Model 4800A is a High Flow Pneumatic Volume Booster specifically designed for Valve and valve actuation systems. With its Cv of 9 in both forward and exhaust modes, this pilot-operated booster provides fast response and accurate control for valve actuation.
Operating Principles
When signal pressure on the top of the Signal Diaphragm creates a downward force on the Diaphragm Assembly, the Supply Valve opens. Output pressure flows through the Outlet Port and the Aspirator Tube to the Control Chamber to create an upward force on the bottom of the Control Diaphragm. When the setpoint is reached, the force of the signal pressure that acts on the top of the Signal Diaphragm balances with the force of the output pressure that acts on the bottom of the Control Diaphragm to close the Supply Valve.
When the output pressure increases above the signal pressure, the Diaphragm Assembly moves upward to close the Supply Valve and open the Exhaust Valve. Because the Poppet Valve is closed, pressure flows down the Connecting Tube to the bottom of the Motor Diaphragm. This pressure keeps the Supply Valve tightly closed while in the exhaust mode. The Poppet Valve opens and excess output pressure exhausts through the vent in the side of the unit until it reaches the setpoint.
Features
Model 4800A Volume Booster Features
- An integral bypass valve, for optimum tuning and adjustment, even while in operation, to obtain maximum performance on opening and closing times with minimal overshoot or oscillation
- In its pilot-operated regulator design, the M4800A handles up to 250 psig, [17.0 BAR], (1700 kPa) supply pressure and delivers an output pressure up to 150 psig [10.0 BAR] (1000kPa)
- Cv = 9; Flow capacity of 500 SCFM (850 m3/HR) - fast response for quick valve opening and closing times
- Ratio accuracy of 0.5% - highly accurate valve control for your system
- Fixed deadband between the operation of the supply valve and exhaust valve provides accurate and stable final positioning of the valve
- Integral bypass needle valve optimizes response time and stability
- Soft seat supply and exhaust valves provide efficient leak-free operation and prevent hunting, especially when used with modern electronic feed & bleed type valve positioners
- Pressure-balanced supply valve maintains deadband specification, preventing changes in control characteristics when supply pressure changes
- Damped diaphragm control chamber protects valves from damaging oscillation under high flow conditions
- Two accessory ports connected to the outlet chamber provide convenient access to the outlet for additional control accessories and pressure monitoring
Specifications
Model 4800A Volume Booster Specifications
Dimensions
Model 4800A Volume Booster Dimensions
Q & A
Model 4800A Volume Booster Q & A
+What are the key technical specifications of the Model 4800A, and how do they apply to valve actuation systems?
The Model 4800A is a high-flow, pilot-operated pneumatic volume booster designed specifically for valve and actuator systems. It boasts a flow capacity of 500 SCFM (≈850 m3/h) and a Cv value of about 9 in both forward and exhaust modes. It handles a maximum supply pressure of 250 psig (≈17 bar / 1700 kPa) and delivers an output pressure up to 150 psig (≈10 bar / 1000 kPa). Additional features include an integral bypass needle-valve for tuning, soft-seat supply and exhaust valves to minimize leaks/hunting, and a pressure-balanced design for stability even when supply pressure varies. In practical terms: if you’re controlling large pneumatic actuators or high-flow valve systems in North America, Europe, or globally, the 4800A is appropriate for applications requiring rapid response, high volume, and precision positioning.
+How do I select and size the Model 4800A for my installation (valves, actuators, flow requirements)?
Sizing involves considering the actuator or valve you need to drive: look at the required flow rate, actuator volume, opening/closing time, and system supply pressure. Since the 4800A offers 500 SCFM and a Cv of 9, it is suited for high-volume systems. If your actuator requires fast stroke times and there is a large volume of air/gas to move, this model offers significant capacity. Confirm that your supply pressure does not exceed the 250 psig rating, that your output pressure requirements align (max 150 psig), and that your piping/port sizes (e.g., ?" or 1" NPT/BSP) match the booster’s options. Also take into account environmental conditions (temperature range from -40 °F to +200 °F or -40 °C to +93 °C) and whether the actuator control system demands minimal overshoot/hunting — the integral bypass feature helps with that. This ensures the booster is neither undersized (leading to slow response) nor over-spec’d (wasting cost).
+What are the installation, maintenance, and compatibility considerations for the Model 4800A?
When installing the 4800A, ensure the supply air is dry, clean, and properly filtered, as oil or contaminants may damage the soft-seat valves. The booster should be mounted with correct orientation and provision for the integral bypass valve adjustment. Verify that port threads match your plant standard (NPT, BSPP, or BSPT) and that the plumbing and exhaust routing support the high flow. For maintenance, inspect for leaks at supply/pilot/exhaust connections, verify tuning of the bypass valve to avoid oscillation, and check that the actuator response remains stable over time. Because soft seats and high-flow elements are involved, material compatibility (body aluminum, trim zinc-plated steel or stainless steel, elastomers such as nitrile or Viton) should align with your media and ambient conditions. In a global context — whether in the U.S., Canada or Europe — factor local service support, availability of spare parts, and compliance with certifications (for example, CRN in Canada) if applicable.
+What are the benefits of using the Model 4800A vs other volume boosters, and what typical applications suit it?
The main benefits of the 4800A include very high flow capacity, fast response, high-precision control (ratio accuracy ~0.5 %), and stability under varying supply conditions thanks to its pressure-balanced design and bypass tuning. Compared to lower-flow boosters, this model is better equipped for large valve actuators, rapid stroke requirements, heavy-duty industrial systems (e.g., oil & gas, chemical, power generation), and where minimizing overshoot/hunting is critical. Typical applications include large pneumatic valve actuation systems, fast-acting relief or control valves, and automated process control systems requiring high volume and precision (in North America, Canada, Europe). Because of its forward/exhaust high flow design and no-bleed construction, energy loss is minimized while performance remains high. Therefore, when a system demands high throughput and accurate valve positioning, the 4800A becomes a top choice.
+What should I expect in terms of pricing, lead-time, and global support for the Model 4800A?
Pricing will depend on configuration (port size, thread type, materials, elastomer options, and optional accessories) and regional distribution. Because this is a high-flow industrial component, it will cost more than basic boosters. It is advisable to request formal quotes from authorized distributors or from Rotork / Fairchild’s network with your specific configuration. Lead-time may vary depending on stock availability, region (U.S., Canada, Europe), and any special material or certification requirements. Given the global footprint of Rotork / Fairchild, global support for service, maintenance, and spare parts is available — this is important for installations in North America or Europe. Be sure to check that your part number, calibration/spares availability, and local regulatory certifications (such as CRN for Canada) are addressed prior to purchase.
Downloads
Download Rotork Fairchild Model 4800A Volume Booster Datasheet
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