Service Manual General Purpose Water Baths

Transcription

1 Water Bath Manual, Page 1 Service Manual General Purpose Water Baths Information is reserved for trained, qualified technical personnel. It includes schematics & wiring diagrams. Any repair or service to a unit is to be performed by a certified technician ONLY. Attempting repairs outlined in this guide may result in voiding your warranty UNPLUG THE UNIT BEFORE SERVICING WATER BATHS ON SAFETY SET TEMPERATURE SET C TEMPERATURE C OFF Water Bath Microprocessor Controlled Water Bath Table of Contents SECTION 1. TROUBLESHOOTING GUIDE SECTION 2. GENERAL INFORMATION SECTION 3. REPLACING MAIN CONTROL BOARD SECTION 4. SENSOR MOUNTING SECTION 5. INFORMATION TABLE SECTION 6. CALIBRATION SECTION 7. HI-POT TEST SECTION 8. MAIN BAORD CONTINUITY CHART SECTION 9. SPARE PARTS LIST SECTION 9. SCHEMATICS & WIRING DIAGRAMS 1

2 Water Bath Manual, Page 2 SECTION 1. TROUBLESHOOTING GUIDE Note: If the unit seems to function normally but fails to control or hold temperature steady, first perform instructions as in "Conditions and Steps before Troubleshooting the Unit" Conditions and Steps before Troubleshooting the Unit 1. A Hi-Pot test should be performed first before any servicing, see "HI-POT TEST" in sect Use the same fluid and the same setpoint temperature as the application. 3. Check that the fluid or fluid mixture is: a. Watery, not thick like maple syrup. Viscosity <25 centistokes. b. Not boiling on the surface and not within 5 C of the boiling point of the liquid. 4. Fluids within 40 C of their boiling point may experience vapor loss. Use the cover or add insulation (hollow floating plastic or Teflon balls) to the fluid in the tank. 5. For Microprocessor Controlled Models - To return to the factory default setting: Press and release the Power On button, then switch off the power switch. Press and hold the Set/Menu button while switching on the power switch. The controller will display "DEF" and go to the standby mode. Your set temperature and other settings will have to be reset. WATER BATH TROUBLESHOOTING CHART PROBLEM #1 No power light #2 Breaker trips #3 Unit does not heat or only intermittent heat #4 Unit won't reach setpoint Corrective action Breaker must be on. If not, check light in switch. Heater may be shorted to ground. Perform "Hi-Pot test" in sect. 7. Check heater resistance. See "Information table", sect. 5. Check supply +8.6VDC ± 0.2 volts. If low, check R2/R3 for proper resistance. If still low or high, replace U1. If still low, check C1 for leaky or shorted condition. Also, check R4/R5 for proper resistance. Check heater resistance in "Information table" sect. 5. (a) Use the cover. Maximum of 60 C without cover. Check that the safety knob is higher than your setpoint. (c) If the safety is on too early, see "Sensor mounting" sect. 4. (d) Check PR1. See "Sensor mounting" instructions. (e) Check for DC on heater. If more than 30 DC volts, replace Triac. #5 Unit continuously heats (a) Heater may be shorted to ground. Perform "Hi-Pot test" in sect. 7. Triac may be shorted. (c) Triac may be improperly heat-sinked. Check that Triac and aluminum disc surfaces are thermally greased. (d) Remove U1. If heat stays on, Triac is shorted. (e) If Triac okay, replace U1 or check P1 connections. 2

3 Water Bath Manual, Page 3 #6 Unstable temperature control #7 No readout (a) Check PR1. See "Sensor mounting" sect. 4. For instructions. Check that user is not near freezing or boiling point of liquid. (c) User may be using the bath at a high temperature without using the gabled cover supplied with the unit. Check for 12VAC at transformer, if okay replace readout board. #8 Readout not within ± 1 C #9 Setpoint knob not accurate. After letting the unit settle for more than one hour. Use the small hole in the front panel to trim the reading. If it will not calibrate, check the temperature sensor as in the section "Sensor mounting" sect. 4. If still not okay replace readout board. Check that the setpoint knob is within ± 5 C of the bath. If not, check that the knob is centered on scale. If centered, check that probe resistance is within 35 ohms of "Information table" sect. 5. TEMPERATURE : 20 C 25 C 30 C 40 C 45 C 50 C PR1 SENSOR OHMS : MICROPROCESSOR CONTROLLED WATER BATHS TROUBLESHOOTING CHART #1 Display does not light up (a) Check that Breaker CB1 and rear power switch S1 are on. Check proper insertion of ribbon cable J1 and EPROM U3. (c) Check main board +5V at voltage regulator RG1. (d) First replace main board, then replace display board. #2 Breaker Trips #3 Flashes HI-L High Limit #4 Reads E-5F Sensor Failure Heater may be shorted to ground. Perform "Hi-Pot test" in sect.7. Check heater resistance in "Information table" sect. 5. (a) (a) (c) Raise HI-L above fluid temp. with SET/MENU HI-L menu. Check sensor resistance shown on service schematic. Check sensor voltage and resistance shown on schematic. Check main board -5V at voltage regulator RG2. If resistance and voltages okay, replace main board. #5 Reads E-tF Triac Failure #6 Heat light on but no heat #7 Heat at full power but won't reach setpoint (a) (a) (a) (c) Replace alternistor ALT1. Replace main board. Check heater resistance. Check wiring to H1, S2 and ALT1. Check for open R3, ALT1 and U1 or replace main board. Use the cover. Maximum of 60 C without cover. Check that OTP knob was set higher than setpoint. Check for DC on the heater. If more than 30 DC volts, replace alternistor ALT1. 3

4 Water Bath Manual, Page 4 #8 Heat light flashes, but control never stabilizes (a) (c) (d) Use the cover. Maximum of 60 C without cover. If fluid is at boiling point, raise fluid boiling point. Check that PR1 and S2 sensors are properly mounted. Replace main board. Use new sensor that comes with board. #9 Readout inaccurate (a) There is no calibration adjustment. Tolerance is ± 0.5C Check sensor resistance. (c) Check that PR1 sensor is properly mounted as in section "SENSOR MOUNTING" in sect. 4. SECTION 2. GENERAL INFORMATION 2.2 SAFETY Electrical: Equipment should be unplugged before any person enters the unit. The unit should always be operated from a properly grounded outlet. Insulated adjustment tools should be used during calibration. A Hi-Pot test should be performed first before any servicing, see "HI-POT TEST" in sect. 7 Chemical: The unit is not rated for use with any flammable, strongly corrosive, biological or radioactive liquids. Any chemicals used in the circulating fluid such as Ethylene Glycol may present a hazard to the user. Precautions should be taken according to the substances used. Solvents may cause damage to plastics used. See section "FLUIDS" for list of bath fluids that are not recommended. Temperature: Temperatures above 70 C may cause burns. Above 80 C high temperature or metal containers, fittings, and tubing are required. Above 100 C extreme caution should be exercised to avoid burns. Personnel not familiar with the equipment should be restricted from the area. Objects removed from baths may drip hot fluid onto skin or clothing. The bath should not be placed near the edge of a table. Circulating lines should not be placed in such a way that they may pull the unit sideways or tip over the unit. Sliding a bath across a table may cause waves that can splash hot liquid. High temperature fluids expand as heated. When filling with high temperature fluids, allow room for expansion of the fluid by filling at a lower level FLUIDS A variety of fluids can be used with the water baths depending upon the operators needs. The fluid must be compatible with stainless steel and have a viscosity of less than 50 centistokes at the temperatures being used. If possible use distilled water for temperatures from 10 to 90 C and a 50/50 mixture of laboratory grade ethylene glycol and water for temperatures below 10 C. For higher temperature applications, use fluids that will satisfy safety, health, and compatibility requirements. Do not use any of the following solutions: Concentrations of acid or base. Any solutions with halide, chlorine, fluorine, sulfur or iodine. Chlorides or bleach. Chromates or chromium salts. Any flammable liquids. Automotive antifreeze. 4

5 Water Bath Manual, Page 5 SECTION 3. REPLACING MAIN CONTROL BOARD When removing/replacing the main control board, always remove/replace the bath temperature probe included with the board. Temperature probes are factory-checked to be within tolerance only when used with that board. SECTION 4. SENSOR MOUNTING For Water Baths: All sensors or sensing bulbs should be secure and epoxy cemented to the reservoir to allow good thermal transfer. Fiberglass insulation must surround the area around the sensors when the case assembly is closed. For Microprocessor Controlled Water Baths: To ensure stable and accurate temperature control, both temperature sensor and OTP sensor bulb should be secured by aluminum tape to the reservoir at the high end of the round edge of the tank. When installing RTD temperature sensor, do not bend the sensor body or the internal wires will break. Fiberglass must always cover the aluminum tape to avoid being directly heated by heat rising from the heater and to help hold down the tape. SECTION 5. INFORMATION TABLE. MODEL VOLTAGE TOTAL WATTAGE BREAKER AMPERAGE QUANTITY OF HEATERS EACH HEATER RESISTANCE 2L/2LS 120V 120W 6A L/2LS 240V 120W 6A L 120V 250W 6A L 240V 250W 6A L 120V 500W 12A L 240V 500W 12A L/28L 120V 1000W 12A L/28L 240V 1000W 12A 1 58 SECTION 6. CALIBRATION: FOR MICROPROCESSOR CONTROLLED WATER BATHS ONLY These units are rated to be within ± 0.5 C of NIST actual temperature over the entire temperature range. There is no calibration procedure. To check calibration you need to have a Nist traceable thermometer of known accuracy of ± 0.05 C accuracy or better. Check at a least two points, one cold and one hot. If the user's temperature extremes are known, check at or near these points. The readout must be within ±0.5 C over this range to pass. SECTION 7. HI-POT TEST Use a HI-POT current leakage tester. Check both hot and neutral connections to ground. Set the tester for a limit of 2 milliamperes. Test for one second at 1250 VRMS or one minute at 1000 VRMS. If no tester is available, measure the resistance from both hot and neutral to ground. Resistance should be greater than 10 megohms. If drifting reading or negative, check for residual DC voltage. If a tenth of a volt or more exists, there is probably a water leak into a defective heater, float switch or some other part of the unit. 5

6 Water Bath Manual, Page 6 SECTION 8. MAIN BOARD CONTINUITY CHART: FOR MICROPROCESSOR CONTROLLED WATER BATHS ONLY If all power supply voltages are present and the unit does not run, check all of these board traces in the chart below for continuity. Repair any two points by soldering a small wire across any of the two points that do not make connection. U12 and U2 are the same IC chip. FROM TO FROM TO FROM TO FROM TO U7,1 TP4 U7,17 U5,11 U6,9 U3,26 U7,50 U12,10 U7,1 U12,1 U7,18 U6,16 U6,11 U12,2 U7,51 U12,19 U7,2 C5,ß U7,19 RN,4 U7,38 U12,23 U7,52 U12,18 U7,3 C6,â U7,19 U6,5 U7,39 U12,21 U7,53 U12,17 U7,4 U7,7 U7,20 U6,4 U7,40 U12,24 U7,54 U12,16 U7,4 U7,8 U7,21 U5,3 U7,41 U12,25 U7,55 U12,15 U7,6 U11,7 U7,22 U6,3 U7,43 U12,3 U7,56 U12,13 U7,8 RN1,1 U7,23 RN1,8 U7,44 U12,4 U7,57 U12,12 U7,9 RN1,9 U7,25 CN9,4 U7,45 U12,5 U7,58 U12,11 U7,9 U6,17 U7,26 CN9,3 U7,46 U12,6 U7,62 U12,27 U7,11 U5,1 U6,6 U7,31 U7,47 U12,7 U7,63 U12,22 U7,14 U5,4 U6,7 U3,1 U7,48 U12,8 U7,16 U5,2 U6,8 U3,27 U7,49 U12,9 SECTION 9. SPARE PARTS LIST FOR BOTH WATER BATHS & MICROPORCESSOR CONTROLLED WATER BATHS FOR WATER BATHS REF# DESCRIPTION PART# CB1 CIRCUIT BREAKER 6 AMPERE FOR MODELS 2L-5L CB1 CIRCUIT BREAKER 12 AMPERE 10L-28L DSP1 TEMPERATURE DISPLAY *SENS H1 HEATER,CERAMIC,4",120W,120V FOR MODELS 2L-5L H1 HEATER,CERAMIC,4",120W,240V FOR MODELS 2L-5L H1 HEATER,AIRCOIL,500W,120V FOR MODEL 10L H1 HEATER,AIRCOIL,500W,240V FOR MODEL 10L H1 HEATER,AIRCOIL,1KW,120V FOR MODELS 20L-28L H1 HEATER,AIRCOIL,1KW,240VFOR MODELS 20L-28L J1 LINECORD,120V,WITH PLUG FOR USA/CANADA J1 LINECORD,240V,WITH PLUG FOR EUROPE J1 LINECORD,240V,WITH PLUG FOR AUSTRALIA

7 Water Bath Manual, Page 7 J1 LINECORD,240V,WITH PLUG FOR GREAT BRITAIN (UK) LMP1,LMP2 LAMP,NEON,RED,.25" DIA,120V LMP1,LMP2 LAMP,NEON,RED,.25" DIA,240V PCB1 PC BOARD,120V,TESTED FOR MODELS 2L-5L PCB1 PC BOARD,240V,TESTED FOR MODELS 2L-5L PCB1 PC BOARD,120V,TESTED FOR MODELS 10L-28L PCB1 PC BOARD,240V,TESTED FOR MODELS 10L-28L PR1 PROBE,RTD,1855 0C,TEMP SENSOR S2 SAFETY THERMOSTAT *SENS S1 POWER SWITCH,120V S1 POWER SWITCH,240V T1 TRANSFORMER,120V T1 TRANSFORMER,240V FOR MICROPROCESSOR CONTROLLER WATER BATHS REF# DESCRIPTION PART# ALT1 ALTERNISTOR,ISOLATED TAB,TECCOR,Q4025L9,25A,400V H1 HEATER PLATE,GPWB,500W,10L,120V H1 HEATER PLATE,GPWB,500W,10L,240V H1 HEATER PLATE,GPWB,1KW,20L,120V H1 HEATER PLATE,GPWB,1KW,20L,240V H1 HEATER,CERAMIC,120W,3-3/16" DIAMETER,120V H1 HEATER,CERAMIC,120W,3-3/16" DIAMETER,240V PCB1 GPWB MAIN PC BOARD ASM.,WITH RTD SENSOR,TESTED,120V PCB1 GPWB MAIN PC BOARD ASM.,WITH RTD SENSOR,TESTED,240V PCB2 GPWB LED DISPLAY PC BOARD ASSEMBLY,TESTED PR1 100 OHM 4-WIRE RTD TEMPERATURE SENSOR (TC.00385) S3 OTP SAFETY HYDRAULIC THERMOSTAT S3 KNOB KNOB FOR ABOVE THERMOSTAT S1 FRONT PANEL ROTARY ENCODER WITH 1/4" SHAFT S1 KNOB KNOB FOR ABOVE FRONT PANEL ROTARY ENCODER BLUE COLOR CAP NUMBER, (ORDER 2 PARTS FOR THIS KNOB)

8 Water Bath Manual, Page 8 CB1 CIRCUIT BREAKER,THERMAL,1-POLE,12A,10L/20L/28L,120V CB1 CIRCUIT BREAKER,THERMAL,1-POLE,6A,2L/2LS/5L,120V CB1 CIRCUIT BREAKER, MAGNETIC,2-POLE,6A,ALL 240V UNITS S2 REAR POWER SWITCH,(120V ONLY) J1 RIBBON CABLE WITH CONNECTORS,10 PIN,2L/5L/10L J1 RIBBON CABLE,WITH CONNECTORS,10 PIN,20L/28L FACEPLATE,FRONT PANEL,SELF ADHESIVE,SET/MENU,ON,OFF REPLACEMENT 304 STAINLESS STEEL TANK,2L REPLACEMENT 304 STAINLESS STEEL TANK,2LS REPLACEMENT 304 STAINLESS STEEL TANK,5L REPLACEMENT 304 STAINLESS STEEL TANK, REPLACEMENT 304 STAINLESS STEEL TANK,20L REPLACEMENT 304 STAINLESS STEEL TANK,28L OPTIONS AND ACCESSORIES PART# COVER ASSEMBLY,2L COVER ASSEMBLY,2LS,5L COVER ASSEMBLY,10L, COVER ASSEMBLY,20L,28L SAMPLE TRAY,2L SAMPLE TRAY,2LS,5L SAMPLE TRAY,10L SAMPLE TRAY,20L,28L SYPHON PUMP THERMOMETER CLIP

9 Water Bath Manual, Page 9 SECTION 10. SCHEMATICS & WIRING DIAGRAM Schematic, Main Board, Microprocessor Controlled Water Bath 9

10 Water Bath Manual, Page 10 Schematic, LED Display, Microprocessor Controlled Water Bath 10

11 Water Bath Manual, Page 11 Schematic and Wiring Diagram, Microprocessor Controlled Water Bath 11

12 Water Bath Manual, Page 12 Schematic and Wiring Diagram, Water Bath 12