Quick Coupling Division
8145 Lewis Road • Minneapolis, MN 55427
www.parker.com/quickcouplings
B-55
Hydraulic Quick Couplings
B
Hydraulics
High Flow Couplings
HO Series
Applications
HO Series couplings are used in a wide variety of
applications. HO couplings are used in refineries, petro-
chemical plants and paper and pulp mills for connecting
hose lines for high pressure hydro-blasting of boilers and
pipe lines. They are also used in oil fields on hose lines
for internal and external pressure testing of tubing.
Note:
Protective dust plugs and caps play a crucial role
in the life of a quick coupling and no purchase of a
hydraulic quick coupling is complete without the selection
of an appropriate dust plug and cap. See pages noted in
Table of Contents for hydraulic couplings dust plugs and
caps for the full line of hydraulic couplings.
Features
• For high pressure applications: working pressures to 15,000
PSI (1,050 Bar) for the 1/4” and 3/8” sizes; to 10,000 PSI
(700 Bar) for the 1/2” size.
• No internal valving to restrict flow.
• Made of steel with electroless nickel plating for corrosion
resistance.
• Standard sleeve-lock feature which helps prevent accidental
disconnect.
• Standard Nitrile Body O-Ring. Backed up by PTFEwasher
to prevent seal extrusion.
Couplers
Nipples
G
F
E
D
C
B
A
Specifications
Body Size (in.)
1/4
3/8
1/2
Rated Pressure (PSI)
15,000
15,000
10,000
Rated Flow (GPM)
3
6
12
Temperature Range (std seals)
-40° to +250°F
Body
Thread Dimensions (in.)
Size
Part
Size
Overall
Hex Largest Wt. (LB.)
(in.)
No.
NPSF
Length
Size Diameter P/Piece
A
B
C
1/4 HO-251-4FP 1/4-18
1.67
0.94 1.06 0.24
3/8 HO-371-6FP 3/8-18
1.67
0.94 1.06 0.22
1/2 HO-501-8FP 1/2-14
2.03
1.25 1.62 0.52
Body
Thread
Dimensions (in.)
Size
Part
Size Overall
Exposed Hex Largest Wt. (LB.)
(in.)
No.
NPSF Length Length Size Diameter P/Piece
D
E
F
G
1/4 HO-252-4FP 1/4-18 1.40
0.66
0.81 0.94 0.10
3/8 HO-372-6FP 3/8-18 1.44
0.70
0.94 1.08 0.12
1/2 HO-502-8FP 1/2-14 2.03
0.86
1.12 1.30 0.26
NPSF – National Pipe Straight Fuel