Pump Solutions Group Neptune Series 600 dia-PUMP MODELS 610 thru 647 - Manual (Page 9)

3.0 DISCHARGE PIPING
3.0.1 It is recommended that the “dia-PUMP” operate against a minimum discharge pressure of 50 psig.
3.0.2 All Neptune Series 600 “dia-Pumps” are supplied with an internally pre-set relief valve. This relief valve is set
approximately 25% above the actual rated discharge pressure of the pump and is designed to protect the pump
should a discharge pressure beyond the rated limit of the pump occur.
3.0.3 To protect the piping system, it is recommended that an external relief valve as manufactured by Neptune Chemical
Pump Company, or equal, be place in the discharge line of the pump.
3.0.4 Discharge piping should equal discharge port size.
4.0 ADJUSTMENT OF INTERNAL RELIEF VALVE
4.0.1 All Neptune Series 600 “dia-Pumps” are supplied with an internally pre-set relief valve. The internal relief valve is set
as follows:
INTERNAL RELIEF VALVE SETTINGS (PSI)
Model 1/2H/P 3/4 H/P 1 H/P 1-1/2 HP 2 HP
610 1500 2500 3150 4375 ----
615 1500 2500 3150 4375 ----
620 ---- 625 750 1000 1500
625 ---- 625 750 1000 1500
635 ---- 300 350 550 750
637 ---- 300 350 550 750
637 PVC ---- 250 ---- ---- ----
647 ---- ---- ---- ---- 300
647 PVC ---- ---- ---- ---- 250
The internal relief valve is designed to protect the pump itself should a discharge pressure beyond the relief valve
setting occur.
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.
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.
Drawing on page 18 illustrates the locations of the internal relief valve for Models 610 and 615 (FIG. #1435, #1411,
#0145, #0119, #0146, #0120).
Drawing on page 20 illustrates the locations of the internal relief valve for Models 620 and 625 (FIG. #2335, #2311,
#0145, #0119, #0146, #0120).
Drawing on page 22 illustrates the locations of the internal relief valve for Models 635 and 637 (FIG. #3235, #3211,
#0145, #0119, #0146, #0120).
Drawing on page 24 illustrates the locations of the internal relief valve for Models 647 (FIG. #3235, #3211, #0145,
#0119, #0146, #0120).
The drawing shows a passage connecting the hydraulic fluid reservoir with the hydraulic fluid side of the diaphragm.
The passage is interrupted by the relief valve ball (FIG. #1435, #2335, #3235) which is backed up by a relief valve
spring (FIG #0146).
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 seal allowing the hydraulic fluid to flow back tot he reservoir.
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