Technical Docs

We understand that your success depends on having knowledge at your finger-tips… so here is the latest information from the Hadley Experts. There’s more to come, so check back often!


Horn Won't Sound

  • Is air coming out of horn?
    •  If yes, look down projector(s) to ensure there is no obstruction / restriction (examples: spider nest, leaf, moth, mud dauber nest, bee hive, etc.). If you find any type of obstruction / restriction remove and try horns again.
    • If no obstruction / restriction found remove back cover and perform cleaning procedure to remove debris from diaphragm seats.
  • If air is not coming out of the horn, check to see if there is air pressure in the tank.
    • If yes:
      • Verify there are no kinks in the nylon air tubing.
      • Check that the solenoid has power (minimum of 10vdc) when the horn button is pushed.
      • If power is available and you do not hear a clicking sound from the solenoid, the plunger is most likely stuck in the closed position and will need to be cleaned (550 Series only).
        • First empty the air from the tank (Do Not attempt to remove solenoid with air pressure in tank as this could result in personal injury) and then remove solenoid in order to perform solenoid cleaning procedure (add link to solenoid cleaning procedure).
    • If there is no air pressure in the tank, please refer to the compressor section.


Compressor FAQ

Q. At what pressure should my compressor shut off?

A. The operating range is 110 p.s.i. +/- 10 p.s.i. (or below) cut in to 135 p.s.i. +/- 7 p.s.i. cut out (plus or minus 10 p.s.i. for gauge variation). A properly operating pressure switch will shut off the compressor when the maximum psi has been reached.

Q. How long should it take to fill the air tank?

A. Small Tank (5″ x 7″) 2.5 to 3 minutes from empty Large Tank (5″ x 14″) 4.5 to 5 minutes from empty

*Do not operate the compressor for more than 7 minutes. Cool down between uses for at least 30 minutes, depending on ambient temperature.

Q. Why won’t my compressor SHUT OFF?

A. There could be several reasons for the compressor not shutting off

  • Check the pressure / air gauge (if equipped, if not equipped install gauge)
    • If the gauge shows no reading, then review the installation instructions for proper assembly.
    • Insure shut off pressure is being reached (135-142), if pressure goes beyond 142p.s.i. and does not shut off replace pressure switch.
    • If not attaining 135-142 p.s.i. continue below.
    • Check for air leaks – All fittings, hoses, outlet at solenoid, tank seam, mounting studs, and welds by submersing the tank in water. Soapy water solution will not always show leaks.
  • Solenoids can easily be checked by putting a small balloon or baggie over the outlet and looking to see if it fills up with air, if it does clean solenoid per the instructions included with your kit when purchased. If you do not have them please refer to the installation instructions for your kit on this site.
  • Check for debris in Check Valve / solenoid, also check for proper orientation of check valve.
  • Additional information on this issue can be found here.

Q. Where can I get replacement parts?

A. Please visit the Find a Distributor page

Q. If I return a part under warranty, how long can I expect warranty evaluation to take?

A. Approximately 2 weeks (allow longer during holidays)

For additional information, please review the other documents in the Technical Docs section. For diagnostic assistance, please contact the Hadley Warranty Center or submit a request through the self-service center.

Compressor Won't Shut Down

  • Check your elevation. If your elevation is 5000 feet above sea level or higher you will need to install a pressure switch that will shut off at 120p.s.i. Check with your local Grainger location.
  • Check pressure gauge to ensure pressure is reaching the correct pressure for automatic shut off (135 +/- 7 psi). If reaching specification and beyond replace pressure switch with part number H13940S (See need a part/ where to purchase Add / create link). If not reaching specification continue below. You may want to verify the accuracy of the gauge by checking with a digital tire gauge that will read up to at least 150p.s.i.
  • Verify your wire connections are clean and solid. You may need to pull on the wire connectors to ensure they are not loose.
  • Verify supply voltage is a minimum of 12 vdc (with vehicle running) coming into and out of pressure switch. If voltage drop is too high replace switch (you can also verify switch is faulty by connecting the two wires from the switch together and see if the compressor builds more pressure). Remember the compressor will not shut off during this verification test.
  • Check your system for air leaks. The best way to do this is to dunk the air tank assembly in water and watch for bubbles, not all leaks will show up using a soapy water solution. If leaks are found repair the air leaks and dunk in water again to verify there are no more leaks.
  • The solenoid may also be stuck in the open position. This will be a result of moisture build up on the plunger inside. This moisture build up is a natural byproduct of the air compressing process. As the air is compressed moisture is created, (much like the water that comes out of the a/c in your automobile). This moisture gets into the tank and is pushed out every time you activate the horn. It then settles inside the solenoid. This process will continue until such time as the plunger inside the solenoid cannot move freely any longer and will need to be cleaned. If the air is leaking from the solenoid please refer to the solenoid cleaning instructions (add link to solenoid cleaning procedure).
  • The secondary check valve (HPB850C) could also be malfunctioning and not allowing the compressor to push the air past it. To verify this you may remove the secondary check valve and replace it with a straight 1/8” NPT male to ¼” compression fitting and start up the compressor. If compressor builds up pressure beyond the previous reading the secondary check valve is faulty, replace it and retest (See need a part/ where to purchase Add / create link)
  • Check the output pressure and the amperage draw of the compressor. The minimum output pressure (taken from the head going directly into a gauge – no tank) is 155p.s.i. The typical amperage draw for the compressor is 12-15 amps. If the output pressure is below 155 psi and the amperage draw is less than 15 amps you may be able to repair the unit using the Head kit (H00850HK) and piston Kit (H00850PK). If the output pressure is below 155p.s.i. and or the amperage draw is above 15 amps replace the compressor.

Compressor Troubleshooting

The following diagnostic questions may help in determining the cause for compressor failure and help to restore proper function of your system.

Does the compressor come on without using the horns?

Yes – Check for air leak preferably by dunking tank assembly in water. Repair any leaks found (i.e. fitting leaking, hose leak, tank leak, or solenoid leaking at outlet- clean solenoid.)

How much air pressure is in the tank?

Pressure switch should shut off compressor at 135 p.s.i. (+ / – 7 p.s.i.)

Use a tire gauge to verify the accuracy of gauge on the tank.

How long (in minutes) does the compressor run before shutting off?

Maximum run cycle is seven minutes of continuous run time. After 7 minutes the compressor must cool for a minimum of thirty minutes, depending on ambient temperature. It is best to allow the compressor to be cool to the touch before proceeding.

What proximity is the customer to a large body of water or to the coast?

Over time, high humidity levels affect the performance of the plunger and may accelerate the need to clean the solenoid. Common symptoms which will indicate cleaning is necessary are: No sound from horn (no air passing at all), horn does not shut off.

What is the voltage and amperage of the compressor (with vehicle running)?

There should be at least 12vdc, measured at the compressor while it is running.

The amperage should not be higher than 15 – 15.5 amps.

If compressor is not running, what is the voltage on both sides of the pressure switch (with vehicle running)?

There should be at least 12vdc, measured between the pressure switch terminals and ground.

What is the length of the run for the wires and what gauge wire is being used?

If the size (gauge) of the wire is not adequate for the length of the run, a drop in voltage may result, affecting the performance of the compressor.

Other considerations:

How often are the horns used?

Is the system being used to fill up tires?

For additional diagnostic help contact Hadley Warranty Center or submit a request via the Self-Service portal.

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