DSL101NR Normally Open Valve Failure Root Cause Isolation

 

When this normally-open pilot-operated valve fails to close upon de-energization, meaning the expected closing action simply doesn't occur, distinguishing between spool contamination sticking versus pilot circuit blockage requires checking a specific measurement point that quickly differentiates these two mechanically distinct failure paths.

 

Spool sticking directly within the main valve body, from contamination lodging within the spool-to-bore clearance, would occur regardless of whether the pilot control signal itself is functioning correctly, meaning pilot pressure delivery would show normal expected value even while the main valve fails to respond properly to that correctly-delivered pilot signal.

 

Pilot circuit blockage, preventing pilot oil from reaching the main valve actuation mechanism at all, represents a genuinely different failure location, where the main valve spool itself might be perfectly free and capable of moving, but simply never receives the pilot pressure signal needed to actually drive that movement.

 

Measuring pilot pressure directly at the pilot circuit, using a pressure gauge connected at an appropriate pilot line test point if available, gives immediate differentiating evidence between these two possibilities. Normal expected pilot pressure reading, despite main valve failing to respond, strongly points toward main spool sticking as the actual fault location, since correct pilot signal is confirmed present but not producing expected main valve response. Abnormally low or absent pilot pressure reading instead points toward pilot circuit blockage as the explanation, confirming the pilot signal itself isn't reaching the main valve mechanism properly in the first place.

 

This pilot pressure check offers genuinely quick field localization compared to more involved disassembly investigation, letting maintenance personnel focus subsequent repair effort specifically on whichever component — main spool or pilot circuit — the pressure measurement evidence actually points toward as the real fault location.

 

 

As a manufacturer of industrial products with a long history, YOYIK not only maintains a leading position in technology, but also pursues excellence in management philosophy. The company provides diversified products including turbine accessories, generator cover plastic seals, etc., serving a wide range of industrial fields. With fair prices and excellent quality, YOYIK has established a solid market position and good customer reputation worldwide.

 

We can provide a variety of spare parts for power plants, as follows:

#DF-Solenoid valve stem DSL101NR-DF

vacuum pump reducer M02225.013MVV1D1.5A

ACCUMULATOR BLADDER NXQ-40/31.5

cushion YCZ50-250 55*75*130*28 fluoro rubber

gear pump CB-B63

Needle globe valve WSJ-SN1V08FOD

EH oil seal O-ring HY-MF-257-V

pressure hose SMS-15/20-1524mm-C

solenoid directional valve D1VW004CNJW91

O-ring Y7-7

pressure hose SMS-10/12-305mm-C

Electric gate valve Z961Y-600LB

SEAT TP4Y611-4

O-ring GB3452.1 128*5.3-HN7445

mechanical Shutoff valve 11F02-02-01Y

EH Oil seal kit NXQ-B-10/10L

Bellows globe valve WJ25-F1.6P

Internal Poppet Valve of Soot Blowerr O0000373

Stainless steel ball valve 336BW012F01A

pressure relief valve YSF8-25/50

pressure relief valve YSF12-70/130-TA

EH Oil accumulator bladder SB330-24A1/114A9-330A

Solenoid Valve 8210G088

Heater drain pump SDSN65-100X2A

EH oil system main door solenoid valve 4WE6C50/AW22050NZ4V

Reheater outlet plug valve SD61H-P58.460V

Power plant shut-off valves WJ65F3.2P

Tensioning ring HPT300-340-03-08

Stop valve J61Y-P5650I

key DG600-240-03-23

Van thủy lực / Hydraulic valve F3DG5S2-062A-220DC-50-DFZKV/B8

O-ring HY-SO-0187-V

Rotary valve HH6220DC12 3/4

mechanical seal 24SAP-28

solenoid directional valve AWE10E10AW220V25L

Servo valve 0508.1193T0102.AW020

Check valve H61Y-1500LB SA-182 F22

Solenoid valve stem DSL101NR NTPL power

 

servo valve 078N209E

solenoid valve PVLC121608

Check valve H61Y-64I

module HTCV25-3

RUBBER BLADDER NXQ A25/31.5-L-EH

seals (cylinder diaphragm, packing, valve sealing gasket) 0125ZMAW16BQ13UNOERHDN125

EH oil pump PVH74QIC-RSM-1S-10-C25-31

AST solenoid valve GS061600V+CCP230M

Medium pressure regulating steam valve oil engine seal YJM-133C

The electromagnetic valve 4WE6YL6X/EG220NZ4/V

accumulator NXQ-AB-40/31.5-F-Y

Pressure Relief Valve YSF16-70*130KKJ

sealing ring HB4-56J8-181

valve DR2P20S

Fluorine rubber ring DH.00.006

High Voltage Dust ignition Proof Three Phase Induction Motor YFB4001-4WF2 Q/NF014-2016

Electric stop valve J961Y-P55160I SA-182 F22

Solenoid valve 4WE10D50/EG220N9K4/V

Internal cooling water stop check valve K25JC-1.6P

Bushing CPN89292478

External thread connector KQ2H11-34S 

Regulating valve diaphragm 1002GCN36XXCXAQOST

plug for MOOG valve 49054F014S002S

pressure relief valve YSF12-55/130-KJTA

accumulator NXQ-A-40/31.5-F-Y

Solenoid directional valve 4WE6U61B/CW220RN9Z5L

Stop valve J61Y-160I

cooling water pump DFB-100-80-230

AST/OPC solenoid valve coil 300AA00309A

The electromagnetic valve 4WE6D62/EW230N9KX/B08

solenoid valve DG4V-3S-6C-MU-H5-60

regulating valve 130TJ3

Needle valve L61Y-320P 304

Electric stop valve J961Y-P55.5150V 12Cr1MoV

gear pump 02ZCG17N438D

Emergency stop solenoid valve 4WE-6-D62/EG24N9K4

Solenoid valve stem DSL101NR NTPL power

 

DFYLMY-2026-9-11-A