Ultra Low NOx Atmospheric Vent Gas Water Heaters SERVICE MANUAL Troubleshooting Guide and Instructions for Service (To be performed ONLY by qualified service providers) Models Covered by This Manual: U65L155E*N (A) U65L199E*N (A) U65L270E*N (A) U100L199E*N (A) U100L270E*N (A) U100L300E*N (A) U100L399E*N (A) (*) Denotes Warranty Years Manual 238-50129-00A Save this manual for future reference
The Bradford White Table of Contents Page Service Procedure Introduction 3 --- How to use this manual 4 --- Tool required for service 4 --- Features 5 --- Specifications 6 --- Sequence of Operation 8 --- Troubleshooting 10 --- Thermostat Circuit, Testing & Replacement 27 I Combustion System Testing and Replacement 31 II Burner Tube Inspection & Replacement 35 III Gas Valve Replacement 37 IV Blower Testing and Replacement 38 V Flame Sensor Testing and Replacement 40 V
Introduction The Bradford White Ultra Low NOx Atmospheric Vent Water Heater is designed to deliver a remarkable amount of hot water at 84% efficient in a quiet running unit with a low vent connection that allows for installation existing locations. Several technologically advanced design features are incorporated in the design that will require additional knowledge on the part of the qualified service provider.
It is intended for this manual to be used by qualified service personal for the primary purpose of troubleshooting analysis and repair of the Bradford White Ultra Low NOX Atmospheric Vent Water Heater. Understanding the sequence of operation section of this manual will contribute greatly to troubleshooting this product. A “Service Report” is shown towards the end of this manual. Completing this form will assist in the troubleshooting efforts.
Features of Honeywell Integrated Control System Attractive digital water heater display on control panel for setting and displaying the temperature setpoint. Pressing temperature UP and DOWN buttons changes the temperature setpoint. Same water heater display used on all models. Temperature format may be displayed in °F or °C. Single control board with plug in wiring controls temperature, ignition, and blower operation. Reduced number of parts for servicing and wiring.
Dimensional Layout Model Description Model Number Capacity (GAL) U65L155E3N(A) U65L199E3N(A) U65L270E3N(A) U100L199E3N(A) U100L270E3N(A) U100L300E3N(A) U100L399E3N(A) 65 65 65 100 100 100 100 Input BTU/Hr. NAT. 155,000 199,999 270,000 199,999 270,000 300,000 399,999 1st Hour Delivery at 100°F Rise (Gal.) 203 249 320 274 345 375 477 C B A Floor to Vent Floor to Top of Dia. Vent (in) Cold Water (in.) Conn.
Honeywell Integrated Control System Power supply Gas Supply Dedicated 120 VAC, 60 Hz, 15A Minimum ¾”NPT for 300,000 BTU’s/hr. and below. Minimum 1" NPT for 399,999 BTU’s/hr. (schedule 40 black iron pipe recommended) Approved Gas Type Natural gas only. Gas supply must match the gas type listed on the water heater rating label. Gas Pressure (Nat.) 14.0" W.C. maximum static, 4.5" W.C. minimum running (recommend 7.0" W.C.
For models with Honeywell Integrated Control System w/ Direct Spark Ignition 1 Thermostat calls for heat. 2 Combustion blower & circulator start while the damper opens. 3 Blower pre-purge period of 30 seconds. 4 Trial for Ignition. (5 seconds, 3 trials). Flame establishing period (3 seconds), gas valve opens, sparks from spark rod to burner surface to ignite the gas. Burner on, flame proving period (2 seconds). Requires a minimum of 0.8 microamp through flame sense rod to prove flame.
For models with Honeywell Integrated Control System w/ Direct Spark Ignition Lockout Conditions (Complete list of error codes is listed on the unit) The system will go into lock out mode for the following reasons: 1. ERROR CODE 26 If the blocked vent safety switch mounted on the draft hood should open, the gas valve will close, the blower will post-purge and error code 26 will appear on the display. The lockout condition will reset once the problem is corrected and the switch reset.
System Observation For models with Direct Spark Ignition Water Heater Fault: Water heater does not operate Display Error Code: Water heater display does not operate - blank display WARNING 120 volt potential exposure. Use caution making voltage checks to avoid personal injury. Check main power supply to water heater - fuse, circuit breaker, plug receptacle, line cord or wiring to water heater.
System Observation For models with Direct Spark Ignition WARNING 120 volt potential exposure. Use caution making voltage checks to avoid personal injury. From previous page CAUTION Use caution not to damage connectors when making voltage measurements or jumping terminals Error code #29 on display. Refer to Control Board illustration. Measure voltage between terminals P7(3) & P7(5) on the “inducer” output (make sure the control display shows “heating” in the status mode, if not increase the setpoint).
Accessing Service Mode on Control Display For models with Honeywell Integrated Control The display has a “service mode” for changing the maximum setpoint and accessing information in aiding servicing of the water heater. This procedure is for service and installation personnel only. To enter the Service Mode, follow the steps illustrated below: Step 1: Press “Select” and “Temperature Up” buttons together and hold for 3 seconds until “Max Setpoint” is shown in the display.
Accessing Service Mode on Control Display For models with Honeywell Integrated Control 1. Max Setpoint (Display/Change) Max Setpoint value in Water Heater Display Max Setpoint °F idle Status Operational & SELECT SET 2. Tank Sensor Temperature Displayed Water Temperature Average. °F Water Temp idle Status Operational SELECT SET 3.
Accessing Service Mode on Control Display For models with Honeywell Integrated Control 4. Setpoint (Display/Change) °F setpoint idle Status Operational SELECT SET 5. °F/°C (Display/Change) °F °F/C° setpoint idle Status Operational SELECT SET 6.
Accessing Service Mode on Control Display For models with Honeywell Integrated Control 7. Software Version (Display only) Soft idle Status Operational & SELECT SET 8. Error Code History (Displays if there are present error codes or up to 10 previous error codes see page 22). Water Heater Display will show a “--“ if there are no error codes.
Accessing Service Mode on Control Display For models with Honeywell Integrated Control Step 2: Press “Set” button to enter setting mode. “Max Setpoint” will flash to indicate setting mode. "Max Setpoint" Flashes °F Max Setpoint idle Status Operational % SELECT SET Step 3: Press the “UP” or “DOWN” buttons to change the maximum setpoint value. This will limit the maximum setpoint the user can select. Note: The maximum setpoint is approximately 180°F.
Accessing Service Mode on Control Display For models with Honeywell Integrated Control Step 5: 30 Seconds after the last button press, the Water Heater Display will go back to “User Mode”. It will read “Max Setpoint” without showing a temperature value if the temperature setpoint is at the maximum setting. The Water Heater Display can be set back to the “User Mode” immediately by pressing both the “Temperature Up” and “Select” buttons together for 3 seconds.
Accessing Service Mode on Control Display For models with Honeywell Integrated Control To Display Flame Sense Current of the Pilot Flame Sensor: The pilot flame sense current is available only when the burners are in operation. Step 1: Make sure the status displays “Heating” or draw enough hot water to start the burners. Step 2: Enter the “Service Mode” described previously. Step 3: Press the “Select” button until a number value is displayed with “Flame Current” to the right of the number.
Accessing Service Mode on Control Display For models with Honeywell Integrated Control Step 2: Press the “Set” button to enter the setting mode. “Setpoint” will flash in the water heater display. °F setpoint idle Status Operational SELECT SET Step 3: To raise the temperature setpoint, press the “Temperature Up” button until the desired temperature is shown on the water heater display.
Accessing Service Mode on Control Display For models with Honeywell Integrated Control Step 5: When the desired setpoint is reached on the water heater display, press the “Set” button to confirm the new setpoint. “Setpoint” stops flashing in the water heater display.
Accessing Service Mode on Control Display For models with Honeywell Integrated Control Step 3a: Press “Temperature Up” button to change temperature format to °C °C °F/C° idle Status Operational SELECT SET % Step 3b: Press “Temperature Down” button to change temperature format to °F °F °F/C° idle Status Operational SELECT SET Step 4: Press “Set” button to confirm °F or °C format.
Accessing Service Mode on Control Display For models with Honeywell Integrated Control Step 5: Pressing “Select” button will return display to setpoint in format selected (°F or °C) immediately °F idle Status Operational Lower Sensor SELECT SET Error Codes and Error History Display: If there is an operating problem with the water heater, an error code number will appear on the water heater display with “Service Needed” to the right of the “Status” indicator.
Accessing Service Mode on Control Display For models with Honeywell Integrated Control To view previous error codes: Step 1: In “Service Mode press the “Select” button until the next display after the “Software Version”. If there are no current error codes, the display will show -- . °F idle Status Operational SELECT SET Step 2: Press the “Temperature Down” button to select the error code index, starting with the most recent error code “10”.
Accessing Service Mode on Control Display For models with Honeywell Integrated Control Step 4: Press the “Temperature Down” button to change to the previous code index, code #9. idle Status Operational SELECT SET % Step 5: Press the “Select” button for code index #9 to view if there are any code numbers.
Error Code Definitions For models with Honeywell Integrated Control ERROR CODE DEFINITIONS If the water heater has an operating problem, there will be a number in the water heater display with “Service Needed” shown below the error code number. Note the error code and the definition in the chart below. This label appears on the control box under the water heater display. The following sections will provide instructions for servicing each error code.
Resetting Error Codes For models with Honeywell Integrated Control WARNING The following procedure is for service and installation personnel only. Resetting lockout conditions without correcting the malfunction can result in a hazardous condition. If an error code is displayed (except for #4, low flame sense current), the water heater will be in a “lockout condition” with the water heater display showing the error code number and “Service Needed” in the status section of the display window.
WARNING 120 volt potential exposure. Use caution making voltage checks to avoid personal injury. IMPORTANT NOTE: This procedure assumes a cool tank CAUTION Use caution not to damage connectors when making voltage measurements or jumping terminals Condition: Water Heater Not Operating Display shows error code “32” ( Sensor Reading Faulty) Unplug or disconnect electrical power to the water heater Check continuity of wire harness to sensor. Resistance of harness should be close to 0 ohms.
Condition: Water Heater Not Operating Display shows error code “65” High Water Temperature (over 200 °F) (Continued from previous page) WARNING Do not operate water heater without verifying that the overheating condition has been corrected. Once cause of overheating condition has been diagnosed and corrected, the control may be reset Reconnect and switch on power to the water heater.
APPENDIX - A Sensor Resistance at Various Temperatures Be Careful When Making Voltage Measurements or Jumping Terminals Not to Damage or Deform Connectors or Connector Pins. Draw Water From The T&P Valve. Compare Temperature With Temperature Ohms Chart Below. Example: If temperature of sensor is 84°F, then the resistance through the sensor would be 8449 (see shaded area). NOTE: Sensor resistance increases as the temperature falls.
Thermostat Sensor (Thermister) Replacement Procedure WARNING 120 volt potential exposure. Isolate the appliance and reconfirm power is disconnected using a multi-meter. Step 1. Position main power switch to “OFF” Step 2. Disconnect (unplug) water heater from 120 volt power source. Step 3. Un-latch and remove top surround cover from top of heater. Step 4. Unclip sensor connector from control board and remove harness from control panel (see picture). Step 5.
Observe burner operation through the sight glass located on the combustion insert mounting flange. Normal burner operation should ignite smoothly, without evidence of coughing or huffing upon ignition. The burner flame should be a blue flame near the burner surface in a uniform flame pattern. Occasional yellow or white streaks are normal. Note: Models using metal fiber mesh burner a red glow from the burner surface is normal. Verify Minimum Gas Supply Piping Requirements of: Minimum ¾" NPT.
Observe burner operation through the sight glass located on the combustion insert mounting flange. Normal burner operation should ignite smoothly, without evidence of coughing or huffing upon ignition. The burner flame should be a blue flame near the burner surface in a uniform flame pattern. Occasional yellow or white streaks are normal. WARNING 120 volt potential exposure. Isolate the appliance and reconfirm power is disconnected using a multi-meter.
WARNING Heater components may be HOT when performing the following steps in this procedure. Take necessary precaution to prevent personal injury. Combustion System Removal Procedure Step 1. Position main power switch to “OFF”. Step 2. Disconnect (unplug) water heater from 120 volt power source. Step 3. Turn off gas supply to water heater. Step 4. Un-latch and remove surround cover from top of heater. Step 5.
Combustion System Replacement Procedure Step 1. Fully inspect burner gasket for the following: a) Tears d) Dirt or debris b) Missing material e) Other imperfections that would inhibit proper seal c) Cracks If gasket is NOT affected by any of the above, gasket replacement is not required. Step 2. Install combustion system using new gasket or fully inspected gasket from step 1. Secure the combustion system to the threaded studs using nuts from step 10 on previous page. Tighten the nuts evenly Step 3.
WARNING Heater components may be HOT when performing the following steps in this procedure. Take necessary precaution to prevent personal injury. Burner Tube Removal Procedure Step 1. Position main power switch to “OFF”. Step 2. Disconnect (unplug) water heater from 120 volt power source. Step 3. Turn off gas supply to water heater. Step 4. Un-latch & remove surround cover from top of heater. Step 5.
WARNING Heater components may be HOT when performing the following steps in this procedure. Take necessary precaution to prevent personal injury. Burner Tube Inspection Step 1. a) Outer fiber mesh should be uniform with no tears or deterioration. b) Gently squeeze burner tube, Burner tube should feel firm without any soft areas around the sides or at the bottom. c) Visually inspect inside burner tube, Burner tube should be intact with no areas of deterioration. Ports should be free of any debris. Step 2.
Gas Valve Replacement Procedure Step 1. Position main power switch to “OFF”. Step 2. Disconnect (unplug) water heater from 120 volt power source. Step 3. Turn off gas supply to water heater. Step 4. Un-latch & remove surround cover from top of heater. Step 5. From the gas valve, disconnect the gas connection, PVC damper assembly, silicone tubing and wire harness. Step 6.
Is there 120VAC across the white and black wires at location P3 on the control board ? (see photo at bottom) Does blower energize? Y (For Direct Spark Ignition models, ensure control display shows “Heating”, raise temperature setpoint if necessary) Refer to ignition module/control board illustration. Is there 120VAC between P7(5) and P7(3)? Y N Y Black wire leading to control board from power switch looped through amprobe.
Blower Replacement Procedure WARNING 120 volt potential exposure. Isolate the appliance and reconfirm power is disconnected using a multi-meter. Step 1. Position main power switch to “OFF”. Step 2. Disconnect (unplug) water heater from 120 volt power source. Step 3. Turn off gas supply to water heater. Step 4. Un-latch & remove surround cover from top of heater. Step 5. From the gas valve, disconnect the gas connection, PVC damper assembly, silicone tubing and wire harness.
WARNING Flame Sensor Testing Procedure Refer to illustration below, is there a minimum of 1 micro amp during 1.5 second flame proving period? 120 volt potential exposure. Use caution making voltage checks to avoid personal injury. Flame sensor may be too hot to handle, take necessary precautions Refer to ignition module/control board illustration.(24 volts should maintain beyond the 1.5 second flame proving period.
Flame Sensor Replacement Procedure WARNING 120 volt potential exposure. Isolate the appliance and reconfirm power is disconnected using a multi-meter. Step 1. Position main power switch to “OFF” Step 2. Disconnect (unplug) water heater from 120 volt power source. Step 3. Un-latch & remove surround cover from top of heater. Step 4. Carefully cut a path in the insulation from the blower tube towards the flame sensor (shown below). Pay close attention to not cut any wires.
Spark Rod Replacement Procedure WARNING 120 volt potential exposure. Isolate the appliance and reconfirm power is disconnected using a multi-meter. Step 1. Position main power switch to “OFF” Step 2. Disconnect (unplug) water heater from 120 volt power source. Step 3. Un-latch & remove surround cover from top of heater. Step 4. Carefully cut a path in the insulation from the blower tube towards the flame sensor (shown below). Pay close attention to not cut any wires.
Control Board Replacement Step 1. Position main power switch to “OFF” Step 2. Disconnect (unplug) water heater from 120 volt power source. Step 3. Un-latch and remove top surround cover from top of water heater. Step 4. Locate control board. Step 5. Remove 4 screws that attach display panel to control panel (save screws). Step 6. Carefully disconnect all wire connections from control board (Identify all wire connections) Step 7.
Transformer Replacement Procedure Step 1. Position main power switch to “OFF” Step 2. Disconnect (unplug) water heater from 120 volt power source. Step 3. Un-latch and remove top surround cover from top of water heater. Step 4. Disconnect primary leads (black & white) and secondary leads (blue & yellow) from the transformer. (leads are different sizes to prevent interchanging) Step 5.
Anode inspection and replacement WARNING Heater components and stored water may be HOT when performing the following steps in this procedure. Take necessary precaution to prevent personal injury. Step 1. Position main power switch to “OFF” Step 2. Disconnect (unplug) water heater from 120 volt power source. Step 3. Turn off water supply and drain water heater. Step 4. Locate (see photo below) and remove anode rods from heater (1-1/16 hex socket).
Step 1. When Error Code 29 is present you first must determine if the circulator or flow switch is bad. Step 2. Check if there is 120V to the circulator harness (see picture below). If voltage is not present trace wire harness for any sign of damage. Replace harness if damaged. If voltage is present replace circulator see step 5. Step 3. Check if the flow switch is working properly (see picture below). Using a volt meter check the continuity between top and bottom screw terminals on the flow switch.
Step 1. First determine is the “Blocked Vent Switch” was installed correctly on the drafthood (see picture right). Step 2. When Error Code 26 is present you first must determine if there is a blocked vent condition present. If so, clear the obstruction and reset the switch then continue with normal operation. Step 3. If the switch is tripped and there is no obstruction in the venting there could have been an extended down draft that tripped the switch.
Step 1. Un-latch and remove top surround cover from top of water heater. Step 2. Locate the damper at the back of the units. If the damper is working properly intake air should be pulling in through the screened elbow (see picture right). Step 3. Verify that the damper is in the “Open” position when there is a call for heat (see picture below). If you hear the blower on but damper is not open turn the power switch off for 30 seconds and recheck to see if damper opens.
Date Service Provider Model Number Phone Number Serial Number Venting: Vent 6", 7" or 8" Horizontal length Vertical length Gas Line: Gas Pressure: Venturi: Size & material Static Setting from Bottom in Turns Distance from meter to water heater Running Inlet Manifold Electrical: Line Voltage Low Voltage Spark Rod Resistance: Flame Sense Micro -Amps: Polarity Flame Sense Resistance:___________ Error Codes on Control Display (Direct Spark Ignition): __________________________________ Combus
U Model – Water Heater 1 Surround Assembly Combustion Assembly 2 (Specify model) 3 Ignition Control Assembly 4 Draft Hood (Specify model) 5 Vent Vertical Tube 6 Vent Protector Assembly 7 Baffle 3” Flue (Specify Model) 8 Damper Bracket (Specify Model) 9 Thermostat Sensor 10 Utility Cover 11 Circulator Assembly 12 ¾” NPT Nipple 13 Stainless Flex Connector 14 NPT/SAE Adapter 15 T&P (Specify Model) 16 Hot Water Outlet Plastisert Nipple 17 Anode 18 Cold Water Inlet (Hydrojet) Assembly 19 Plastic Hole Closure 20
Combustion Assembly 1 2 3 4 5 6 7 8 9 10 11 12 13 Combustion Assembly (Specify model) Blower/Gas Valve Assembly (Specify model) Burner Assembly (Specify model) Blower – (Specify model) Damper Assembly (Specify Model) Transition Tube Gasket Blower Transition Gasket Transition Tube 1/4 – 20 Nut Screw 8-32 x ¼” RHCR Gasket Flame Sense Gasket Igniter Sensor – Flame Sense 14 Igniter – Direct Spark Ignition 15 16 17 18 19 20 Blower / Burner Mounting Plate Gasket Burner (Specify Model) Burner (Specify Model) Bu
Ignition Control Assembly and Harnesses 1 2 3 4 5 6 7 8 9 10 Control Panel Control Transformer Display Panel Screw Switch Main Power Control Display Screw Blower/Circ/Damper Harness (24V) Damper Harness (120V) 11 12 13 14 15 16 17 18 Controller Harness (24V) Power Cord Harness (120V) Blocked Vent Switch Harness (24V) T-Stat Harness (24V) Control Display Harness (24V) Blower Harness (120V) Circ/Flow Harness (120V) BVS/Damper/Flow Harness (24V) 19 Ignition Harness (Direct Spark Ignition) 20 Flame Sense
AC BTU/H CO CO2 DC DSI ECO GFI GPM HSI Hz LED NOx NPT PSI RPM VA VAC W.C.
NOTES 54 54
NOTES 55 55
