A.O. Smith 120 through 250 Series Specifications

MODELS COVERED: BTH 120 THRU 500 SERIES 100, 101 AND BTH 400/500 SERIES 104500 Tennessee Waltz ParkwayAshland City, TN 37015PRINTED IN THE U.S.A. 10

8Servicing should only be performed by a Qualied Service TechnicianINSTALLATION QUICK TIPS – BTH 300, 400, 500 GAS PRESSUREADJUSTMENT PROCEDURE: MANI

9Servicing should only be performed by a Qualied Service TechnicianINSTALLATION QUICK TIPS – BTH 300, 400, 500SEE MANUAL FOR COMPLETE INSTALLATION IN

10Servicing should only be performed by a Qualied Service TechnicianINSTALLATION – VENTING CATEGORY AND MATERIALSCYCLONE VENTINGCategory IV • Positi

11Servicing should only be performed by a Qualied Service TechnicianVENTING TABLES – BTH 120 ‑ 250Maximum equivalent feet of intake and vent pipe usi

12Servicing should only be performed by a Qualied Service TechnicianCONCENTRIC VENTINGConcentric venting allows for a single wall penetration. For mu

13Servicing should only be performed by a Qualied Service TechnicianVENT CONDENSATION4” PIPE FIELDSUPPLIEDEXHAUST ELBOWVENT CONNECTIONFACTORY INSTALL

14Servicing should only be performed by a Qualied Service TechnicianVENTING – ALL MODELS – SINGLE PIPE DIRECT VENT – USING OUTSIDE AIR TERMINATION CL

15Servicing should only be performed by a Qualied Service TechnicianVENTING – ALL MODELS – TWO PIPE DIRECT VENT – USING OUTSIDE AIR TERMINATION CLEAR

16Servicing should only be performed by a Qualied Service TechnicianVENT TERMINATION – DIRECT VENT – ALL MODELSWHEN LOCATING THE TERMINALS ON A SIDEW

17Servicing should only be performed by a Qualied Service TechnicianDIRECT VENTING – ALL MODELSThe air intake provided on the unit contains an air in

18Servicing should only be performed by a Qualied Service TechnicianCONTROL OVERVIEWInteraction with the water heater controller is through an LCD di

19Servicing should only be performed by a Qualied Service TechnicianThe table of status icons describes graphically operational details of the water

20Servicing should only be performed by a Qualied Service TechnicianADJUSTING TANK TEMPERATURE – OPERATING SET POINT – DIFFERENTIALThe Operating Set

21Servicing should only be performed by a Qualied Service TechnicianACTION:Press Change then use the UP and DOWN buttons to change the Operating Set

22Servicing should only be performed by a Qualied Service TechnicianCHANGING THE DISPLAY UNITSThe desktop menu Display Settings has the option of sel

23Servicing should only be performed by a Qualied Service TechnicianACTION:Press Update to accept the change or Cancel to reject it.DISPLAY:

24Servicing should only be performed by a Qualied Service TechnicianFAULT AND WARNING CONDITIONS – ADVANCED DIAGNOSTIC INFORMATIONThis water heater c

25Servicing should only be performed by a Qualied Service TechnicianACCESS TO THE CURRENT FAULT OR WARNINGWhen a fault or warning has been detected b

26Servicing should only be performed by a Qualied Service TechnicianFAULT CODESAll faults, warnings, and errors are given in plain English text. Some

27Servicing should only be performed by a Qualied Service TechnicianVIEWING THE FAULT HISTORY – VIEWING INFORMATION ABOUT THE HEATERThe controller fo

1Servicing should only be performed by a Qualied Service TechnicianTABLE OF CONTENTSINTRODUCTION ...

28Servicing should only be performed by a Qualied Service TechnicianCONTROL SEQUENCE (TYPICAL ALL MODELS)TYPICAL SEQUENCE1. When the control is powe

29Servicing should only be performed by a Qualied Service TechnicianCONTROL SEQUENCE FLOW CHART

30Servicing should only be performed by a Qualied Service TechnicianCONTROLS – CENTRAL CONTROL BOARD – CCBThe Central Control Board or CCB is contain

31Servicing should only be performed by a Qualied Service TechnicianThis is the back of the UIM.

32Servicing should only be performed by a Qualied Service TechnicianCONTROLS – GAS CONTROL VALVE BTH 120The gas control valve on the BTH 120 has a bu

33Servicing should only be performed by a Qualied Service TechnicianCONTROLS – GAS CONTROL VALVE BTH 199 AND 250Pressure readings may be taken on the

34Servicing should only be performed by a Qualied Service TechnicianCONTROLS – GAS CONTROL VALVE, ORIFICE CHART ‑ BTH 300/400 ‑ 100/101The gas contro

35Servicing should only be performed by a Qualied Service TechnicianCONTROLS – GAS CONTROL VALVE, ORIFICE CHART – BTH 400/500The gas control valve ha

36Servicing should only be performed by a Qualied Service TechnicianCONTROLS – PRESSURE SWITCHES – ALL MODELSAll BTH models are provided with four pr

37Servicing should only be performed by a Qualied Service TechnicianCONTROLS – PRESSURE SWITCHES – BTH 120 THROUGH 250Note: Check the website www.hot

2Servicing should only be performed by a Qualied Service TechnicianINTRODUCTIONThe service handbook is designed to aid in servicing and troubleshooti

38Servicing should only be performed by a Qualied Service TechnicianCONTROLS – PRESSURE SWITCHES – BTH 300, 400, 500Note: Check the website www.hotwa

39Servicing should only be performed by a Qualied Service TechnicianCONTROLS – CONNECTIONS, IGNITER, FLAME SENSOR, SIGHT GLASS, POWERED ANODESThe con

40Servicing should only be performed by a Qualied Service TechnicianHOT SURFACE IGNITER / FLAME SENSOR / CONTROL TIMINGHOT SURFACE IGNITERThis water

41Servicing should only be performed by a Qualied Service TechnicianBLOWER SPEED CONTROL BTH 199 AND 250The input of the BTH 199 and BTH 250 is deter

42Servicing should only be performed by a Qualied Service TechnicianVARIABLE FREQUENCY DRIVE – BTH 400 AND 500The Cyclone Xi BTH 400 and 500 models h

43Servicing should only be performed by a Qualied Service TechnicianVARIABLE FREQUENCY DRIVE – BLOWER SPEED AND PRESSURE READINGSThe instructions for

44Servicing should only be performed by a Qualied Service TechnicianWIRING DIAGRAM – BTH 120 ‑ 300

45Servicing should only be performed by a Qualied Service TechnicianWIRING DIAGRAM – BTH 400, 500

46Servicing should only be performed by a Qualied Service TechnicianNOTES

47Servicing should only be performed by a Qualied Service TechnicianNOTES

3Servicing should only be performed by a Qualied Service TechnicianTOOLS REQUIRED• ELECTRICAL MULTIMETER CAPABLE OF MEASURING CONTINUITY/ OHMS, AC &

Visit the "Information Central" link of www.hotwater.com for a listing of available Service Handbooks. For additional information contact:

4Servicing should only be performed by a Qualied Service TechnicianGENERAL INFORMATIONINSTALLATION REQUIREMENTS FOR THE COMMONWEALTH OF MASSACHUSETTS

5Servicing should only be performed by a Qualied Service TechnicianGAS SUPPLY SYSTEMSLow pressure building gas supply systems are defined as those sy

6Servicing should only be performed by a Qualied Service TechnicianINSTALLATION QUICK TIPS – BTH 120 AND 150: GAS PRESSUREADJUSTMENT PROCEDURE: MANIF

7Servicing should only be performed by a Qualied Service Technician2. “Clock” the meter as in step (2) above.3. Repeat steps (1) and (2) until the