Evaporative coolers work by evaporation, so their performance will be determined by the outside temperature and the relative humidity (RH). Its operation and performance are DIFFERENT than an air conditioner. The following table shows the performance of a Neil Evaporative Cooler given the conditions of relative humidity and ambient temperature.

You can measure the air outlet temperature of the Neil Evaporative Cooler and compare it with the following table to determine if your Neil device is working properly.

Basic technical verification (this simple procedure solves 85% of the problems)

The Neil Evaporative Cooler has 3 fundamental components. If your Neil device is not cooling properly, it is highly likely that one of these 3 items is not working properly and requires maintenance.

Water Pump System

Humidifier System

Wet Filter

Start with basic maintenance….

1. Make sure that the water tank is full of water.

2. Remove the cover of the evaporative cooler, in case you notice that the irrigation tube is clamped on the cover, remove it and rest it on the wet filter, ensuring that it remains connected to the humidifier pump.

3. Once this is done, you will be able to see if all the evaporative cooler systems are working properly,

Wet Filter Review

3. Visually check the condition of the wet filter. A dirty or crushed filter lowers the performance of the evaporative cooler. The filter is recommended to be cleaned after the first season of use and replaced after the second season*.

* A season is a summer of use.

Dirty Filter

Crushed Filter

OK Filter

How to replace a Wet Filter?


Premium 700

Humidifier Pump Review

1. Remove the sensors from the pre-cooling chamber and put them together. When the sensors make contact, the evaporative cooler interprets that there is water in the pre-cooling chamber.

Sensors together

2.  Turn on the evaporative cooler and set the fan to minimum speed.

3. Every 20 to 45 seconds (depending on the water pump model) you should listen* to the humidifier pump and watch as water falls through the holes in the irrigation tube and wets the filter.

*If your Neil device has a brushless water pump, you may not be able to hear it.

4. Once it has been confirmed that water is coming out of the irrigation tube and that the filter is wetting properly, it means that the Humidifier Pump is working properly.

5. In case the water is NOT coming out of the irrigation tube, the pump is probably burned up and must be replaced.

IMPORTANT: Bear in mind that electronic (brushless) pumps are very quiet and can sometimes become clogged with dirt. If your evaporative cooler has electronic pumps (Camper- Slim Full – Premium 700 model 2020 onwards) we recommend that you remove it from the evaporative cooler, disassemble, clean and replace it.

How do I replace the Humidifier pump?

Master - Slim Full - Camper​
(traditional pump)

(brushless pump)

Fusion - Agro - Premium 700/900
(traditional pump)

6. In case you hear the Pump and the water is NOT coming out of the holes in the irrigation tube:

  • Check that the holes in the irrigation tube are unobstructed.
  • Check that the «T» is not obstructed.
  • Make sure that the pump in addition to making noise is sending water.

Spray Tube


Water Tank Pump Review:

1. Remove the sensors from the pre-cooling chamber and keep them separated. When the sensors do NOT make contact, the evaporative cooler interprets that there is NO water in the pre-cooling chamber and requests water from the external tank.

Separate Sensors

2. Disconnect the charging hose and place it in an empty container so that you can measure how much water is entering in the pre-cooling chamber.

3. Turn on the evaporative cooler and set the fan to the lowest power.

A. You should be able to see the water coming out of the charging hose for 12 to 25 seconds (depending on the water pump). If you use traditional pumps you will also hear them, while if you use brushless pumps you may not hear them.

B. In case NO water is coming out:

  • The water pump is probably burned up, in that case it must be replaced. (Important: In case your evaporative cooler has brushless pumps, it is recommended to disassemble the pump and clean it. It is likely that once cleaned it will work correctly again)
  • It may happen that the hose that carries water from the tank to the evaporative cooler is strangled. We recommend blowing on one end to be sure there are no obstructions.

C. In case of  water coming out, but the quantity is less than a can of soda (approx.):

  • Check that the hose that goes from the water tank to the evaporative cooler is NOT strangled.
  • If the horizontal distance between the water tank and the evaporative cooler is long (for example in motorhomes) it may be necessary to increase the power of the tank´s water pump. You can see how it is done in the following video: Link to Video 

Evaporative cooler does NOT turn on

1- Connection of the evaporative cooler to the battery

Check that the connection of the wires of the evaporative cooler to the vehicle´s battery are correctly placed.  It is very important that these are NOT loose and that these are not sulfated. If these are loose, you must adjust them and if they are sulfated, you must remove them, clean them and reconnect them.



2- State of the evaporativoe cooler´s fuse

The evaporative cooler has a fuse that is placed near the battery, it is necessary to check it to make sure that it is NOT blown. If it is blown, replace it with a 15 Amp fuse.

OK Fuse

Blown fuse

Where is the fuse holder located?

3- Command connection (upper)

Movement and vibrations after several years of use can cause the evaporative cooler to disconnect from the installation connectors. It is necessary to check at the back of the evaporative cooler or inside the evaporative cooler if it has an indoor connection.

Connection tab location

Bad connection

OK Connection

4- Command (burned up)

It is very difficult for the Command to burn up but it could happen. Perform a visual inspection to identify signs that the command is burned up.

Command burned up and / or sulfated

If the command is burned up, you must request a new command so the evaporative cooler works correctly again, once the problem that caused the failure has been corrected.

-The controller remains illuminated after the climate control is turned off (Only in Premium Control Panel)

    • This is the default configuration to the controlller, if you want the controlller to turn off completely you must, with the controlller off, press the «-» (minus) key several times. In this way, the lighting will be lowered.

-The light is blinking on the control panel («No water» signal) but the water tank is full.

  • The water tank´s pump is burned up or is not working properly. It is recommended to replace it.
  • The sensors are sulfated, it is recommended to remove them, sand them with a fine sandpaper and replace them.
  • There is a problem with the charging hose or the wires that reach the pump. It is recommended to check the wiring from the evaporative cooler to the water tank, making sure that the hose is not blocked and the electrical terminals are correctly connected.

-The fan only speeds up and down

    • The electrical connection from the controlller to the motor may be loose. It is recommended to open the cover and check that the electrical connectors are correctly positioned.
    • The engine may be failing. After several years of use and even more so if water gets inside the evaporative cooler, the motor coals deteriorate. It is recommended to replace the motor.
    • There may be an electrical problem in the battery that prevents the motor from working properly. It is recommended to check the battery.


Wet Filter

Traditional Water Pump

Brushless Water Pump

Water falls inside

It is highly unlikely that water will enter the vehicle, however it can rarely happen. The causes are multiple and most can be solved very simply by the user.

Possible causes

The water tank is very close to the evaporative cooler.

  • If the vertical distance between the evaporative cooler and the top of the water tank is less than 35 in (80 cm), it is likely that as the vehicle moves, more water will enter the evaporative cooler than it should.

Solution: The water tank must be located at least 35 in (80 cm) below the evaporative cooler. If this is not possible, you will need to lower the power of the tank water pump.

Vertical distance between the evaporative cooler and the water tank

How to lower the power of the tank pump?

There is some problem in the Connection tab.

    • In the event that a pin of the installation connector is wrong connected, it is likely that the evaporative cooler may not be working properly. Because of this problem, the tank pump could work continuously, which can cause water to enter the vehicle.
    • There may be some inconvenience in the connection between the command and the internal connection tab, we recommend checking that the tab is correct. See Electrical Connection Diagram.
    • It is important that the connectors are as shown in the following image.

The wet filter is very dirty

      • If the wet filter is full of dirt, the wood chips become waterproof and crushed, so the water that falls from the sprayer is sucked into the fan and enters the fan.

The water tank pump has a lot of power.

    • If the water tank is close to the evaporative cooler, it is possible that the tank pump is sending too much water to the cooler each time it is required.
    • Solution (only in Premium Control Panel): You can modify the power of the external tank pump, you must lower it to send less water to the evaporative cooler. You can see how to configure the external pump in the following video:

How to lower the power of the tank pump?

The irrigation tube is incorrectly positioned

  • If the irrigation tube is not correctly positioned, some of the holes may be facing the motor and wetting it each time it irrigates.
  • Solution: check that the irrigation tube is correctly positioned.

Fusion – Premium 700/900 – Agro

Slim Full – Camper

Slim model 2