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Introducing PH5 – the Newest Member of the PowerHalt Family

PowerHalt's PH5 Air Intake Emergency Shut-Off Valve is the newest member of the PowerHalt family. This newly improved valve is designed using the best aspects of PH2 and PH3 PowerHalt line of products. It is electrically activated and available in an automatic engine speed sensing model where shutdown occurs if engine speed exceeds a user-set trip speed (or by manual override). Alternatively, a manual control configuration is available where an operator or external input will activate emergency engine shut-down.

PH5 Highlights

  • Universal Applications
  • 1.75" to 5.0" sizes available
  • Operator friendly operation with manual reset and override
  • High temperature design for challenging thermal applications
  • Rigorous vibration, corrosion and endurance testing
  • In compliance with CSA B621-14 & B622-14
  • Easy installation and low part count

PH5 Specifics

  1. Large Visible Reset Knob
  2. Electrical Activation Options
  3. Valve Position Feedback (optional)
  4. Corrosion Resistant Materials
  5. Maintenance Free Butterfly Valve Design
  6. 12 VDC or 24 VDC Systems
  7. 1.75-5” Valve Sizes Available

PH5 Control Options & Components

  1. POWERGUARD CONTROLLER (AUTOMATIC) Monitors engine speed through a gear tooth sensor mounted to the transmission bell housing using an existing auxiliary port or by the drilling and tapping of a new port. The controller has a programmable trip point – when the programmed pre-set speed is exceeded, emergency engine shutdown will occur automatically. Emergency shutdown can be activated at any time through a manual override switch
    ■ Automatically activates after programmable engine speed trip point is exceeded
    ■ Manual override from cab/panel mounted switch
  2. TOGGLE SWITCH Military style switch with safety cover to prevent false trip hazards. Provides a manual means to shutdown the engine or test the valve
  3. MAGNETIC PICK-UP Measures flywheel RPM and sends a signal to shut down the engine when engine runaway occurs
  4. PANEL INDICATOR LIGHT Get instant notification on the status of your PowerHalt valve with this LED panel indicator warning light for your dash (optional)

PH5 Kits Include:

  • All necessary hose adapters, clamps, and hardware required for an install
  • Weather tight plug & play wiring harness. Easy to install kits for universal applications
  • Control option available with PowerGuard automatic overspeed limiter and manual reset

Technical Support


Jason will be guiding you through troubleshooting the magnetic speed sensor included with your PowerHalt Air Intake Emergency Shut-Off Valve by Pacbrake.

FAQs and Troubleshooting

How do I know if my valve is closed?

All of the manual reset PowerHalt Shut-Off Valves (PH1, PH2, PH5) have a large red reset knob which indicates the position of the flap within the valve. The PH2 and PH5 shut-off valves also have an option to include a microswitch as an electronic indicator of valve position.

The switch is available in Normally Open and Normally Closed configurations. The wiring from the switch can be led to a panel light or fed directly into your equipment systems.

How much power does my PowerHalt system require?

Electronic activation PowerHalt systems can be powered by 12 or 24 VDC. Manual activation kits are specific to either 12 or 24 VDC whereas the automatic activation kits are universal to either power source.

Once connected to power, manual activation kits will draw near 0mA of current while automatic activation kits will draw 30-35mA at idle.

Can I use my PH5 PowerHalt system to protect my auxiliary PTO/work-mode equipment?

No, you can't

How do I choose my PowerHalt air shut-off valve trip speed?

If you have control over the engine speed: choose to set your trip speed at 30% above the engine rated RPM. Refer to your programming manual for set-up procedure.

If your engine runs at a constant speed: you can choose to set your trip speed at 10, 20, or 30% above the constant engine speed. Refer to your programming manual for set-up procedure.

Can manual reset be achieved easily and without placing workers at risk?

Frequent security checks may prove cumbersome when manually resetting a valve if it is difficult to access. Automatic reset are better suited for these applications. Routing of the switch or pill cable is an important consideration to make. Pull cable are a great low cost option if your application and regulations allow.

Can the valve incorporate multiple auxiliary inputs from an external source?

No, the PH5 configuration can't. You will need a PH3 air shut-off valve for this particular requirement

What can I do about an offset flywheel?

In some cases, the factory sensor port on the bellhousing does not line up directly over the flywheel teeth. The sensor port may give a partial view of the flywheel which is offset by a gap or a machined edge. It is possible that a threaded speed sensor will not be able to sense speed from an offset flywheel.

Pacbrake recommends first installing the sensor into the port and checking if the system is able to read speed. You can check that the sensor is detecting speed by proceeding to Set and Test a Trip Speed. If setting and testing occur successfully, the sensor is able to read speed.

If the sensor cannot read speed, contact Pacbrake Support for an offset adapter (P/N: C50136) and a 3/8”-20 gear tooth speed sensor. The offset adapter is a sleeve with a 3/4”-16 external thread and a 3/8”-20 hole drilled off-center to allow the smaller sensor to be positioned directly over the offset flywheel teeth.

A more immediate solution would be to drill and tap a new sensor port in the correct position on the bell housing.

Warranty Registration

Register your product for warranty HERE.