Instruction Sheet Replacing a Gun RTD WARNING: Allow only qualified personnel to perform the following tasks. Observe and follow the safety instructions in this document and all other related documentation. 1. Introduction Resistance temperature detectors (RTDs) are used in Nordson RTD systems to control the temperature of applicators, hoses, and guns to within 0.5 C (1 F ) of the desired operating temperature. This instruction sheet provides procedures for replacing the RTD in Nordson H-20 and H-200 series automatic guns, including water-wash H-200 guns. Using this Instruction Sheet This instruction sheet contains the following procedures: Accessing the RTD Replacing the RTD Using Terminal Blocks Replacing the RTD Using Wire Nuts Be sure to use the correct procedure for the type of RTD replacement you are performing. The RTD replacement kit contains both terminal blocks and wire nuts. Terminal blocks must be used on guns that are required to meet Conformité Européenne (CE) standards. Use the parts lists at the end of this instruction sheet to order additional RTD replacement kits or individual parts.
2 Replacing a Gun RTD 2. Accessing the RTD Use this procedure before performing either of the RTD replacement procedures. The RTD is located in a bore in the manifold body. WARNING: Risk of burns. Relieve pressure. Air trapped in the hoses and guns can spit out molten adhesive that can cause severe burns. Failure to relieve hydraulic pressure can result in serious burns. 1. Relieve hydraulic pressure by following the instructions in the applicator manual. WARNING: Risk of shock. Even when switched off, Nordson applicators, hoses, and guns contain electrical potentials that can cause death. Disconnect and lock out line voltage to the applicator. 2. Move the applicator circuit breaker to the OFF position, then disconnect and lock out input electrical power to the applicator. 4201069 Fig. 1 Typical Facility and Applicator Circuit Breakers
Replacing a Gun RTD 3 2. Accessing the RTD (contd.) WARNING: Hot! Risk of burns. Wear heat-protective gloves. 3. Disconnect the air supply line and triggering device from the gun s solenoid valve. 4. Disconnect the pipe nipple from the gun. 5. Unplug the gun s cordset from the hose plug receptacle. 6. Use two wrenches to disconnect the hose from the gun. Place one wrench on the gun fitting and one on the hose fitting. 1 2 3 4201071 Fig. 2 Disconnecting the Gun from the Solenoid Valve and Hose (Typical) 1. Disconnecting the pipe nipple 2. Unplugging the gun 3. Disconnecting the gun from the hose 1 2 3 7. Loosen the mounting clamp pan-head screws until the gun is freed from the mounting clamp, or take the appropriate steps to disconnect your gun from its mount. Be sure to retain the insulator. 8. Remove the manifold body cover screws, then move the cover away from the manifold body. 4201047 Fig. 3 Disconnecting the Gun from the Unit and Removing the Manifold Body Cover (Typical) 1. Mounting bracket 2. Insulator 3. Manifold body cover
4 Replacing a Gun RTD 3. Replacing the RTD Using Terminal Blocks Use this procedure to replace an RTD using terminal blocks and eyelets. If you are using wire nuts, go to Replacing the RTD Using Wire Nuts. 1. Remove the defective RTD from the bore in the manifold body. 1 NOTE: On most guns, a 4.7-mm ( 3 / 16 -in.) punch can be used to loosen an RTD if it is stuck inside the bore. Although an RTD resembles a heater, which is also located in a bore in the manifold body, the RTD is smaller in diameter and is connected directly to the cordset through two wires. 2. Cut the two RTD wires approximately 13 mm ( 1 / 2 in.) from the defective RTD. Discard the defective RTD. 2 3. Cut the new RTD wires to a length appropriate for installation. Fig. 4 Typical Gun RTD and Heater 4201082 1. RTD 2. Heater
Replacing a Gun RTD 5 3. Replacing the RTD Using Terminal Blocks (contd.) NOTE: See Figure 5 for steps 4 through 8. 4. Strip about 9.5 mm ( 3 / 8 in.) of insulation from each RTD wire (both the new RTD wires and the cordset RTD wires). 5. Fold the exposed portion of each stripped wire in half to ensure a secure fit inside the eyelet. 6. Insert each wire into an eyelet (one wire per eyelet). 7. Insert the eyelets into terminal blocks as shown in Figure 5. NOTE: It does not matter which new RTD wire is connected to which cordset RTD wire because the RTD is not polarity-sensitive. 8. Secure and crimp the eyelets by tightening the terminal block screws. Torque to approximately 0.49 N m (70 in-oz). The eyelets are specially designed to be crimped by tightening the screw. 1 2 3 4 5 7 6 4201086 Fig. 5 RTD Wire Connections Using Terminal Blocks 1. New RTD 5. Cordset (RTD wires only shown) 2. New RTD wire 6. Exposed wire folded in half 3. Terminal block with eyelets inserted 7. Eyelet 4. Cordset RTD wire
6 Replacing a Gun RTD 3. Replacing the RTD Using Terminal Blocks (contd.) 9. Slide the RTD into the bore in the manifold body (see Figure 4). CAUTION: When reinstalling the manifold body cover, do not pinch the wires between the cover and the manifold body. Pinched wires can cause the gun to fail. 10. Replace the manifold body cover and secure it with the cover screws. 11. Reconnect the gun to the mounting clamp using the mounting clamp pan-head screws, or take the appropriate steps to reconnect the gun to your unit. Be sure to place the insulator between the mounting clamp and gun. 12. Reconnect the pipe nipple to the gun, then reconnect the solenoid valve to the air supply line and triggering device. 13. Use two wrenches to reconnect the hose to the gun. Place one wrench on the gun fitting and the other on the hose fitting. 14. Plug the gun s cordset into the hose plug receptacle. 15. Restore the system to normal operation by following the instructions in the applicator manual. 4. Replacing the RTD Using Wire Nuts Use this procedure to replace an RTD using wire nuts. Remember that the use of wire nuts without secondary strain relief voids CE approval. 1. Remove the RTD from the bore in the manifold body. 1 NOTE: On most guns, a 4.7-mm ( 3 / 16 -in.) punch can be used to loosen an RTD if it is stuck inside the bore. Although an RTD resembles a heater, which is also located in a bore in the manifold body, the RTD is smaller in diameter and is connected directly to the cordset by two wires. 2 4201082 Fig. 6 Typical Gun RTD and Heater 1. RTD 2. Heater
Replacing a Gun RTD 7 4. Replacing the RTD Using Wire Nuts (contd.) NOTE: See Figure 7 for steps 2 through 4. 2. Cut the two RTD wires approximately 13 mm ( 1 / 2 in.) from the defective RTD. Discard the defective RTD. 3. Strip about 7 mm ( 1 / 4 in.) of insulation from the cut RTD wires coming from the cordset. 4. Follow these steps to connect the wires: a. Twist each wire s exposed portion into a smooth strand of wire (do not twist the separate wires together at this point). b. Position one new RTD wire and one cordset RTD wire together, then use a wire nut to twist the wires together and secure them. c. Repeat steps a and b for the other new RTD and cordset RTD wire. NOTE: It does not matter which new RTD wire is connected to which cordset RTD wire because the RTD is not polarity-sensitive. 1 2 3 4 5 6 4201087 Fig. 7 RTD Wire Connections Using Wire Nuts 1. New RTD 4. Cordset RTD wire 2. New RTD wire 5. Cordset (RTD wires only shown) 3. Wire nut 6. Exposed wires
8 Replacing a Gun RTD 4. Replacing the RTD Using Wire Nuts (contd.) 5. Slide the RTD into the bore in the manifold body (see Figure 6). CAUTION: When reinstalling the manifold body cover, do not pinch the wires between the cover and the manifold body. Pinched wires can cause the gun to fail. 6. Replace the manifold body cover and secure it with the cover screws. 7. Reconnect the gun to the mounting clamp using the mounting clamp pan-head screws, or take the appropriate steps to reconnect the gun to your unit. Be sure to place the insulator between the mounting clamp and gun. 8. Reconnect the pipe nipple to the gun, then reconnect the solenoid valve to the air supply line and triggering device. 9. Use two wrenches to reconnect the hose to the gun. Place one wrench on the gun fitting and the other on the hose fitting. 10. Plug the gun s cordset into the hose plug receptacle. 11. Restore the system to normal operation by following the instructions in the applicator manual.
Replacing a Gun RTD 9 5. Parts To order additional RTD replacement kits or parts, call the Nordson Customer Service Center or your local Nordson representative. Use the following parts lists to describe and locate parts correctly. Table 1 RTD Replacement Kit for Standard Guns Part Description Quantity 274 783 Service Kit, RTD Replacement 274 731 Sensor, Temperature, Gun 1 933 056 Connector, Wire, Porcelain 2 226 769 Kit, Eyelets (Package of 25) 1 939 994 Connector Assembly, Plastic, 1-Station 2 Table 2 RTD Replacement Kit for Water-Wash Guns Part Description Quantity 226 770 Service Kit, RTD Replacement, T Series (Water-Wash) 939 739 Sensor, Temperature, Gun, 48.0-in. Leads 1 933 056 Connector, Wire, Porcelain 2 226 769 Kit, Eyelets (Package of 25) 1 939 994 Connector Assembly, Plastic, 1-Station 2
10 Replacing a Gun RTD Original copyright date 1986. Nordson and the Nordson logo are registered trademarks of Nordson Corporation.