Possible causes of the following malfunctions in the operation of the high-pressure sprayer:
a) if liquid drops are leaking from the spray gun, means, that the paint needle is loose or that a foreign body has entered the nozzle, which caused it to leak;
b) if air escapes from the piston, the stuffing box is too tight; if it goes further after tightening the gland, the gasket is faulty or missing;
c) the split spray pattern indicates this, The material is being fed in too thin or the atomization pressure is set too high;
d) the oval shape of the spray jet is then formed, when the air pipe or component is dirty (finger) handing the paint;
e) if material in the hopper foams, means, that the air tube is clogged or that the air nozzle is not fully tightened.

In a pressure sprayer, the material to be sprayed is placed under pressure in a tank 1-2 bars, pressing material into the gun. Then, material being sprayed, similar to high pressure spraying, it is finely atomized under the action of compressed air.

Advantages of spraying from a pressurized tank.
As the flow rate of the material is greater in this case than in a spraying device with a flow-through tank or a suction tank, also the area coverage of the spray can be much higher. Otherwise, with less fog formation, better spray quality is achieved.

Advantages and disadvantages of airless spraying device?
Advantages:
1. When using an airless type device, a high surface efficiency of spraying is obtained.
2. Materials to be sprayed need not be very thinned, therefore they cover painted surfaces well.
3. Fog formation is less intense. Because the material does not have to be diluted that much, contains less solvents, which is of great importance for the protection of the environment.

Defects:
1. The device is quite expensive. In return for higher purchase costs, high operating efficiency is achieved.
2. The quality of the paint coating applied using an airless device is worse than with high-pressure spraying. Water stains are easy to form, especially when painting elements with complex profiles.

The causes of the following airless equipment malfunctions:

a) no shower – In an electrically driven device, the current network has insufficient protection. In a combustion engine, the cause is a malfunction of the internal combustion engine (e.g. spark plugs are dirty or the fuel line is clogged).

b) no suction of spray material – If the machine does not suck up the material, means, that the suction filter is clogged or not completely submerged in material. It may also be because the oil level is too low.

c) when spraying, the pressure decreases rapidly – If the pressure decreases rapidly during spraying, the nozzle is too large or the material consistency is not selected correctly. In the case of a pneumatic airless unit, the cause may also be insufficient compressor capacity.

d) the material feed pump reduces capacity and also works with the shut-off valve closed – If pump capacity decreases, and the pump continues to run after the shut-off valve is closed, the cause is damage to the device. There may be a leak in the air supply system, defective piston rod or worn valves and seals.

e) in a device of pneumatic type, the pump does not work – If the pump in the pneumatic device does not work, the reasons can be very different, e.g, air supply hose not included, compressor not turned on; material lines may be clogged, Clogged shut-off valve, filter or gun hose. Also possible, that the controls have been locked.