Instruction manual TWI 35-130 G/TWI 45-190 G 13
2.4.2 Security of the water temperature
The safety switch or ECO (Energy Cut-Off) switches off the device when the
water temperature exceeds 95 ºC. As soon as the temperature has suffi ciently
dropped, the ECO is reset automatically. Contact the installation engineer if the
ECO repeatedly switches off the device.
2.4.3 Gas control
The electronic control opens the gas control allowing supply of gas to the
burner. The gas control has two valves as a safety device. Both valves shut off
the gas supply.
2.4.4 Fan
The fan (10) ensures optimum air supply during the heat demand. In view
of safety, the fan makes sure that the combustion chamber is purged before
ignition takes place. This is called pre-purging.
2.4.5 Air pressure switch
The air pressure switch guarantees discharge of fl ue gasses and supply of
air during pre-purging and operation of the device. The air pressure switch is
typically open. When the pressure difference is suffi cient, the pressure switch
closes. If, however, a disturbance occurs, the pressure switch opens again and
the heating cycle is interrupted. The table gives the trip points for each device.
Remark
The trip point of the pressure switch cannot be adjusted.
Trip point of the pressure switch
2.4.6 Ionisation detection
The electronic control uses the hot surface igniter for fl ame detection by means
of ionisation detection. The electronic control closes the gas valve as soon as it
observes that there is no fl ame while gas is fl owing.
Device Pressure difference
TWI 35-130 700 Pa
TWI 45-190 370 Pa
