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Differential Pressure Regulating Valve
Thank you very much for choosing the Yoshitake's product. To ensure the correct and safe use of the
product, please read this manual before use. This manual shall be kept with care for future references.
The symbols used in this manual have the following meanings.
Warning
Caution
1. Usage of the product ·················································· 1
2. Features ·································································· 1
3. Specifications ···························································· 1
4. Dimensions and Weight ·············································· 2
5. Operation ································································· 3
6. Nominal Size Selection ··············································· 4
6.1 Nominal sizes selection chart ·································· 4
6.2 Calculation formula for Cv value ······························ 4
7. Installation ································································ 5
8. Operating Procedure ·················································· 7
9. Maintenance ····························································· 7
10. Troubleshooting ······················································· 9
11. Exploded Drawing ··················································· 10
MODEL GD-21
PRODUCT MANUAL
This symbol indicates a potentially hazardous situation that, if not avoided,
could result in death or serious injury.
This symbol indicates a hazardous situation that, if not avoided, may result in
minor or moderate injury or may result in only property damage.
7.1 Precautions for installation ····································· 5
7.2 Piping example ···················································· 6
8.1 Precautions for operation ······································· 7
8.2 Precautions for air vent ········································· 7
8.3 How to use air vent ··············································· 7
9.1 Precautions for disassembly and maintenance ··········· 7
9.2 Disassembly ······················································· 8
9.3 Reassembly ························································ 8
9.4 Precautions for reassembly ···································· 9
Table of Contents
EPDT-255b
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Summary of Contents for Yoshitake GD-21
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Page 1: Table Of Contents
Differential Pressure Regulating Valve PRODUCT MANUAL Thank you very much for choosing the Yoshitake’s product. To ensure the correct and safe use of the product, please read this manual before use. This manual shall be kept with care for future references. -
Page 2: Usage Of The Product
1. Usage of the Product The GD-21 is used for pump in a closed circuit of air-conditioning or heating equipment in mid-rise and high-rise buildings. While an open circuit requires a primary pressure reducing valve as relief valve for pump, a closed circuit requires a differential pressure regulating valve since it is necessary to operate the pump at a constant flow rate no matter how back pressure fluctuates. -
Page 3: Dimensions And Weight
EPDT-255b 4. Dimensions and Weight (mm) Nominal size Weight (kg) 10.1 17.4 17.4 19.3 40.1 43.8 100A 70.1 125A 144.1 150A 173.1... -
Page 4: Operation
EPDT-255b 5. Operation Size 15A-50A Parts Name Body Spring Chamber Retainer Retainer Guide Spindle Valve Seat Valve Outlet pressure Diaphragm sensing port Rc 3/8 Spring Plate 10 Spring Plate 11 Adjusting Spring 12 Adjusting Screw 13 Lock Nut 14 Cap 15 U Nut 16 Conductor Pipe 17 Air Vent... -
Page 5: Nominal Size Selection
EPDT-255b 6. Nominal Size Selection 6.1 Nominal size selection chart (For water) Nominal size ∆P: Differential pressure (MPa) [Example] When selecting the nominal size of a differential pressure regulating valve with differential pressure (∆P) of 0.2 MPa and flow rate (V) of 5.5 m /h, find the intersection point (a) of differential pressure (∆P) and the flow rate (V). -
Page 6: Installation
EPDT-255b 7. Installation 7.1 Precautions for installation Caution 1. As the product is heavy, support it securely by lifting device while installation. * Failure to follow this notice may result in bodily injury due to a drop accident. 2. Do not disassemble the product unless it is necessary. * Disassembly may prevent the product from functioning properly. -
Page 7: Piping Example
EPDT-255b 7.2 Piping example Two-way valve Air-conditioning equipment Two-way valve Air-conditioning equipment Return Supply header header GD-21 SU-20 Strainer Freezer or Pump heat source Fig. 2 Approx. 1000 mm Outlet pressure sensing port Rc 3/8 Needle SU-20 valve* Strainer * Install a needle valve to the outlet side of the... -
Page 8: Operating Procedure
EPDT-255b 8. Operating procedure 8.1 Precautions for operation Do not touch the product with bare hands when the fluid has a high-temperature. Warning * Failure to this notice may scald your skin. Caution 1. Before leading fluid into the product, close the stop valves before and after the product and remove all foreign substances or scales via the bypass line. -
Page 9: Disassembly
EPDT-255b 9.2 Disassembly (1) Release the internal pressure from the piping completely, and make sure that the pressure gauge shows that the pressure is zero. (2) Remove the cap [14] and slightly loosen the lock nut [13], and then turn the adjusting screw [12] counterclockwise so that the adjusting spring [11] can be in no load condition. -
Page 10: Precautions For Reassembly
EPDT-255b 9.4 Precautions for reassembly Caution 1. Make sure that there are no flaws on the diaphragm [8], the valve seat [6] and the valve [7]. * Flaws on them may prevent the product from functioning properly. 2. Apply silicon grease to the O-ring [20] after confirming that there are no flaws on it. * Without silicon grease, the O-ring may be torn. -
Page 11: Exploded Drawing
EPDT-255b 11. Exploded Drawing Gasket Adjusting screw Retainer Retainer O ring O ring O ring O ring Bolt Lock nut Bolt Retainer guide Bolt Retainer guide Spring chamber O ring O ring O ring Air vent Name plate 15A – 50A 65A –... -
Page 12: Warranty Information
Fire, flood, earthquake, thunder and other natural disasters. Consumable parts such as O-ring, gasket, diaphragm and etc. Yoshitake is not liable for any damage or loss caused by malfunction or defect of the product. INTERNATIONAL DEPT. 955-5, Miyamae, Irukadeshinden, Komaki, Aichi, 485-0084, Japan...