Gas fired water heater regulator - has manual switch for adjusting regulator for three different rating values

摘要

The gas fired boiler has a gas flow adjuster with a regulator actuated by an electrical signal. Between the regulator (23) and the adjuster (12) is fitted a hand switch (28). The latter connects the adjuster in a first switching position with the regulator. In a second position, the switch connects the adjuster to the contactor (31) which carries a signal for nominal rating. In a third position the switch delivers a signal at the potential corresponding to the lower threshold value of the rating to a contactor (32).