How to drain a pool installation ?


The Dualsun pool heating capability is designed to operate only during swimming season. While the Dualsun panel is capable of lengthening this season by several weeks, during the winter and in countries with a risk of frost we recommend draining the solar installation to avoid damaging it. The drainage period will vary depending on the geographic location of your installation; check the mean climatic data for your region to avoid frost.

A drainage kit is included in the system for installations located in zones with a risk of frost. It contains:

  • a solar aerator

  • PVC fittings including a shut-off valve and a ¾” threaded end to install a hose onto the drain valve


Recommended drainage period:

  • Drainage: end of October

  • Filling: end of April

When draining, the solar system must be switched off at the solar control unit.

The solar aerator is a diaphragm valve specifically designed for this application, and allows air to enter the circuit at the onset of a slight internal negative pressure (5 mbar). This occurs when the drain valve is open.


Step 1: Switch the regulation HND mode to OFF:

To do this, you must go to the regulator's installer menu by scrolling through the menu options with the top button. Once the display is no longer scrolling, the top button must be pressed for 5 seconds => the display changes, you are in the installer menu. Then you must continue to scroll through the options until you reach the HND parameter, once there, press the central button to modify it, switch it to OFF then press the central button again to validate. Do not touch anything, after one minute of inactivity, the regulation will return to the basic display. Be careful when putting it back into service (in the spring), it will have to be put back in AUTO and not in ON!

Step 2: Open the field outlet valve:

Depending on the configuration of your installation, it is possible that a drain valve has been installed at the exit of the fields: it should be accessible. All you have to do is open it, wait for all the water to run out, then close it to avoid any intrusion of external elements. If you do not have a drain valve, your installation is self-draining. So you don't have to do anything more! The panels will empty by gravity into the pool. Wintering is over!


When putting the system back into operation, check the position of the valves and set the control unit to Auto.

Some installations may have the panels at a height close to that of the pool. When the discharge of the panels is below the level of the pool, it may be necessary to manually drain the installation. In this case we recommend adding a manual drain valve to the installation.

To know more you can check the following article Is the Dualsun Spring panel drainback compatible?