the pressure difference of the controlled loop constant when there is external disturbance (pressure fluctuation of the network) and internal disturbance (change of internal resistance) in the controlled loop. It is suitable for heating mode. The pressure difference control of double pipe system is adopted to ensure the stability of the system, reduce noise, balance resistance, fire heating network and hydraulic imbalance. Whether the network pressure fluctuates or the resistance inside the controlled loop changes, ZYC self-supporting differential pressure control valve can maintain the constant differential pressure applied to the controlled loop.
Performance Standard
| Design Standard | GB/T21387, API 6D |
| Structure Length Standard | GB/T21387, API 6D |
| Flange Standard | GB/T9124.1, HG/T20592, ASME B16.5, ASME B16.47 |
| Test Standard | GB/T21387, API 6D |
Main Performance Specification
| Nominal Pressure | 1.6MPa |
| Nominal Diameter | 15–125mm |
| Applicable Media | Water, non-corrosive liquids (e.g., water, oil, etc.) |
| Operating Temperature | 0–100°C |
| Differential Pressure Control Range | Fixed type: 10KPa, 20KPa, 30KPa |
Materials of Main Parts
| Part Name | Material |
|---|---|
| Valve Body | Gray cast iron, cast steel |
| Stem | Stainless steel |
| Disc | Cast copper |
| Diaphragm | Nitrile rubber |
Product Inquiry
We will contact you within one working day. Please pay attention to your email.
Faq - Frequent questions
Introduction to Differential control valve
Coliter®’s differential control valves automatically maintain stable pressure differentials in heating, cooling, and variable-flow HVAC systems to ensure balanced operation and protect equipment. The series includes the ZYC self-operated differential pressure control valve, which uses system pressure feedback to modulate flow without external power, and the 800X differential pressure bypass balance valve, which diverts excess flow between supply and return lines when ΔP exceeds setpoint. Constructed from high-quality brass or cast iron, these valves are rated at PN16 (1.6 MPa) and suitable for temperatures up to 120°C. They enable energy-efficient pump operation, prevent coil overflow, and eliminate noise—ideal for chiller plants, underfloor heating manifolds, and district energy networks.
