The reference valve is simple diverter, allowing your system to be bypassed during priming or solvent changes. Users can operate pumps at any flow rate, without damage to columns. The valve can be added to any Waters model 510, 515, or 600 pump. Reference Valve. 1525 EF HPLC Pump; 1525 HPLC Pump, 510 HPLC Pump, 600 MultiSolvent Delivery System; 610 PowerLine Isocratic Pump.