The PRESO 753 is a spring-loaded differential pressure regulator designed to progressively open a bypass line as differential pressure increases. It is engineered to maintain minimum pump flow rates, regulate thermal bypass loops, and reliably manage condensate pressure.
PRESO 753 · ANSI Class 150
Pumps · Thermal Fluid · Condensate
NPS ½″ to 4″ · Stainless steel bellows
Maintaining flow and controlling pressure across your piping network
The ARI PRESO 753 is a spring-loaded differential pressure regulator engineered to open proportionally as differential pressure increases. Installed on a bypass line, it diverts fluid flow to maintain continuous circulation throughout your system. Its robust design features a dedicated regulating plug and metallic bellows stem sealing for dependable, leak-free operation.
01
Self-operated
A spring automatically controls the disc's opening based on the differential pressure.
02
Minimum Flow Rate
A bypass line equipped with a PRESO unit can help maintain the required flow for the pump.
03
Bellows Seal
Stainless steel metal bellows for external stem sealing and controlled, reliable maintenance.
04
ANSI Design
Class 150 design, NPS diameters, and materials engineered to meet the demanding requirements of your industrial facilities.
Spring-loaded technology designed to maintain minimum pump flow, regulate thermal bypass lines, and control condensate return.
PUMPS · MINIMUM FLOW
PRESO 753 · Pump Bypass
Installed in a pump bypass line, the PRESO opens when the differential pressure reaches the set point. It redirects a portion of the flow back into the system, helping maintain the required minimum circulation as demand drops.
Function
Pump Bypass
ANSI Class
150
NPS Sizes
½″ to 4″
Order
Self-contained spring
Engineered for circulation pumps, transfer piping networks, and systems requiring reliable minimum continuous flow.
BYPASS · THERMAL CIRCUITS
PRESO 753 · Thermal Oil
In thermal oil systems or heat exchanger bypass loops, PRESO reliably diverts flow as demand fluctuates. Its differential pressure control helps maintain continuous circulation throughout the process loop.
Function
Thermal Bypass
Δp Setpoint Adjustment
0.5 to 10 bar
Sealing Solutions
Stainless Steel Bellows
Construction
Fig. 753
Engineered for thermal oil systems, heat exchangers, and industrial circulation loops.
CONDENSATE · DIFFERENTIAL PRESSURE
PRESO 753 · Condensate Systems
In condensate recovery systems, PRESO helps maintain adequate pressure and minimize the risk of flashing. It is also ideally suited for bypass lines subject to differential pressure fluctuations.
Function
Pressure Sustaining
Control
Proportional
Materials
Cast iron · Carbon steel · Stainless steel
Sealing Solutions
Metal bellows
For condensate return systems and applications requiring precise system pressure control.
PRESO or PREDU: Which Valve Function Best Suits Your Process?
PRESO and PREDU are both self-operated regulators, but they serve distinct functions. The PRESO controls differential pressure and bypass flow, while the PREDU reduces the supply pressure to a defined downstream setpoint.
Target Application
PRESO · Pump Protection
Automatic bypass to maintain continuous flow during periods of low system demand.
PRESO · Thermal Fluid
Bypass flow management in thermal loops and heat exchangers.
PRESO · Condensate
Backpressure control on select return lines to mitigate flash evaporation.
Sizing Data
Differential pressure
Desired setpoint between inlet and outlet pressures.
Bypass flow rate
Minimum or maximum relief flow rate required through the bypass line.
Fluid Handling & Connections
Fluid media, temperature, NPS, pressure class, and flange configuration.
Need to size a pump minimum flow or bypass line? Send us your operating conditions for a fully documented PRESO selection backed by local expertise.
ARI PRESO for Pumps, Thermal Fluid Circuits, and Condensate Systems
The PRESO differential pressure regulator seamlessly integrates into systems where flow or pressure fluctuations require precise, automated control.
DESIGN AND OPERATION
Key Advantages of the ARI PRESO 753 Pressure Regulating Valve
Figure 753 combines spring-loaded actuation, proportional characteristics, and bellows sealing. A wide range of materials and set-pressure ranges ensures an engineered construction precisely matched to your service conditions.
Spring-operated actuation
Modulating opening based on differential pressure, requiring no electrical or pneumatic power source.
Integrated stainless steel bellows
The metal bellows provides external stem sealing, complete with disc guiding.
Four spring ranges
Differential pressure ranges of 0.5–1.5, 1–3, 2–5, and 4–10 bar, depending on the selected spring.
Request a quote for the PRESO 753
To select the appropriate regulator and spring range, please provide your bypass line operating conditions.
Applications
Pump, thermal, or condensate systems
Specify the valve function and flow pattern.
Pressure Ratings
Inlet and Outlet
Specify the upstream and downstream pressures as well as the target differential.
Flow Rate
Bypass flow rate
Please provide the required minimum flow rate or bypass flow rate.
Assembly
NPS and Flanges
Specify nominal size, pressure class, and operating temperature.
Complete your system with ARI's full range of complementary product lines
PRESO specializes in differential pressure applications. Also explore PREDU for downstream pressure reduction, SAFE/REYCO for critical equipment safety, and ARI systems for engineered, pre-assembled steam packages.
Pressure Relief
ARI PREDU
Self-operated pressure reducing valves designed to reliably reduce and stabilize downstream system pressure.
Safety
ARI SAFE / REYCO
Industrial safety relief valves designed to protect your pressurized equipment.
Steam Systems
ARI SYSTEMS
Industrial packages for steam, pressure reduction, and condensate management.
FAQ
Differential pressure, minimum flow, pump bypass, thermal oil, and ANSI-compliant versions.
Need to size a PRESO bypass or regulator?
Whether for a replacement or a new project, simply send us your pressure ratings, flow rate, and pipe dimensions. VAMECA will guide you in selecting the right Figure 753 model, as well as the optimal materials and spring configuration.
Your Local Technical Contact in Quebec
Technical consulting and quotes for Canadian industrial facilities.
Technical Product Selection
Regulator selection based on differential pressure, flow rate, and process fluid.
Manufacturer Documentation
PRESO technical data sheet and selected construction specifications.
