A.O. Smith T-M50 ASME Service Manual

T-M50 / T-M50 ASME Service manual Ver. 1.05 1 CONFIDENTIAL T-M50 / T-M50 ASME On-Demand Water Heater Service manual T-M50 A.O. Smith Wa

T-M50 / T-M50 ASME Service manual Ver. 1.05 10 CONFIDENTIAL 7. Wiring diagram check points for diagnosis Check- point Parts and Description Co

T-M50 / T-M50 ASME Service manual Ver. 1.05 11 CONFIDENTIAL Check- point Parts and Description Color of wires Normal Range H1 Gas proportio

T-M50 / T-M50 ASME Service manual Ver. 1.05 12 CONFIDENTIAL 8. Resistance values of the temperature thermistors Resistance values at different

T-M50 / T-M50 ASME Service manual Ver. 1.05 13 CONFIDENTIAL 9. Operational flow chart Power supply ONOperat ion SW ONFAV&BV openPre-c

T-M50 / T-M50 ASME Service manual Ver. 1.05 14 CONFIDENTIAL 10. Component specifications 10-1. Burners……………………..…………………………………………………..…………………...

T-M50 / T-M50 ASME Service manual Ver. 1.05 15 CONFIDENTIAL 10-1. Burners Unit Part # #101 AOS Part # EM445 Checkpoint N/A Function There

T-M50 / T-M50 ASME Service manual Ver. 1.05 16 CONFIDENTIAL 10-2. Gas manifold Unit Part # Included in #114 AOS Part # EM302 (LP model) EM303

T-M50 / T-M50 ASME Service manual Ver. 1.05 17 CONFIDENTIAL 10-3. Fan motor Unit Part # #416 AOS Part # EKK25 Checkpoint G Function To pro

T-M50 / T-M50 ASME Service manual Ver. 1.05 18 CONFIDENTIAL 10-4. Gas valve assembly Unit Part # Included in #114 AOS Part # EM302 (LP model)

T-M50 / T-M50 ASME Service manual Ver. 1.05 19 CONFIDENTIAL 10-5. Flame rod Unit Part # #103 AOS Part # EKK0E Checkpoint I Function To det

T-M50 / T-M50 ASME Service manual Ver. 1.05 2 CONFIDENTIAL Table of Contents 1. Specifications………………………………………...…...………….……………………...…………………………

T-M50 / T-M50 ASME Service manual Ver. 1.05 20 CONFIDENTIAL 10-6. AFR rod Unit Part # #103 AOS Part # EKK0E Checkpoint I Function -Checks

T-M50 / T-M50 ASME Service manual Ver. 1.05 21 CONFIDENTIAL 10-7. Heat exchanger Unit Part # #401 (Regular model) #444 (ASME model) AOS Part #

T-M50 / T-M50 ASME Service manual Ver. 1.05 22 CONFIDENTIAL 10-8. Flow sensor Unit Part # #421 AOS Part # EKH33 Checkpoint H2 Function Det

T-M50 / T-M50 ASME Service manual Ver. 1.05 23 CONFIDENTIAL 10-9. Water control valve (flow adjustment valve and bypass valve) Unit Part # #41

T-M50 / T-M50 ASME Service manual Ver. 1.05 24 CONFIDENTIAL Blue-Brown 13.0 to 16.0 VDC Orange-Brown ON: 12.5 to 16.0 VDC OFF: 0 to 1 VD

T-M50 / T-M50 ASME Service manual Ver. 1.05 25 CONFIDENTIAL 10-10. Thermistors Unit Part # #424 (Inlet) #405 (Output) #430 (Mixing) AOS Part #

T-M50 / T-M50 ASME Service manual Ver. 1.05 26 CONFIDENTIAL 10-11. Hi-limit switch Unit Part # #403 AOS Part # EKN34 Checkpoint C1 Functio

T-M50 / T-M50 ASME Service manual Ver. 1.05 27 CONFIDENTIAL 10-12. Overheat cutoff fuse Unit Part # #402 AOS Part # EK333 Checkpoint C2 Fu

T-M50 / T-M50 ASME Service manual Ver. 1.05 28 CONFIDENTIAL 10-13. Freeze protection heaters Unit Part # #408 #425 #426 #441 AOS Part # EKN86 EX

T-M50 / T-M50 ASME Service manual Ver. 1.05 29 CONFIDENTIAL 10-14. Left/right computer boards Unit Part # #701 AOS Part # EM306 Checkpoint

T-M50 / T-M50 ASME Service manual Ver. 1.05 3 CONFIDENTIAL 1. Specifications Unit Model T-M50 / T-M50 ASME Unit dimensions H25.3"×W

T-M50 / T-M50 ASME Service manual Ver. 1.05 30 CONFIDENTIAL 10-15. Central computer boards Unit Part # #702 AOS Part # EM307 Checkpoint N/

T-M50 / T-M50 ASME Service manual Ver. 1.05 31 CONFIDENTIAL 10-16. Transformer Unit Part # #718 AOS Part # EM296 Checkpoint A1,A2 Function

T-M50 / T-M50 ASME Service manual Ver. 1.05 32 CONFIDENTIAL 10-17. GFI Unit Part # #720 AOS Part # EM207 Checkpoint A,A1 Function -Detects

T-M50 / T-M50 ASME Service manual Ver. 1.05 33 CONFIDENTIAL 10-18. Igniter Unit Part # #102 AOS Part # EKN74 Checkpoint B Function -To ign

T-M50 / T-M50 ASME Service manual Ver. 1.05 34 CONFIDENTIAL 10-19. Freeze protection thermostat Unit Part # #140 AOS Part # EM286 Checkpoin

T-M50 / T-M50 ASME Service manual Ver. 1.05 35 CONFIDENTIAL 10-20. Surge box Unit Part # #722 AOS Part # EM385 Checkpoint A2,A3 Function P

T-M50 / T-M50 ASME Service manual Ver. 1.05 36 CONFIDENTIAL 11. Fault Analysis & Specifications Remarks: 1. Proper range of values of voltag

T-M50 / T-M50 ASME Service manual Ver. 1.05 37 CONFIDENTIAL Natural of Fault Diagnosis Checkpoint ・The hot water is not available when

T-M50 / T-M50 ASME Service manual Ver. 1.05 38 CONFIDENTIAL Natural of Fault Diagnosis Checkpoint 4 Fault of Left and/or Right PCB [1] No vol

T-M50 / T-M50 ASME Service manual Ver. 1.05 39 CONFIDENTIAL Error Code Diagnosis Checkpoint 101 8 Check if there is dust and lint in burner an

T-M50 / T-M50 ASME Service manual Ver. 1.05 4 CONFIDENTIAL 5" (127mm)24-7/8" (632 .9mm)25-1/4" (642mm)7-3/8" (186mm) GAS1-5/

T-M50 / T-M50 ASME Service manual Ver. 1.05 40 CONFIDENTIAL Error Code Malfunction description Cancellation method Loss of flame Turn off t

T-M50 / T-M50 ASME Service manual Ver. 1.05 41 CONFIDENTIAL Error Code Diagnosis Checkpoint 5 Disconnected/damaged O.H.C.F. (Refer to

T-M50 / T-M50 ASME Service manual Ver. 1.05 42 CONFIDENTIAL Error Code Malfunction description Cancellation method Disconnected AFR rod Turn

T-M50 / T-M50 ASME Service manual Ver. 1.05 43 CONFIDENTIAL Error Code Malfunction description Cancellation method Fault of driving circuit

T-M50 / T-M50 ASME Service manual Ver. 1.05 44 CONFIDENTIAL Error Code Malfunction description Cancellation method Pump failure Turn off the

T-M50 / T-M50 ASME Service manual Ver. 1.05 45 CONFIDENTIAL Error Code Malfunction description Cancellation method 1 Fault of Left and/or Righ

T-M50 / T-M50 ASME Service Manual Ver. 1.05 46 CONFIDENTIAL Error Code Malfunction description Cancellation method Miscommunication between

T-M50 / T-M50 ASME Service Manual Ver. 1.05 47 CONFIDENTIAL 12. Controls and settings 12-1. Diagnosis using the remote controller…………………….…….……

T-M50 / T-M50 ASME Service Manual Ver. 1.05 48 CONFIDENTIAL 12-1. Diagnosis using the remote controller < Individual unit> 1. Press th

T-M50 / T-M50 ASME Service Manual Ver. 1.05 49 CONFIDENTIAL < For multiple units in the Multi-unit system and the Easy-Link system > 1.

T-M50 / T-M50 ASME Service manual Ver. 1.05 5 CONFIDENTIAL 3. Interior view 14 4552267678891011121213141516161718181

T-M50 / T-M50 ASME Service Manual Ver. 1.05 50 CONFIDENTIAL Description of mode numbers in “Diagnostics Mode” Mode # Whole multi-unit system inf

T-M50 / T-M50 ASME Service Manual Ver. 1.05 51 CONFIDENTIAL 12-2. Displaying error codes If the T-M50 is undergoing abnormal conditions, the co

T-M50 / T-M50 ASME Service Manual Ver. 1.05 52 CONFIDENTIAL B. With easy-link system installations: Example: If Unit #2 fails on the “321” error

T-M50 / T-M50 ASME Service Manual Ver. 1.05 53 CONFIDENTIAL C. With multi-unit system installations: Example: If Unit #2 fails on the “321” erro

T-M50 / T-M50 ASME Service Manual Ver. 1.05 54 CONFIDENTIAL 12-3. The error-code button: Verifying functionality of computer board, Displaying e

T-M50 / T-M50 ASME Service Manual Ver. 1.05 55 CONFIDENTIAL 12-4. Clearing the “101” and “991” error code The “101” and “991” error codes signi

T-M50 / T-M50 ASME Service Manual Ver. 1.05 56 CONFIDENTIAL 12-5. AFR rod function <Function> The AFR rod checks flame conditions during

T-M50 / T-M50 ASME Service Manual Ver. 1.05 57 CONFIDENTIAL 12-6. Dipswitch settings of the left/right computer boards The T-M50 shares the

T-M50 / T-M50 ASME Service Manual Ver. 1.05 58 CONFIDENTIAL 12-7. Dipswitch settings of the central computer board There are two banks of dipsw

T-M50 / T-M50 ASME Service Manual Ver. 1.05 59 CONFIDENTIAL The functions of the lower dipswitch bank No. Functions and Dipswitch settings 1 2

T-M50 / T-M50 ASME Service manual Ver. 1.05 6 CONFIDENTIAL 4. List of main components in the interior view No. Description Items# in compone

T-M50 / T-M50 ASME Service Manual Ver. 1.05 60 CONFIDENTIAL 12-8. Assigning unit numbers in the Easy-link system A. How to display the unit n

T-M50 / T-M50 ASME Service Manual Ver. 1.05 61 CONFIDENTIAL 12-9. (A) ON/OFF conditions: Overview The following table shows the ON/OFF conditio

T-M50 / T-M50 ASME Service Manual Ver. 1.05 62 CONFIDENTIAL 12-9. (B) ON/OFF conditions: BTU requirements A. Calculating the ON/OFF conditions

T-M50 / T-M50 ASME Service Manual Ver. 1.05 63 CONFIDENTIAL 12-10. Conditions that stop the T-M50 from operating <About the dual combustion

T-M50 / T-M50 ASME Service Manual Ver. 1.05 64 CONFIDENTIAL 12-11. Pump control ON/OFF Conditions To run circulation pumps efficiently an

T-M50 / T-M50 ASME Service Manual Ver. 1.05 65 CONFIDENTIAL 12-12. Multi-unit system ON/OFF conditions In Easy-link system and Multiple-sys

T-M50 / T-M50 ASME Service Manual Ver. 1.05 66 CONFIDENTIAL 3. Example: Output set temperature = 120˚F in a four-unit system and priority unit

T-M50 / T-M50 ASME Service Manual Ver. 1.05 67 CONFIDENTIAL 12-13. Operation time for unit rotation The T-M50 contains two combustion sectio

T-M50 / T-M50 ASME Service Manual Ver. 1.05 68 CONFIDENTIAL 12-14. Individual unit operation in multiple-system while multi-unit control

T-M50 / T-M50 ASME Service Manual Ver. 1.05 69 CONFIDENTIAL 12-15. High-Altitude Region Support Functions (FM+, FM++, FM+++ and INPUT-) ＜Using

T-M50 / T-M50 ASME Service manual Ver. 1.05 7 CONFIDENTIAL No. Description Items# in components diagram Takagi Part # Common parts For other

T-M50 / T-M50 ASME Service Manual Ver. 1.05 70 CONFIDENTIAL 12-16. Alarm port terminal This function is to alert end-users of any error codes

T-M50 / T-M50 ASME Service Manual Ver. 1.05 - 71 - CONFIDENTIAL 12-17. How to use the “External fan control” (Only on Parent Unit） The extern

T-M50 / T-M50 ASME Service Manual Ver. 1.05 72 CONFIDENTIAL 12-18. Relay selection for the pump control connection The maximum current capacit

T-M50 / T-M50 ASME Service Manual Ver. 1.05 73 CONFIDENTIAL 12-19. Adjusting manifold gas pressure The manifold gas pressure on the T-M50 can b

T-M50 / T-M50 ASME Service Manual Ver. 1.05 74 CONFIDENTIAL 5. Press and hold down the “MIN” button on the computer board. While

T-M50 / T-M50 ASME Service Manual Ver. 1.05 75 CONFIDENTIAL 12345678NO12-20. Manually adjusting the fan motor speed While the FM+ dipswitch w

T-M50 / T-M50 ASME Service Manual Ver. 1.05 76 CONFIDENTIAL 12-21. Freeze protection system There are two features to the T-M50’s freeze protec

T-M50 / T-M50 ASME Service Manual Ver. 1.05 77 CONFIDENTIAL <Deactivate condition> When the computer checks for these temperatures during

T-M50 / T-M50 ASME Service Manual Ver. 1.05 78 CONFIDENTIAL Automatic firing system Activation conditions will depend on the on whether or it i

T-M50 / T-M50 ASME Service Manual Ver. 1.05 79 CONFIDENTIAL 12-22. Freeze protection for recirculation systems <Function and Purpose> T

T-M50 / T-M50 ASME Service manual Ver. 1.05 8 CONFIDENTIAL 5. Schematic diagram 1. When a hot water tap is opened,

T-M50 / T-M50 ASME Service Manual Ver. 1.05 80 CONFIDENTIAL 12-23. Draining the unit and cleaning the inlet water filter 1. Close the manual

T-M50 / T-M50 ASME Service Manual Ver. 1.05 81 CONFIDENTIAL 709416705707 706708704418 703715701719113708702710712713711714113711113 113 71641670

T-M50 / T-M50 ASME Service Manual Ver. 1.05 82 CONFIDENTIAL Burner assembly 11411511670511311311770770710212111911870770710911210611110511311310

T-M50 / T-M50 ASME Service Manual Ver. 1.05 83 CONFIDENTIAL Combustion and Exhaust assembly Other than Part# 444, Part# 445, Part# 446 and Part#

T-M50 / T-M50 ASME Service Manual Ver. 1.05 84 CONFIDENTIAL T-M50 T-M50 ASME 4224194114194114244064074194114254274234074064254274114194114194224

T-M50 / T-M50 ASME Service Manual Ver. 1.05 85 CONFIDENTIAL 14. Parts list Item # Part # Description Common parts for other models 1 EM305

T-M50 / T-M50 ASME Service Manual Ver. 1.05 86 CONFIDENTIAL Item # Part # Description Common parts for other models 110 EKK0G Burner holder

T-M50 / T-M50 ASME Service Manual Ver. 1.05 87 CONFIDENTIAL Item # Part # Description Common parts for other models 131 EM267 Exhaust gaske

T-M50 / T-M50 ASME Service Manual Ver. 1.05 88 CONFIDENTIAL Item # Part # Description Common parts for other models 416 EKK25 Fan motor T-K

T-M50 / T-M50 ASME Service Manual Ver. 1.05 89 CONFIDENTIAL Item # Part # Description Common parts for other models 441 EKN67 Heater 117

T-M50 / T-M50 ASME Service manual Ver. 1.05 9 CONFIDENTIAL 6. Wiring diagram BK:BLACKP:PURPLELB:LIGHT BLUEBL:BLUEG;GREENY:YELLOWO:ORANGEBR:

T-M50 / T-M50 ASME Service Manual Ver. 1.05 90 CONFIDENTIAL Item # Part # Description Common parts for other models 713 EM262 Right communi

T-M50 / T-M50 ASME Service Manual Ver. 1.05 91 CONFIDENTIAL 15. Records of revision of this manual Version Changes Date 1.00 First edition