Installation Guide

Tilt

System

Tank

Valve

If the noise comes back, try the above procedure again another 2-3 times. Sometimes it takes several

tries to get rid of all the air in the system.

If the noise persists after a few days, that means there is air in your water source, or the current Check

Valve is resonating with your water pressure and pipes, creating the noise.

In this case, a new Check Valve will solve the problem. Contact APEC customer service for assistance.

* * * End Trouble-Shoot Guide * * *

Fig. 19

Step 1 Step 2 Step 3

12) RO Makes Humming Noise

When RO makes a humming noise, most likely it’s caused by air bubbles being trapped in the “Check

Valve” during installation. See check valve on Fig. 18, point E (Page 29).

To purge air from the check valve, do as follows:

Step 1: Close the tank’s valve.

Step 2: Tilt the RO system to the right. Put something under the 3rd filter housing to keep RO tilted. This

helps dislodge the air bubbles from the Check Valve.

Step 3: Turn on the RO spigot. Let pure water flow throuh the spigot for about 1 minute. This forces the

air to flow directly out to the spigot, bypassing the tank.

Step 4: Turn off the spigot. Wait for about 10 seconds. Repeat Step 3 again. Do that 3-4 times. If you

see air sputtering out of the spigot, repeat Step-3 until pure water can flow smoothly from the spigot, or

until the noise goes away.

Step 5: When the noise is gone, open the tank valve, let RO run as usual.