PartsTable
Technical Data Sheet

566-1/2 4IN — THERMAL RELEASE,CIRCUIT BREAKER

✓ Government record, cited
— · HOSE FITTING
PRODUCT OVERVIEW

566-1/2 4IN: THERMAL RELEASE,CIRCUIT BREAKER.

THERMAL RELEASE,CIRCUIT BREAKER. Key specifications include material: STEEL, thickness: 0.938 INCHES NOMINAL IN, flange_diameter: 9.000 INCHES NOMINAL IN, furnished_items: GASKET, style_designator: ROUND, ONE BOLT HOLE CIRCLE, bolt_hole_diameter: 0.750 INCHES NOMINAL IN. This part is cataloged in the U.S.

Government catalog under NSN 4730-00-555-1570, indicating validated use in U.S. government and defense logistics supply chains. Available through authorized enterprise resellers and TPM (Third Party Maintenance) channels.

Verify compatibility with your specific system configuration before ordering.

WHERE IT FITS
566-1/2 4IN
NSN: 4730-00-555-1570
FSC: 4730 — Hose, Pipe, Tube, Lubrication, and Railing Fittings
CAGE: 14959 — CRANE CO DIV VALVE DIV (USA)
SPECIFICATIONS
materialSTEEL
thickness0.938 INCHES NOMINAL IN
flange_diameter9.000 INCHES NOMINAL IN
furnished_itemsGASKET
style_designatorROUND, ONE BOLT HOLE CIRCLE
bolt_hole_diameter0.750 INCHES NOMINAL IN
bolt_hole_quantity8
raised_face_height0.062 INCHES NOMINAL IN
bolt_circle_diameter7.500 INCHES NOMINAL IN
flange_section_styleRAISED FACE (BLIND)
operating_pressure_and_type150.0 POUNDS PER SQUARE INCH (PSI) GAS MAXIMUM REQUIRED AND 150.0 POUNDS PER SQUARE INCH (PSI) OIL MAXIMUM REQUIRED AND 150.0 POUNDS PER SQUARE INCH (PSI) WATER MAXIMUM REQUIRED LBS
face_seating_surface_conditionMACHINED
NSN4730-00-555-1570
COMPONENT DIAGRAM
HOSE FITTING — THREAD TYPE IS CRITICAL END A: — STRAIGHT END B: — SPECIFICATIONS Thread: — Material: — Pressure: — PN: 566-1/2 4IN · OEM ⚠ VERIFY BEFORE ORDERING NPT ≠ BSPT — tapered threads look identical but are NOT interchangeable. Wrong thread = leak. JIC (37°) ≠ AN (37°) ≠ SAE 45° — flare angles must match exactly. Measure thread pitch with gauge — visual identification is unreliable ✓ BROKER TIP Always use thread sealant (PTFE tape or pipe compound) on tapered threads (NPT/BSPT). JIC/AN flare fittings seal metal-to-metal — never use tape on flare connections PARTSTABLE TECHNICAL DRAWING — NOT TO SCALE
KEY FEATURES
•
FLANGE DIAMETER: 9.000 INCHES NOMINAL IN
•
FACE SEATING SURFACE CONDITION: MACHINED
•
NOMINAL PIPE SIZE FOR WHICH DESIGNED: 4.000 INCHES IN
•
MAXIMUM OPERATING TEMP AND MEDIA FOR WHICH DESIGNED: 500.0 FAHRENHEIT GAS AND 500.0 FAHRENHEIT OIL AND 500.0 FAHRENHEIT WATER DEGF
•
OPERATING PRESSURE AND TYPE: 150.0 POUNDS PER SQUARE INCH (PSI) GAS MAXIMUM REQUIRED AND 150.0 POUNDS PER SQUARE INCH (PSI) OIL MAXIMUM REQUIRED AND 150.0 POUNDS PER SQUARE INCH (PSI) WATER MAXIMUM REQUIRED LBS
•
FLANGE SECTION STYLE: RAISED FACE (BLIND)
•
STYLE DESIGNATOR: ROUND, ONE BOLT HOLE CIRCLE
•
BOLT HOLE DIAMETER: 0.750 INCHES NOMINAL IN
TECHNICAL CHARACTERISTICS
FLANGE DIAMETER9.000 INCHES NOMINAL IN
FACE SEATING SURFACE CONDITIONMACHINED
NOMINAL PIPE SIZE FOR WHICH DESIGNED4.000 INCHES IN
MAXIMUM OPERATING TEMP AND MEDIA FOR WHICH DESIGNED500.0 FAHRENHEIT GAS AND 500.0 FAHRENHEIT OIL AND 500.0 FAHRENHEIT WATER DEGF
OPERATING PRESSURE AND TYPE150.0 POUNDS PER SQUARE INCH (PSI) GAS MAXIMUM REQUIRED AND 150.0 POUNDS PER SQUARE INCH (PSI) OIL MAXIMUM REQUIRED AND 150.0 POUNDS PER SQUARE INCH (PSI) WATER MAXIMUM REQUIRED LBS
FLANGE SECTION STYLERAISED FACE (BLIND)
STYLE DESIGNATORROUND, ONE BOLT HOLE CIRCLE
BOLT HOLE DIAMETER0.750 INCHES NOMINAL IN
BOLT HOLE QUANTITY8
BOLT CIRCLE DIAMETER7.500 INCHES NOMINAL IN
SUBSTITUTES & CROSS-REFERENCES 3
556-1-2Reference document
Same NSN cross-reference
Reference document — Secondary reference
M18180/6-010A01Reference document
Same NSN cross-reference
Reference document — Secondary reference
B16.5Reference document
Same NSN cross-reference
Reference document — Design control — primary reference
LIFECYCLE
NSN statusCancelled· U.S. Government catalog
Acquisition advice: Normally procured from the manufacturer (OEM)No demilitarization required
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FREQUENTLY ASKED QUESTIONS
What is 566-1/2 4IN?
566-1/2 4IN is a THERMAL RELEASE,CIRCUIT BREAKER.
What parts can replace 566-1/2 4IN?
There are 3 known substitutes for 566-1/2 4IN: 556-1-2, M18180/6-010A01, B16.5. Substitute compatibility should be verified for your specific system.
What is the NSN for 566-1/2 4IN?
566-1/2 4IN is cataloged in the U.S. Government catalog under NSN 4730-00-555-1570. This indicates validated use in U.S. government and defense supply chains.
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✓ PartsTable — the parts reference. Every fact cited to its source.
PartsTable Design LLC · partstable.com
U.S. Government catalog: edition PUBLOGDVD v12.0.0 (OCT 2026), edition date 2026-10-01, retrieved 2026-10-18.
PartsTable commercial catalog: edition Unified commercial catalog snapshot through 2026-09-28, edition date not on file, retrieved 2026-09-28.