Old trane centrifugal chiller with prevac installed


Mechanical Ingenuity Corp. has been manufacturing PREVAC for over 30 years. Originally designed for R-11 low pressure chillers, and continued on R-123 chillers, it was an industry leading add-on for Trane, York, and Carrier units. Now, with the new R-1233zde chillers, PREVAC continues to add value to the building owner through cost savings and safety and code compliance, and to service contractors as a service tool that keeps their service people safe and their customers happy.

Prevac components

PREVAC Stationary System

The PREVAC System enhances the operation of low pressure chillers using refrigerants R-1233zd, R-123, and R11. PREVAC prevents air & moisture infiltration in stand-by idle chillers, eliminates surging on start-ups, and prevents acid damage and refrigerant release. It also eliminates electrical code violations during servicing, by eliminating the need for temporary high voltage and temporary water hose connections. The PREVAC system provides 1/100 of 0.0 PSI control for minor repairs and features a high pressure alarm before the bursting disc is activated. This system complies with Ashrae 147, and enables safe and efficient chiller servicing.  

The stationary PREVAC system provides:

  • “Pressure Seal” Mode 0.00psig Fixed Set Point
  • “Leak Test” Mode 0.00 to 6.00psig Adjustable Setting
  • 1/100 psi Accuracy
  • Proportional Control
  • Pressure Activated and/or Electrically Interlocked
  • Water Heating Vessel
  • Fully Temperature Controlled
  • 20kW 480v or 12kW, 240v Heating Capacity
  • Stainless Steel Housing for Heaters
  • 350 psi Pressure Rating
  • 30 gpm Pump
  • High Pressure Warning & Disconnect
  • 30 amp Circuit Breaker
  • Audible and Visual Alarms
  • High Pressure Trip
  • BAS Interface

Purchase Price: $6,250           Rental Price: $950/yr 

Portable Prevac

PREVAC Portable Pressurization System

PREVAC Portable is a state of the art pressurizing system which provides unparalleled performance and safety in raising the water temperature inside the evaporator of a low pressure centrifugal chiller for the purpose of leak testing and performing minor repairs at zero pressure in compliance with the EPA Clean Air Act. 

Benefits of the mobile system:

  • 20,000 watts of power
  • Pressure and temperature controlled
  • Pressure readout in 1/100 psi increments
  • Adjustable pressure set point from 0 to 6 psig
  • Pump can be operated independently
  • Stainless steel construction
  • Requires only one supply voltage for all components
  • Features a lightweight aluminum cart with pneumatic tires
  • Total weight 75 lbs


  • 20kW, 480 volts
  • 12kW, 240 volts

Price: $6,895.00

PREVAC installed on chiller

Maximize the Lifetime of Your Equipment

Chillers are expensive and integral pieces of equipment in a building's operation. Why not get the most out of them? And have them run better? PREVAC is a cost saving insurance policy for you as a building owner.  

Prevac installation service technician

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30,000 Units Installed Worldwide

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PREVAC is trusted by some of the world's biggest companies. Click here to see a list of some of our clients.

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