The solar heater consists of:

• A solar panel that warms up a water-antifreeze mixture in a closed circuit
• A heat exchanger where the warm water-antifreeze mixture from the closed circuit warms up the water used in the apartment

In theory:

The solar collector and the outside of the storage tank are the closed circuit, the warm water we use in the apartment is cold water warmed up by a heat exchanger located within the storage tank.

In practice:

The roof setup:

There’s an array of solar heaters on the sun terrace. Determine which is yours (ours happens to be left, the downstairs neighbor is on the right).

The fittings for maintenance are on the left:

Upper:

Lower:

Check:

• Open or remove the upper tap
• Water should come out
• If so: ok
• If no water emerges: the closed circuit must be topped up

Topping up:

• Close the small tap on the bottom assembly
• Remove the cap from the bottom assembly
• Hook up your garden hose to the bottom assembly
• Open the tap to your garden hose
• Open the tap on the bottom assembly
• Wait for water to emerge from the top assembly, let it run a short while to get rid of air bubbles
• Close the top assembly
• Close the tap on the bottom assembly
• Close the tap to the garden hose
• Remove the garden hose
• Reinstall the cap on the bottom assembly

That’s all there is to it!

Antifreeze:

The closed circuit should contain a mix of water and antifreeze, partly to avoid freezing but mainly to avoid corrosion. This is shown by the color of the water emerging from the top assembly (blueish, greenish, or yellowish) but you can also carefully taste a droplet.

No color and no taste implies no or low level of antifreeze. This needs to be fixed by the plumber.