Figure 3 step A shows air from the compressor enters the mechanical unloader valve through the inlet, travels through the unloader valve chamber to the non-return valve. Mechanical vs solenoid unloader valves Mechanical Electrical Adjustment Can be manually adjusted Adjusted at the pressure switch or timer Timer Cannot be operated with a timer Can be operated with a timer Position Can be installed in any position Should be installed upright or with a maximum deflection of 90° Obstructions Not sensitive to dirt More sensitive to dirt then a mechanical valve Application A mechanical unloader valve is commonly used in smaller compressors In heavier compressors the unloader valve used is typically an indirect solenoid valve. A malfunction of an air compressor unloader valve can cause leaks if it does not close properly, and even the compressor motor could not start if the valve does not open correctly.
An unloader valve malfunction is one of the more common air compressor issues. If you own a smaller reciprocating air compressor, you’ll likely find the unloader valve mounted on or inside the pressure switch. A larger air compressor often features a more sizeable unloader valve controlled by air pressure emanating from a smaller pilot valve.
Your reciprocating piston compressor will have a smooth start up, thanks to the unloader valve. The air compressor unloader is valve is a small, but important, part of the reciprocating piston compressor. Big unloader valve which is controlled by a small pilot unloading valve.
The following blog post will help you understand the piloted unloader valve by pointing out its components, explaining how it works and describing the adjustment process. The diagram below shows the components of our most common piloted unloader valve, part number 131B. How It Works. Piloted unloader valves combine a pilot valve and an unloader valve to run an air compressor continuously.
The air compressor unloader valve provides a critical function in preparing your air compressor to restart. A failed air compressor unloader valve is one of the most common reasons why your air compressor cannot restart after you have used air from the compressor tank. What the unloader valve does is that is responds to the compressor pressure switch turning the power off to the motor and allows any air that may be trapped over the piston, or pistons on a multi-cylinder air compressor, to vent to atmosphere, removing any load that the trapped air may have created over the cylinder piston.
Gas air compressor unloader valves are one of the numerous small, common and essential parts of an air compressor and the whole pressure maintenance process. The air compressor unloader check valve keeps the entire tank from draining and has a pipe running to the unloader valve. The air evacuating from the unloader valve does not stop the unloader valve from continuing leaking air after the compressor is stopped.
So much additional load could be added to the compressor motor that the motor cannot start against the load, and you may get a humming compressor motor or your motor could overheat and shut off on thermal overload. For sure, your compressor won’t be pumping air if the compressor motor cannot start. A compressor with this type of unloader typically has a pressure switch that is inserted into the tank under the compressor cover, and that style of switch has no place to connect an unloader valve. On these types of air compressors the unloader valve is also now known as a throttle valve.
what is air compressor unloader valve Related Question:
How do you know if your air compressor unloader is bad?
You can have two problems. Air leaking from an “unloader” valve on the pressure switch continuously (after the motor shuts off) is an indication of a leaking tank check valve, not a bad pressure switch. Air leaking from the unloader while the motor is running is an indication of a bad unloader valve.
How does an unloader valve work?
A trapped pressure unloader is a simple valve with a spring mechanism mounted in a Brass body. There is A channel within the body that gives water access to the back of a piston. When the trigger is released the pressure against the piston increases and pushes the spring open to allow the water to pass into the bypass.
How do I know if my unloader valve is bad?
Water leaks and inconsistent behavior are also signs of a potential failure in the near future. González: The typical signal when there is an unloader malfunction is a reduction of flow through the nozzle, which results in pressure loss. Dean: Typical symptom of an unloader failure is a sudden smooth pressure loss.
What is compressor loading and unloading?
When the compressor runs ‘loaded’, it is actually compressing air and pumping it into the system. When the upper setpoint is reached, the compressor switches back to ‘unload’. When the compressor runs ‘unloaded’, it is still running, but it is not compressing any air.
Where is unloader valve located?
Where Is the Unloader Valve Located? If you own a smaller reciprocating air compressor, you’ll likely find the unloader valve mounted on or inside the pressure switch. When the switch shuts the compressor off, it actuates the valve.
What is the difference between a regular relief valve and an unloading valve?
The relief valve protects the low-volume/high-pressure pump from pressure above 3000 psi. The unloading valve is set at 500 psi to divert flow from the high-volume/low-pressure pump to tank when system pressure climbs above this setting.
What is compressor unloading?
Unloading in a compressor is done to reduce the starting load and high starting torques. This is done by energizing a solenoid valve which in turns opens the outlet of compressor to atmospheric pressure and hence the only work done by compressor is to overcome friction.
Are all air compressor check valves the same?
There are so many reasons why air compressor check valves are used on air compressors. And, there are sometimes up to 5 check valves on a single compressor. It all depends on the compressor type, size and make/model of course. As said before, check valves allow the air to flow through in only one direction.
What happens if unloader valve is bad?
A failed unloader valve can cause high pressure at the nozzle. The unloader valve recirculates water to the pump inlet when the pump is running but the spray wand isn’t in use.
Why does my pressure washer keep surging?
Surging occurs when the pressure is fine and then weakens. It is caused when the flow rate for the pump cannot be supported by the water supply. Problems can mount from there so it is important that it is dealt with as soon as possible.
Why does my pressure washer dies when trigger released?
If a pressure washer stalls when the trigger is released, this usually indicates a fault in the unloader valve. It is a simple process to remove and replace the unloader.
Can you adjust an unloader valve?
Now while the gun is engaged you can adjust the pressure by turning the adjusting knob between the two nuts and the nylock on top. If you adjust the unloader without the gun engaged, when you do engage the trigger parts in the unloader move rather violently and could damage the unloader.
What is a unloader on a pressure pump?
The unloader diverts the flow of water from the outlet side of the pump back to the inlet side, causing water to flow in a loop back to the pump under virtually no pressure rather than to the nozzle under operating pressure.
How do I lower my psi with a pressure washer?
To reduce the impact pressure, simply step back from the area being cleaned. Some gas pressure washers have a pressure regulator on the pump. You simply turn the dial to increase or decrease the pressure. Others have a regulator on the spray wand, similar to the Vario wand on our electric power washer.
