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  5. Service Handbook

A.O. Smith 120 through 250 Series Service Handbook

Other manuals for 120 through 250 Series: Service Handbook, Installation, user and service manual
Manual is about: High Efficient Condensing Water Heater

Summary of 120 through 250 Series

  • Page 1

    1 service handbook printed in the u.S.A 0510 318349-000 servicing should only be performed by a qualified service agent. Commercial gas water heaters installation considerations - pre service checks - water heater construction - operation & service - troubleshooting 500 tennessee waltz parkway ashla...

  • Page 2: Commercial Gas Water Heater

    2 servicing should only be performed by a qualifi ed service agent introduction ............................................................3 qualifications ...........................................................3 service warning........................................................3 service r...

  • Page 3: Introduction

    3 servicing should only be performed by a qualifi ed service agent introduction introduction this service manual is designed to be an aid in servicing and troubleshooting a. O. Smith master-fit models btr 500 series 120/121 commercial water heaters. The instructions and illustrations contained in th...

  • Page 4: Requirements

    4 servicing should only be performed by a qualifi ed service agent requirements requirements instruction manual have a copy of the instruction manual that came with the water heater on hand for the model being serviced. Instruction manuals can be obtained at the a. O. Smith web site (www.Hotwater.Co...

  • Page 5: Installation Considerations

    5 servicing should only be performed by a qualifi ed service agent installation considerations installation considerations installation information given in this service manual is not a complete installation instruction. Installation information covered in this service manual has a limited focus as ...

  • Page 6

    6 servicing should only be performed by a qualifi ed service agent installation considerations air requirements carefully review the requirements for combustion and ventilation air in the instruction manual that came with the water heater. Failure to meet these requirements when the water heater is ...

  • Page 7

    7 servicing should only be performed by a qualifi ed service agent installation considerations insufficient make-up air, negative air pressure, and downdrafts a lack of combustion and ventilation air can create a negative ambient air pressure in the installed space. The vent system on one or more ga...

  • Page 8

    8 servicing should only be performed by a qualifi ed service agent installation considerations make-up air: direct communication with outdoors a fresh supply of make-up air for combustion can be supplied to the water heater through make-up air ducts, which directly communicate with the outdoors. (no...

  • Page 9

    9 servicing should only be performed by a qualifi ed service agent installation considerations contaminated air carefully review the warnings concerning contaminated combustion and ventilation air in the instruction manual that came with the water heater. Combustion air that is contaminated can grea...

  • Page 10

    10 servicing should only be performed by a qualifi ed service agent installation considerations table 2 minimum clearances to combustible surfaces “a” - right side “b” - left side “c” - back 5” (12.7 cm) 5” (12.7 cm) 5” (12.7 cm) a, b, and c clearances to non-combustible surfaces is “0” inches. A 20...

  • Page 11

    11 servicing should only be performed by a qualifi ed service agent installation considerations venting the btr 500 water heater is classified by ansi as a category i (non-condensing, negative pressure venting) appliance. It is approved for type b vent. The blower (draft inducer) does not pressurize...

  • Page 12: Operation And Service

    12 servicing should only be performed by a qualifi ed service agent operation and service operation and service sequence of operation 1. Call for heat is activated when temperature sensed from thermistor probes falls below the thermostat setting. 2. Blower (draft inducer) is energized. 3. Ignition c...

  • Page 13

    13 servicing should only be performed by a qualifi ed service agent operation and service electrical sequence 1. Switch power on to unit. 2. Thermostat calls for heat. 3. Ignition control board performs diagnostic check on system components. 4. On completion of diagnostics check, the ignition contro...

  • Page 14

    14 servicing should only be performed by a qualifi ed service agent operation and service wiring diagram thermostat ignition board upper probe/ probe thermoplastic or equivalent. Must be replaced use only type 105 c if any of the original wire as supplied board, digital thermostat and controls. When...

  • Page 15

    15 servicing should only be performed by a qualifi ed service agent operation and service operating sequence - flow chart figure 11 power on call for heat self diagnostic check is performed (correct state of blower prover switch and eco is verified) (polarity , earth ground , and igniter presence ar...

  • Page 16

    16 servicing should only be performed by a qualifi ed service agent operation and service gas control valve this gas valve is a 24 volt ac combination-step opening valve. It includes two valves assembled in parallel, connected by a wiring harness. Note that the valves have fixed pressure regulation ...

  • Page 17

    17 servicing should only be performed by a qualifi ed service agent operation and service manifold pressure adjustment the main gas regulators are found beneath the silver or black cap screws. (natural gas valves have silver caps; propane valves have a black caps). Remove the caps to access the outl...

  • Page 18

    18 servicing should only be performed by a qualifi ed service agent operation and service gas control valve/burner area view honeywell gas valve main burner shield rollout shield radiation shield main burner with hot surface igniter (hsi) mounted figure 14 table 3 hot surface igniter (hsi) volts ac ...

  • Page 19

    19 servicing should only be performed by a qualifi ed service agent operation and service blower prover switch - settings vent connection exhaust/outlet blower prover switch blower (draft inducer) optional hot water outlet figure 15 table 4 blower prover switch table btr model pressure setting to cl...

  • Page 20

    20 servicing should only be performed by a qualifi ed service agent operation and service thermostat and ignition control board view figure 16.

  • Page 21

    21 servicing should only be performed by a qualifi ed service agent operation and service white rodgers integrated control - thermostat figure 17 white rodgers ignition control board figure 18 display led label display leds to upper temp. Probe to ignition control board to lower temp. Probe fuse pin...

  • Page 22

    22 servicing should only be performed by a qualifi ed service agent operation and service pre-service checklist use the following checklist before you begin servicing the water heater. 1. Have you removed the cover from the controls? • did you take notice of the status lights on the upper water heat...

  • Page 23: Troubleshooting

    23 servicing should only be performed by a qualifi ed service agent troubleshooting troubleshooting ignition control board: error codes the white rodgers ignition control board will display a flashing error code with an led light located on the upper left corner of the ignition control board (figure...

  • Page 24

    24 servicing should only be performed by a qualifi ed service agent troubleshooting 3 flashes blower prover (air pressure) switch failed to close its normally open contacts after blower (draft inducer) was energized. Blower will run indefinitely, waiting for the blower prover switch circuit to close...

  • Page 25

    25 servicing should only be performed by a qualifi ed service agent troubleshooting 4 check molex plug connector between igniter/flame sensor assembly and control board; also check flame sense (12 pin) plug connection at control board. 8 flashes igniter not sensed and/or water heater not grounded. 1...

  • Page 26

    26 servicing should only be performed by a qualifi ed service agent troubleshooting integrated heater control: display lights power energy cut off status call for heat reset status led status indication action calling for heat normal status. No action required. The eco (energy cut-off) has opened. •...

  • Page 27

    27 servicing should only be performed by a qualifi ed service agent troubleshooting test 1: 120 vac to heater check conditions: • no green display “power” led on. • plugs are in receptacles. • supply power breaker is not open. • on/off heater switch is on. E2 display leds ignition control board grou...

  • Page 28

    28 servicing should only be performed by a qualifi ed service agent troubleshooting test 2: polarity check conditions: no hot water • green “power” led is on. • tank is more than 5° f below temperature dial setting. • red ignition control board diagnostic led is flashing 6 times between pauses. • re...

  • Page 29

    29 servicing should only be performed by a qualifi ed service agent troubleshooting test 3: continuity check of high limit (eco) conditions: power on – no hot water • red, heater control “call for heat” led – on • red ignition control board diagnostic led – 4 flashes • note led flash code before res...

  • Page 30

    30 servicing should only be performed by a qualifi ed service agent troubleshooting test 4: upper temperature probe continuity check conditions: power on - water below temperature set point. • red, water heater control “reset status” led-off • “call for heat” led off. • test 4 upper temperature prob...

  • Page 31

    31 servicing should only be performed by a qualifi ed service agent troubleshooting test 5: calling for heat - no blower operation conditions: power on • plugs in receptacles • red “ call for heat” led - on • blower (draft inducer) off • note flash code on ignition control board diagnostic led. Wate...

  • Page 32

    32 servicing should only be performed by a qualifi ed service agent troubleshooting test 6: blower on, no ignition conditions: power on • plugs in receptacles • blower (draft inducer) operating • no power to hot surface igniter (hsi). Note led flash code. • blower exhaust blower prover switch blower...

  • Page 33

    33 servicing should only be performed by a qualifi ed service agent troubleshooting test 7: blower on, blower prover switch closed, no igniter operation conditions: power on, but no power to igniter • plugs in receptacles • blower (draft inducer) on • 24v at ignition board e1, pin 10 • 1 2 3 4 e4 pl...

  • Page 34

    34 servicing should only be performed by a qualifi ed service agent troubleshooting test 8: igniter heats, no main burner 24 v. E1 plug to pin 9 e1 plug to pin 12 figure 27 test 8 igniter heats......No main burner if......... Then............ Short heat up time of igniter check control box grounding...

  • Page 35

    35 servicing should only be performed by a qualifi ed service agent troubleshooting test 9: igniter heats, no main burner conditions: test 8 completed • turn off power • disconnect wires from gas valve • inlet outlet manifold pressure tap measure resistance between gas valve terminals (main valve so...

  • Page 36

    36 servicing should only be performed by a qualifi ed service agent troubleshooting test 10: main burner ignition for less than five seconds conditions: power on; plug connected • main burner ignites for approximately five seconds, then goes out. • tests 8 and 9 completed • note the flash code on th...

  • Page 37

    37 servicing should only be performed by a qualifi ed service agent troubleshooting test 11: water heater shutting off below setting conditions: main burner ignited • stored water is below temperature setting more than 5° f (tank average). • power off • plug disconnected from heater control board re...

  • Page 38

    38 servicing should only be performed by a qualifi ed service agent notes.

  • Page 39

    39 servicing should only be performed by a qualifi ed service agent notes.

  • Page 40

    Copyright © 2010 a.O. Smith corporation. All rights reserved. 500 tennessee waltz parkway, ashland city, tn 37015 technical support: 800-527-1953 • parts: 800-433-2545 • fax: 800-644-9306 www.Hotwater.Com.