Fire Protection

Home > Blog > What To Do When Your Air Compressor Gets Wet

What To Do When Your Air Compressor Gets Wet

Your air supply for dry pipe sprinkler systems can be affected by water for a number of reasons: a storm, flood, back-flow from the system after a hydrostatic test, or leakage from resetting a dry pipe valve to name a few. Water on a fire protection air compressor can cause the unit to rust prematurely, create a dangerous electrical short, and even create internal damage to the unit depending on the amount of water introduced.

In order to keep your air compressor operational in the face of circumstances like these here are a few preventative methods to keep the compressor away from water, as well as some damage control that can be done if the unit is already wet.

Before Your Air Compressor Gets Wet – Preventative Measures

At installation, ensure that the riser mounted compressor is hung ABOVE the dry pipe valve. When a hydrostatic test is conducted, oftentimes leakage will occur both at the dry pipe valve itself and from drain points above it. Ensuring the compressor is mounted above those common leak points will remove them from the equation.

If you are using a tank mounted compressor, apply the same logic – do not install it directly below the dry pipe valve or drains.

*Photo of compressor hanging above the valve.

Close the Isolation Valve When Running Your Hydrostatic Test

Running a hydrostatic test without closing your isolation valve can flood your air compressor.

It sounds simple, but before running a hydrostatic test on a fire sprinkler system, ensure that the isolation valve on the air line between the compressor and the dry pipe valve is closed. Isolating the compressor from the system during testing will ensure there will be no immediate backflow into the air compressor. While a simple step, this is often overlooked and can cause premature failure of your compressor by allowing water into the air pump head.

*Pro Tip*: The correct positioning of piping drip legs will assist this. Consult our installation diagrams for correct position.

Before Opening That Isolation Valve…

Blow out the system. At the end of your hydrostatic test there’s likely water that’s settled against the back of your check valve. Before opening it up and exposing your compressor to that water backflow, perform a system blow out to remove that trapped water.

*Pro Tip*: Trapped water is the number one enemy of any dry system. It will rapidly increase the likelihood of corrosion which can lead to air leaks. Performing a system blow out after your annual hydrostatic test will not only protect your air compressor, but is also an inexpensive way to mitigate corrosion and future air leaks in any dry pipe sprinkler system.

So Your Air Compressor Is Wet. Time for Some Damage Control.

As described, there are many ways that your air compressor can become wet. In the event of a small amount of water getting on the motor or electrical components of the unit:

  1. Turn it off.
  2. Clean up the excess water.
  3. Restore power and observe the unit as much as possible to ensure consistent and correct operation. If the unit sparks or sounds like it is struggling to run, shut it off immediately at the disconnect switch and the electrical panel, then contact the manufacturer for the next steps.

NEVER stand in water while touching electrical panels. In the event your valve room floods, remove all water at your feet before handling the compressor’s connection.

When in doubt about the amount of water that the compressor encountered or just as a precaution a smart move is to take the unit to a warm and dry place, allow it to dry out, and then have it checked electrically for ground faults or shorted windings. Only when it is cleared should the unit be put back into service.

So Your Air Compressor Went for a Swim…

Wet Air Compressor, Flooded Crank Shaft
A rusted compressor sits with a flooded crank shaft since being left untreated after a flood.

If your fire sprinkler air supply is flooded or in some way completely consumed with water we highly recommend that you remove and replace the unit. While some people have had luck drying the unit out and starting it up again, this is not recommended.

Even in the event that the unit starts up again, there is no telling what internal damage has taken place. This can lead to an electrical fire or an unwanted system trip.

Remember that water and electricity are not friends. When water gets onto any piece of industrial duty electrically operating equipment, use EXTREME caution. As always, when in doubt, turn it off and call General Air Products technical support at 800-345-8207.