| 摘要 |
PURPOSE:To make appropriate display on the outside by detecting acculately a residual hot water quantity without complicating an operation, by so constituting that a device deciding the residual hot water quantity automatically is provided so as to enable to display appropriately based on the decision. CONSTITUTION:A measured voltage level Vm is checked at a step 28 if it satisfies ¦VA¦<=¦Vm¦ as compared with a predetermined value VA, if so it is decided at a step 31 that a residual hot water quantity is ''much''. When a check at the step 29 reveals that the voltage level Vm does not satisfies ¦VA¦<=¦Vm¦, the voltage level Vm is checked at a step 29 if it satisfies ¦VB¦<=¦Vm¦, if so it is decided at a step 32 that the residual hot water quantity is ''medium''. When a check at the step 29 reveals that the voltage level Vm does not satisfies ¦VB¦<=¦Vm¦, it is checked at a step 30 further that if the voltage level Vm satisfies ¦Vc¦<=¦Vm¦, if so it is decided at a step 33 that the residual hot water quantity is ''little''. When a check at the step 30 reveals that the voltage level Vm does not satisfies ¦Vc¦<=¦Vm¦, it is decided at a step 34 that the residual hot water quantity is nil, and then deciding action of the residual hot water quantity is completed. Respective decided results are applied to a display part 20 through an output circuit 17, through which display units 21, 22, 23 are made to display. |
