Pump Solutions Group Neptune Series 6000 dia-PUMP MODELS 6100 thru 6250 - Manual (Page 9)

9
4.0.2 The internal relief valve is designed to protect the pump itself should a discharge pressure
beyond the relief valve setting occur.
4.0.3 If a customer order specifies a relief valve setting above those indicated above, the specified
setting will be set at the factory. All pumps are tagged with the relief valve setting used by the
factory.
4.0.4 To protect the external piping system, it is recommended that a relief valve as manufactured by
Neptune Chemical or equal be placed in the discharge line of the pump. It is further
recommended that this relief valve be piped into return of the tank with clear PVC tubing so
that it can be determined if the solution is bypassing through the valve and returning to the
tank, indicating a line blockage.
4.0.5 Drawing on page16 illustrates the locations of the internal relief valve (#32, #33, #34, #35, #36,
#37 on Parts Drawing).
4.0.6 The drawing shows a passage connecting the hydraulic fluid reservoir with the hydraulic fluid
side of the diaphragm.
4.0.7 The passage is interrupted by the relief valve ball (FIG. #37 on Parts Drawing), which is
backed up by a relief valve spring (#35 on Parts Drawing).
4.0.8 If, during the pump operation, the pressure on the hydraulic fluid side of the pump exceeds the
set pressure of the internal relief valve, the ball is forced from its seat allowing the hydraulic
fluid to flow back to the reservoir.
4.0.9 To reset the relief valve to a higher pressure (the relief valve setting cannot be reduced
because of design considerations), instructions are as follows:
4.0.10 Connect a test set-up as shown in Figure 2 (Page 10)
NOTE : All parts must have a working pressure rating above the required set pressure.
4.0.11 Start and run the pump until all air is relieved from the discharge liquid (hand valve open).
4.0.12 Remove relief valve cap (#32 on Parts Drawing).
4.0.13 Close hand valve; pressure gauge should read between 250 and 4500 psi depending on pump
model.
4.0.14 Use 5/16” Allen wrench to adjust spring tension by turning relief valve adjusting screw
(#34 on Parts Drawing).
(1) To increase pressure, turn relief valve adjusting screw (#34 on Parts Drawing) in.
(2) To decrease pressure, turn relief valve adjusting screw (#34 on Parts Drawing) out.
4.0.15 After resetting or adjusting pressure, replace relief valve cap (#32 on Parts Drawing).
CAUTION
Never turn relief valve adjusting screw (# 34 on Parts Drawing.) completely in.
Do not attempt to set the internal relief valve more than 25% in excess of nameplate rating.