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SPRING LOADED BACK PRESSURE VALVE
User manual
DAN-20064957
9
Corrective maintenance
9.1
Control valve troubleshooting
9.2
Verify the return to operational condition
User manual
44
www.Daniel.com
Use the table below to troubleshoot the control valve. Contact the nearest Flow Lifecycle
Services center for assistance with repairs of Daniel products. It is important that servicing
be performed by trained and qualified service personnel.
Table 9-1: Troubleshooting issues of 707 Backpressure Control Valve
Condition
Probable cause
Valve will not open
Upstream valve is
closed
Pump is not operating
Downstream valve is
closed
Insufficient pressure
Swollen O-rings
Valve opens too slowly Swollen O-rings
Valve will not close off
Foreign material in
tightly
main valve piston seat
Swollen O-rings
Piston or seat O-ring
cut or defective
(1)
Refer to
Mechanical disassembly
Once corrective maintenance has taken place, verify that the control valve is working
properly by following the steps below.
Procedure
1. Inspect all bolts used to secure the control valve in-line to ensure that proper
mounting procedures have been followed and that flange connections are leak-
free.
2. Evaluate the system setup to ensure that all components are in the correct
operating sequence.
(1)
Correction
Open upstream valve.
Start pump and check for cavitation.
Open downstream valve. (Check coupler on
bottom loading units and internal valve in
truck.)
Check pump. Check bypass and strainer located
in line.
Disassemble valve and replace O-rings. Check
compatibility of O-rings with product.
Disassemble valve and replace O-rings. Check
compatibility of O-rings with product.
Disassemble valve and inspect piston.
Disassemble valve and replace O-rings. Check
compatibility of O-rings with product.
Disassemble valve and replace if necessary.
procedures.
Corrective maintenance
August 2019
55
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