A.O. Smith EQ 380 G manual Technical safety equipment, Gas control block, Thermal Reflux Safeguard

1.2 Technical safety equipment

Gas control block

The water heater has been fitted with a gas control block consisting of a thermo-electrical pilot flame safeguard, pilot flame pressure regulator, burner pressure regulator, a control thermostat (adjustable between 30°C and 71°C) and a safety thermostat (82°C). This gas control block with its simple and secure control respectively switches the gas supply to the main burner on or off.

This gas control block is suitable for gasses from the first, second and third gas family. The maximum inlet pressure is 50 mbar.

Drawing 2 - Gas control block with T.R.S.

Thermal Reflux Safeguard

The heater is fitted with a flue gas blowback safety device. The functioning of the safety device is based upon the principle of the Thermal Reflux Safeguard – TRS for short – shown in Fig.2.

This TRS can be recognized by the copper coloured spiral that is fitted to the lower edge of the draught diverter. The spiral is connected to a thermostat by means of a capillary tube. The wiring of the thermostat must be connected to the thermocouple circuit.

1)T.R.S. thermostat

2)Sensor T.R.S. thermostat

3)Thermocouple with built-in interrupter

4)Thermocouple

5)Gas control block

6)Reset button

7)Pilot burner

8)Temperature regulator knob

6