subroutine Pump_OffMode_Solver(Pump_No)
    
    use SimulationVariables
    
    IMPLICIT NONE
    INTEGER :: Pump_No
    
    
    
    data%State%Pump(Pump_No)%N_new = 0.d0
    
    !========================== Pump Rate limit ==========================
    if (((data%State%Pump(Pump_No)%N_new-data%State%Pump(Pump_No)%N_old)/data%State%Pump(Pump_No)%time_step)>data%State%Pump(Pump_No)%RateChange) then
        data%State%Pump(Pump_No)%Speed =(data%State%Pump(Pump_No)%RateChange*data%State%Pump(Pump_No)%time_step)+data%State%Pump(Pump_No)%N_old
    else if (((data%State%Pump(Pump_No)%N_old-data%State%Pump(Pump_No)%N_new)/data%State%Pump(Pump_No)%time_step)>data%State%Pump(Pump_No)%RateChange) then
        data%State%Pump(Pump_No)%Speed = (-data%State%Pump(Pump_No)%RateChange*data%State%Pump(Pump_No)%time_step)+data%State%Pump(Pump_No)%N_old
    else
        data%State%Pump(Pump_No)%Speed = data%State%Pump(Pump_No)%N_new
    end if
    !=======================================================================
         
        
    data%State%Pump(Pump_No)%Flow_Rate = data%State%Pump(Pump_No)%FlowRatePerSTK*4118.d0*0.01d0*(data%State%Pump(Pump_No)%Speed/data%State%Pump(Pump_No)%Trans_Ratio)                                 ![gpm]
    data%State%Pump(Pump_No)%HorsePower = ((data%State%Pump(Pump_No)%Flow_Rate/0.01d0)*data%State%Pump(Pump_No)%StandPipe_Pressure)/(168067.d0*data%State%Pump(Pump_No)%Mech_Efficiency)              ![HHP]
    !data%State%Pump(Pump_No)%Max_Horsepower = ((data%State%Pump(Pump_No)%Flow_Rate/0.01d0)*data%State%Pump(Pump_No)%Max_Pressure)/(168067.d0*data%State%Pump(Pump_No)%Mech_Efficiency)               ![HHP]
    data%State%Pump(Pump_No)%Max_Horsepower = (data%State%Pump(Pump_No)%Flow_Rate*data%State%Pump(Pump_No)%Max_Pressure)/(1714.d0*data%State%Pump(Pump_No)%Mech_Efficiency)
    if ( data%State%Pump(Pump_No)%StandPipe_Pressure>data%State%Pump(Pump_No)%Max_Pressure ) then   ! in shart check shavad
    !if ( (data%State%Pump(Pump_No)%StandPipe_Pressure*data%State%Pump(Pump_No)%Flow_Rate)>(1714.d0*data%State%Pump(Pump_No)%Max_Horsepower*data%State%Pump(Pump_No)%Mech_Efficiency) ) then
        data%State%Pump(Pump_No)%Flow_Rate = (1714.d0*data%State%Pump(Pump_No)%Mech_Efficiency*data%State%Pump(Pump_No)%Max_Horsepower)/data%State%Pump(Pump_No)%StandPipe_Pressure                   ![gpm]
        data%State%Pump(Pump_No)%Speed     = ( data%State%Pump(Pump_No)%Flow_Rate/(data%State%Pump(Pump_No)%FlowRatePerSTK*4118.d0*0.01d0) )*data%State%Pump(Pump_No)%Trans_Ratio                     ![rpm]
    end if
        
    data%State%Pump(Pump_No)%SoundSPM = INT(data%State%Pump(Pump_No)%Speed/data%State%Pump(Pump_No)%Trans_Ratio)
        
    If (data%State%Pump(Pump_No)%Flow_Rate>0.d0) Then
        data%State%Pump(Pump_No)%Open_Close = 1
    Else
        data%State%Pump(Pump_No)%Open_Close = 0
    End if
        
   
    
        
       
        
end subroutine Pump_OffMode_Solver