The first thing we need to control is if the current goes up to the solar heater. This is done with a test screwdriver or a multimeter. There are three thick wires connected to the solar: blue neutral / brown or black phase / two-tone yellow green ground. With the switch open from the panel, we test with the test screwdriver in phase if there is current.


The current is an invisible dangerous friend If the current comes on, then we have to check the thermostat for its thermal. Thermal is a very small button that is different for each type of thermostat.

In round, it is next to the button that adjusts the temperature. On square thermostats is a very small slit. This is done with the tip of a pen, we will hear a very low CLICK sound. If after pressing of the heat pump it does not work again, then we have to check the resistance. This is done with a multimeter by putting its edges on the resistance pins. CAUTION we previously switch of the power. If the multimeter does not close a circuit in Ω then the resistance is burnt. Replacing the resistance is easy by pulling the thermostat out. Unscrew the 8 screws and remove them.


In the same way we place the new resistance with new rubber.


In this case there is a leakage of current. Disconnect the cable from the solar panel. CAUTION switch of the power supply first. After disconnecting the cable, be careful that the bare wires do not touch anywhere or turn on the power supply switch. If the relay does not drop, the resistance is short-circuited. But if it falls, then the leak is on the cable. The tips are free.


The first thing we have to do is to blow air from the blow off valve in the boiler. Where the radiator lines are connected. at the top of the radiator there is a small screw. She must always be relaxed to leave the air. Unscrew this screw and unscrew it with a pin in the hole until the water comes in. Then place the screw without tightening it. If the water does not come, we need to lift the radiator pressure from the automatic filling. The automatic filling must be adjusted every 10 meters and 1 bar from the point where the boiler is up to the solar system.

Automatic filling gives us more pressure when screwed in and falls when unscrewed. WARNING we do not screw it too much because the pressure is slowly rising. If the solar panel brings warm water from the radiator, then you need to raise the circulator thermostat to 55 degrees. The thermostat of the circulator is installed on the central tube (it is in contact).


First we have to check if the circuit is filled (in closed circuits) Closed circuits are the ones that get liquids. At the top of the cauldron there are 1 or 2 tubing in which a bubble or a blow off valve is screwed. Unscrew the lock if it has 1 tube. When it has 2 tubes, we also unscrew the bubble. We get 2 liters of antifreeze from the gas station for minus -32 / 50 degrees. We fill it from the one of the two tubes. If the antifreeze does not overflow the tube, until it is overflowing, fill with water.This ratio is for minus -14 degrees Celsius, for lower temperatures we put 3-4 liters.

If the problem persist (does not heat with the sun) when the circuit is filled, we need to drain the circuit from the lowest point of the solar (from the collectors) by unscrewing the fittings. You will unscrew the blow off valve and the bubble (if there is one in the top of the cauldron) and with a hose you will drain the circuit dry by rinsing the entire system. After rinsing the circuit, screw the unscrewed connection at the bottom of the collectors and re-fill the circuit. CAUTION: When filling the circuit from scratch we must first put 5-6 liters of water after the antifreeze. And the rest until the water is overflowing.


In this case, unfortunately there is nothing we can do. We have to change the boiler. Unless we are lucky and the leak is from the resistance flange.

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