Yoshitake GP-1200 and GP-1210 are air-loaded pilot-operated pressure reducing valves specifically designed for steam applications. Functioning as pneumatic, remote-type valves, they are exceptionally well-suited for systems requiring centralized control or frequent adjustments to the pressure setting. These valves provide stable and reliable pressure control for a wide range of flow rates in building utilities, air-conditioning networks, and industrial factory systems.

Features

• Remote Control Capability: Pneumatic air-loaded design enables convenient remote pressure adjustment.
• High Sealability: Main valve design ensures significant reduction in valve seat leakage (0.01% or less of rated flow).
• Robust Construction: Ductile cast iron body combined with stainless steel main valve and valve seat for superior durability.
• Versatile Applications: Handles small to large flow rates effectively.

Specifications

Specification	GP-1200	GP-1210
Application	Steam	Steam
Inlet Pressure	0.1 - 1.0 MPa	0.1 - 1.0 MPa
Reduced Pressure	0.05 - 0.9 MPa	0.05 - 0.9 MPa
Pressure Constraint	90% or less of inlet pressure	90% or less of inlet pressure
Minimum Differential Pressure	0.05 MPa	0.05 MPa
Max. Pressure Reduction Ratio	20:1	20:1
Maximum Temperature	220°C	220°C
Valve Seat Leakage	0.01% or less of rated flow	0.01% or less of rated flow
Connection	Flanged (JIS 10K FF)	Screwed (JIS Rc)

Dimensions and Weights

GP-1200 (Flanged JIS 10K FF)

Nominal Size	L (mm)	H1 (mm)	H (mm)	Weight (kg)
15A	150	64	220	8.0
20A	155	64	220	8.5
25A	160	67	235	10.0
32A	190	82	258	14.0
40A	190	82	258	14.5
50A	220	93	282	20.0
65A	245	100	292	30.0
80A	290	122	339	35.0
100A	330	144	385	52.5

GP-1210 (Screwed JIS Rc)

Nominal Size	d	L (mm)	H1 (mm)	H (mm)	Weight (kg)
15A	Rc 1/2	150	64	220	7.0
20A	Rc 3/4	155	64	220	7.0
25A	Rc 1	160	67	235	8.5
32A	Rc 1-1/4	190	82	258	12.0
40A	Rc 1-1/2	190	82	258	12.5
50A	Rc 2	220	93	282	18.0

Operation Mechanism

1. When correctly mounted with no air loading pressure, the main valve and pilot valve are closed by spring force.
2. Introducing air pressure into the air chamber flexes the pilot diaphragm to open the pilot valve.
3. Inlet pressure flows via the pilot valve to the top of the piston. This pressure overrides the main valve spring and the pressure beneath the main valve, causing it to open and allowing steam to flow.
4. Reduced downstream pressure is routed to the diaphragm chamber via a sensing port, balancing against the air loading pressure to precisely control the pilot valve travel.
5. Adjustments to the pilot valve automatically modulate the flow to the piston, smoothly controlling main valve travel and maintaining a consistent reduced pressure.

Installation Precautions

• Strainer: Always install a strainer (80 mesh) at the valve inlet side to prevent foreign matter from compromising pressure control.
• Safety Valve: Install a safety valve at the outlet side to protect downstream equipment.
• Steam Trap: Fit a steam trap at the inlet side to prevent condensate and drainage issues.
• Maintenance Space: Ensure adequate clearance on the top and bottom of the valve for straightforward disassembly and inspection.
• Valve Position: Install the valve perpendicularly to horizontal lines.

Maintenance and Troubleshooting

Problem	Cause	Solution
Pressure does not reach the desired value	Operating air pressure is insufficient. Strainer is clogged. Foreign matter exists between piston and cylinder. Piston ring is damaged.	Raise the operating air pressure to the necessary set pressure. Disassemble and clean the strainer. Remove foreign matter or replace the piston ring.
Reduced pressure raises above the specified value	Foreign matter or scratches exist between main/pilot valve and seat. Bypass valve is leaking. Diaphragm is damaged.	Disassemble and remove foreign matter, or lap/replace sealing parts. Repair or replace the bypass valve. Replace the diaphragm.
Abnormal noise is heard	Nominal size is too large for the specifications. Pressure reducing ratio is too large. Drainage problem.	Re-evaluate valve sizing, install a trap for drainage, or check for proper reduction ratios.