How to start a gas double-circuit boiler after an emergency stop?

Good day. I am addressing you with such a problem. In our house there is a double-circuit boiler with a coaxial system. During the repair of the heating system, all the water was drained. At that moment, the wife decided to wash the dishes and turned on the hot water tap. The boiler, naturally, reacted, and as a result an emergency shutdown of the device occurred. Alarm sensor has triggered. When the pipe repair was completed and the system was filled with water, the boiler could not be started. The emergency light was on and the heating system did not start. We cannot invite experts, since the nearest service is 100 km away. Help start the boiler correctly. The brand of the boiler is Viessmann.

In order to start the heating system after an emergency stop of the gas boiler, it is necessary to fill the radiators and pipes with water. Before that, look at the boiler’s technical data sheet about the minimum and maximum working pressure of the water in the system, and fill in the border of these numbers. Check the pressure level on the sensor, which is installed on the front panel of the device (it can be from the bottom, from the side, depending on the brand).

Next, check the gas connection. Whether all connecting hoses are in place, the gas supply tap is not blocked.

If everything is in order, press the “network” button on the boiler to start the system.

Unlocking the emergency state of the boiler

1. Using the handle of the heating temperature controller on the boiler instrument panel, set the temperature to maximum.
2. Then sharply turn off the temperature controller to zero.
3. We repeat the procedure 2-3 times, turning the sensor to the maximum, then to the minimum.
4. We leave the regulator in position at maximum temperature and expect automatic unlocking of the boiler. The system should start automatically.
5. We are waiting for the emergency stop lamp to go out.
6. After such manipulations, we set the regulator to the desired temperature mode.

Unlock completed.

Additional recovery steps

Be sure to expand the heating system, i.e. bleed air from radiators in all points of the house where you have cranes. Do not forget about the heated towel rail (if there is a tap on it).

On the boiler, check the water pressure in the system again so that it is at least 1.5 bar at the beginning of operation. This is the minimum working pressure in all gas boilers while the water in the pipes is still cold. As soon as the fluid heats up, the pressure becomes higher. It is desirable that it does not exceed 2.5 bar. Too much pressure is harmful to the connecting elements of the system (gaskets, cuffs, etc.), which can simply be broken by the force of water.If the sensor has shown above the maximum figure in your data sheet, drain some water from the pipes and check the pressure again.

On this, your actions to restore the gas boiler are completed.