• UNx Fluid End 4215HF-Fluid-End UNx-Cutaway

4220 UNx Fluid End - #8 Plungers

Part No: 51995

Convert an existing Jetstream 4200 UNx® Pump to higher flow or operating pressure in just minutes. Flow up to 14.3 gpm (54 l/min) at up to 20,000 psi (1400 bar).

The Unx Fluid End is a cost-effective solution to increase the available operating pressure or range of pressures of an existing Jetstream 4200 UNx Pump. These fluid end models deliver all of the benefits that define UNx Fluid Ends as the best in the industry.

  • Superior performance
  • Greater flexibility in the field
  • Reduced downtime and maintenance


Model Name 4220
Maximum Power (hp) 185
Maximum Operating Pressure (psi) 20000
Maximum Flow (gpm) 14.3
Minimum Flow (gpm) 4.2
Maximum Power (kW) 138
Maximum Operating Pressure (bar) 1400
Maximum Flow (l/min) 54
Minimum Flow (l/min) 16
Plunger Size #8
Plunger Diameter (in) 0.8
Plunger Diameter (mm) 20.32
Number of Plungers 3
Plunger Stroke (in) 4.25
Plunger Stroke (mm) 108
Discharge Port Connection Jetstream 20K Port Female
Accessory Port Connections Jetstream 20K Port Female
Number of Accessory Ports 3
Suction Port Connection 2"NPT Female
Minimum Pump Speed (RPM) 150
Maximum Pump Speed (RPM) 514
Flow at 150 RPM (gpm) 4.2
Flow at 200 RPM (gpm) 5.6
Flow at 300 RPM (gpm) 8.3
Flow at 400 RPM (gpm) 11.1
Flow at 500 RPM (gpm) 13.9
Flow at 514 RPM (gpm) 14.3
Flow per Revolution (gal/rev) 0.0278
Flow at 150 RPM (l/min) 16
Flow at 200 RPM (l/min) 21
Flow at 300 RPM (l/min) 31
Flow at 400 RPM (l/min) 42
Flow at 500 RPM (l/min) 53
Flow at 514 RPM (l/min) 54
Flow per Revolution (l/rev) 0.105
Power End Model 4200

UNx Conversion Video

This video highlights the ease of maintenance and pressure convertibility of Jetstream UNx Pump. (3:59)

20K Bypass Valve - Pump Mount

A bypass valve diverts a portion of pump flow to a low- pressure outlet and is used to prevent bogging of diesel engines when using flows at the low end of the pump’s capability or to adjust pressure on electric motor driven systems.  20,000 psi (1400 bar).  Pump-mounted.

20K Handle-Adjustable Regulator

Maintains constant system pressure when operating one or more shut-in devices. Knob-adjustable. Field-replaceable valve cartridge. For operation at 15,000 - 20,000 psi (1000 - 1400 bar). Pump-mounted.

UNx Spare Parts Packages

Packages include all major fluid end replacement packaged together for easy transport and storage.

20K Pressure Gauge (psi) - Jetstream 20K Port Male Inlet

0 - 35,000 psi scale. 1,000 psi graduations. Working pressure up to 20,000 psi. Jetstream 20K Port Male connection.

20K Rupture Disc Holder - 20K Port Male

Prevents over-pressurization of waterblasting systems using inexpensive and easily replaceable discs manufactured to burst at predetermined pressures. For operating pressures up to 20,000 psi (1400 bar). 20K Port Male connection.

20K Relief Valve - 20K Port - 18,000-24,000 psi (1240-1655 bar)

Factory set to open at customer specified pressures to prevent system overpressurization. For operating pressures from 15,000 - 20,000 psi (1000 - 1400 bar). 20K Port Male connection.

4200 UNx Bareshaft Pumps

4200 UNx triplex pumps can handle input power up to 325 hp (242 kW). Output from 63 gpm at 8,000 psi (238 l/min at 550 bar) to 11.9 gpm at 40,000 psi (45 l/min at 2750 bar).

4200 UNx Fluid Ends

Increase the range of available operating pressures for any Jetstream 4200 UNx Pump with additional fluid ends. Conversions take only minutes and are available for pressures up to 40,000 psi (2750 bar).