Bradford White PDX250T6*FBN User manual

Bradford White
PDX Series
Powered Direct Vent Gas Water Heaters
Save this manual for future reference
Manual 46925A
(*) Denotes Warranty Years
SERVICE
MANUAL
Troubleshooting Guide
and Instructions for Service
(To be performed ONLY by qualified service providers)
For Bradford White
PDX Series Models:
PDX250T6*F(BN,CX)
PDX265T6*F(BN,CX)
PDX275T6*F(BN,CX)
PDX50S60F(B,C)*(N,X)
PDX65S65F(B,C)*(N,X)
PDX75S70F(B,C)*(N,X)

Bradford White
PDX Series
Powered Direct Vent Gas Water Heaters
Table of Contents
Page TTW Service Procedure
Introduction 4 - - -
How to use this manual 5 - - -
Tool required for service 5 - - -
Specifications 6 - - -
Control Timings 8 - - -
Sequence of Operation 9 - - -
Troubleshooting 12 - - -
Burner Inspection, Cleaning and Replacement 14 I
Pilot Testing, Cleaning and Replacement 16 II
Pressure Switch Testing and Replacement 17 III
Blower Testing and Replacement 21 IV
Blower Temperature Switch Testing and Replacement 23 V
Gas Control & Thermal well Testing & Replacement 25 VI
Flammable Vapor Sensor Testing & Replacement 29 VII
Safety Circuit Voltage Trace 30 VIII
115VAC Circuit Trace 31 IX
Dip Tube inspection and Replacement 32 X
Anode Inspection and Replacement 33 XI
Flue Baffle Inspection and Replacement 34 XII
Inner Door Removal, Inspection & Replacement 35 XIII
Glossary of Terms 38 - - -
Parts List 39 - - -
Page 2
2

WARNING: If the information in these
instructions is not followed exactly, a fire or
explosion may result causing property damage,
personal injury, or death.
WHAT TO DO IF YOU SMELL GAS
Do not try to light any appliance.
Do not touch any electrical switch; do not use any
phone in your building.
Immediately call your gas supplier from a neighbor's
phone. Follow the gas supplier's instructions.
If you cannot reach your gas supplier, call the fire
department.
Installation and service must be performed by a qualified
installer, service agency or the gas supplier.
FOR YOUR SAFETY
Do not store or use gasoline or other
flammable, combustible, or corrosive vapors
and liquids in the vicinity of this or any other
appliance.
CAUTION
Incorrect operation of this
appliance may create a hazard to
life and property and will nullify the
warranty.
DANGER
Do not store or use gasoline or
other flammable, combustible, or
corrosive vapors and liquids in the
vicinity of this or any other
appliance.
IMPORTANT
Before proceeding, please inspect the
water heater and its components for
possible damage. DO NOT install any
water heater with damaged
components. If damage is evident
then please contact the supplier where
the water heater was purchased or the
manufacturer listed on the rating plate
for replacement parts.
WARNING
Water heaters are heat producing appliances. To
avoid damage or injury, do not store materials
against the water heater or vent-air intake system.
Use proper care to avoid unnecessary contact
(especially by children) with the water heater and
vent-air intake components. UNDER NO
CIRCUMSTANCES MUST FLAMMABLE
MATERIALS, SUCH AS GASOLINE OR PAINT
THINNER BE USED OR STORED IN THE VICINITY
OF THIS WATER HEATER, VENT-AIR INTAKE
SYSTEM OR IN ANY LOCATION FROM WHICH
FUMES COULD REACH THE WATER HEATER
OR VENT-AIR INTAKE SYSTEM.
WARNING
DO NOT ATTEMPT TO LIGHT ANY GAS APPLIANCE
IF YOU ARE NOT CERTAIN OF THE FOLLOWING:
Liquefied petroleum gases/propane gas and
natural gas have an odorant added by the gas
supplier that aids in the detection of the gas.
Most people recognize this odor as a “sulfur” or
“rotten egg” smell.
Other conditions, such as “odorant fade” can
cause the odorant to diminish in intensity, or
”fade”, and not be as readily detectable.
If you have a diminished sense of smell, or are in
any way unsure of the presence of gas,
immediately contact your gas supplier from a
neighbor's telephone.
Gas detectors are available. Contact your gas
supplier, or plumbing professional, for more
information.
CAUTION
If sweat fittings are to be used DO NOT apply heat to
the nipples on top of the water heater. Sweat the
tubing to the adapter before fitting the adapter to the
water connections. It is imperative that heat is not
applied to the nipples containing a plastic liner. WARNING
FAILURE TO INSTALL AND MAINTAIN A NEW,
LISTED 3/4” X 3/4” TEMPERATURE AND PRESSURE
RELIEF VALVE WILL RELEASE THE
MANUFACTURER FROM ANY CLAIM THAT MIGHT
RESULT FROM EXCESSIVE TEMPERATURE AND
PRESSURES.
WARNING
Hydrogen gas can be produced in an operating
water heater that has not had water drawn from the
tank for a long period of time (generally two weeks or
more). Hydrogen gas is extremely flammable. To
prevent the possibility of injury under these
conditions, we recommend the hot water faucet to be
open for several minutes at the kitchen sink before
you use any electrical appliance which is connected
to the hot water system. If hydrogen is present,
there will be an unusual sound such as air escaping
through the pipes as hot water begins to flow. Do
not smoke or have open flame near the faucet at the
time it is open.
CAUTION
Turn off or disconnect the electrical power supply to the
water heater before servicing. Label all wires prior to
disconnection when servicing controls. Wiring errors
can cause improper and dangerous operation. Verify
proper operation after servicing.
Page 3
PDX Series
3

Page 4
Introduction
The new Bradford White PDX2 and PDX water heaters are designed to provide reliable
performance with enhanced standard features. New design features include reliable spark to
pilot ignition system, enhanced diagnostics, simplified servicing, significantly quieter
operation, additional vent lengths and certified FVIR technology.
Spark to Pilot Ignition System - employing the spark to pilot ignition system promotes
reliable and consistent pilot and main burner ignitions to provide hot water on demand.
Integrated Immersion Thermostat/Gas Control Valve with LED - was developed for ease
of troubleshooting by providing simple diagnostic codes to pinpoint an installation or
component performance issue.
New Powerful Blower - will eliminate problems with difficult venting situations.
Quieter and Cooler Blower Operation - blower noise is significantly reduced for both
interior and exterior environments. Cooler operation increases blower life by reducing bearing
wear and noise.
Rugged Wiring Connections - receptacle type connections promote error free wiring.
Increased Vent Lengths - increased venting performance is achieved while maintaining
Energy Factor & FHSR performance.
The PDX2 and PDX water heaters use a combustion system were flue gases are combined with
dilution air to reduce the flue gas temperature in the blower, combustion air and dilution air are
drawn from outside the building. The diluted flue gases are evacuated to the exterior through
low temperature vent materials. The gas control maintains water temperature, ignition
sequence and regulates gas flow. A safety circuit consisting of a pressure switch and blower
temperature switch verifies proper conditions exist for safe and reliable operation. If a situation
outside of normal operating parameters exists, the gas control diagnostic LED will flash a code
to positively identify an operational issue.
This service manual is designed to facilitate problem diagnosis and enhance service efficiency.
To further promote quicker service times the new gas valve can be removed and replaced
without draining the water heater. A special tool is required and will be provided with each gas
valve kit shipped from our Service Parts department.
Please read the service manual completely before attempting service on this new series of
power vent models.
How the Safety System Works
During normal operation, air for combustion is drawn into the water heater though the vent pipe from outside your
building. The air travels into the closed combustion chamber. The air then mixes with in a normal manner with
supplied gas and its efficiently combusted, producing very low NOx emissions.
In the unlikely event trace amounts of flammable vapors are present in the area surrounding the water heater, the
sealed combustion system prevents the flammable vapors from reaching the ignition source. In addition the
flammable vapors sensor will stop the water heater from operating if a significant amount of flammable vapors are
present.
PDX Series
4

Tools Required for Service
It is intended for this manual to be used by qualified service personal for the primary purpose of
troubleshooting and repair of the Bradford White TTW Series water heaters. Understanding the
sequence of operation section of this manual will contribute greatly to troubleshooting the water
heater.
The Honeywell WV4460E Electronic Gas Control will display error codes in the event of abnormal
operation. Error codes are listed in the troubleshooting chart beginning on page 12 of this service
manual. The troubleshooting chart will also indicate the probable cause for the error code and
direct the service professional to a service procedure to properly diagnose the abnormal operation.
In some difficult to diagnose conditions, it may be necessary to isolate the heater from the vent
system to determine the problem.
Contact the Bradford White technical support group immediately if diagnosis can not be made
using the methods described in this service manual.
Page 5
Manometer: A liquid “U” tube type or a digital (magna-helic) type can be used. This
device is used to measure gas and/or air pressure and vacuum.
Multi-Meter: A digital type is strongly recommended. This device is used to measure
electrical values. The meter you select must have the capability to
measure volts AC, volts DC, Amps, micro-amps and ohms.
Electronic Probes: In some cases, standard multi-meter probes will damage or simply
not be effective to obtain certain voltage and ohm reading. It will be
necessary to have special electronic “pin” type multi-meter probes.
These probes are available at most electronic wholesale outlets.
Thermometer: Used to measure water temperature. An accurate thermometer is
recommended.
Water Pressure Gage: Used to measure water supply pressure. Also used to determine tank
pressure by adapting to the drain valve of the heater.
Gas Control Service Tool: BWC part number 239-45991-00. A specialized tool designed to remove
the gas control from gas control thermal well. Available from
your Bradford White parts supplier.
Various Hand Tools: Pipe wrench, channel locks, open end wrenchs (3/8",7/16",½"),
12" crescent wrench, Allen wrench set, screw drivers (common &
Phillips), ¼" nut driver, pliers (common & needle nose), socket set, side
cutters wire cutters, wire strippers, wire crimpers, torpedo level, small
shop vac, step ladder, and flashlight, 5 gallon pail.
How to Use This Manual
PDX Series
5

Specifications
Thermal well TCO Limit Residential 188°F (87°C), Commercial 199°F (93°C)
Residential Temperature
Set Point Range 60°F (16°C) to 160°F (71°C) (Approximate temperatures)
Blower Temperature
Switch Normally closed, opens @ 165°F (74°C), auto reset @ 130°F (54°C).
Blower 115VAC, 60Hz, 3.1 amps.
Pressure switch
Exhaust-Normally open, closes on vacuum increase @ -1.30.
Intake-Normally closed, opens on vacuum increase @ -1.15.
Power supply Dedicated 115VAC, 60 Hz, 15A
Approved Gas Type Natural or Propane. Unit must match gas type supplied.
Venting System Power vent through the wall or vertical through the roof
Approved Vent Materials PVC, CPVC or ABS
Gas Supply Pipe Minimum 1/2" NPT (schedule 40 black iron pipe recommended)
Minimum Clearance
for Servicing 18" from top, 24" from front, 4" sides and rear.
Water Supply Pressure 150 PSI maximum allowable working pressure. Check local codes for supply pressure
Gas Pressure 5.0" W.C. min. for Nat gas, 11.0" W.C. min. for L.P. gas, 14.0" W.C. maximum (Nat. & L.P.)
Commercial Temperature
Set Point Range 80°F (27°C) to 180°F (82°C) (Approximate temperatures)
Page 6
PDX Series
6

Specifications
Venting Specifications for:
48 Gallon
65 Gallon
75 Gallon
This water heater is approved for installation with the following PVC, CPVC or ABS
Schedule 40 venting material.
The maximum and minimum vent lengths listed on this label are for the exhaust portion of
the vent. The intake portion of the vent must be equal to or less than the length of the
exhaust.
Through the Wall
Terminating # of
Elbows Maximum
Length ft (m)
Minimum
Length ft (m)
3" Diameter (7.6 cm) PVC Vent Connector Lengths
155 (16.8) 2 (.6)
Through the Wall 250 (15.2) 2 (.6)
Through the Wall 345 (13.7) 2 (.6)
Through the Wall 440 (12.2) 2 (.6)
Through the Wall
Terminating # of
Elbows Maximum
Length ft (m)
Minimum
Length ft (m)
4" Diameter (10.2 cm) PVC Vent Connector Lengths
195 (29.0) 10 (3.1)
Through the Wall 290 (27.4) 10 (3.1)
Through the Wall 385 (25.9) 10 (3.1)
Through the Wall 480 (24.4) 10 (3.1)
Through the Roof 060 (18.3) 7 (2.1)
Through the Roof 155 (16.8) 7 (2.1)
Through the Roof 250 (15.2) 7 (2.1)
Through the Roof 345 (13.7) 7 (2.1)
Through the Roof 0100 (30.5) 15 (4.6)
Through the Roof 195 (29.0) 15 (4.6)
Through the Roof 290 (27.4) 15 (4.6)
Through the Roof 385 (25.9) 15 (4.6)
Through the Wall 575 (22.9) 12 (3.6)
Through the Roof 480 (24.4) 15 (4.6)
Vent Tables
Page 7
PDX Series
Maximum
Length ft (m)
Minimum
Length ft (m)
45 (13.7) 2 (.6)
40 (12.2) 2 (.6)
35 (10.7) 2 (.6)
30 (9.1) 2 (.6)
50 (15.2) 7 (2.1)
45 (13.7) 7 (2.1)
40 (12.2) 7 (2.1)
35 (10.7) 7 (2.1)
Maximum 75 gal.Maximum 48, 65 gal.
Maximum 75 gal.Maximum 48, 65 gal.
Maximum
Length ft (m)
Minimum
Length ft (m)
85 (25.9) 10 (3.1)
80 (24.4) 10 (3.1)
75 (22.9) 10 (3.1)
70 (21.3) 10 (3.1)
90 (27.4) 15 (4.6)
85 (25.9) 15 (4.6)
80 (24.4) 15 (4.6)
75 (22.9) 15 (4.6)
65 (19.8) 12 (3.6)
70 (21.3) 15 (4.6)
7

Control Timings
Ignition State Timing
Pre-purge 2 Seconds
Trial for Ignition 90 Seconds
Flame Stabilization Period 3 Seconds
Inter-purge 15 Seconds
Flame Failure Response Time 1.5 Seconds (2 second. Maximum; 1 second minimum.)
Post-purge 15 Seconds
PS Fault Delay (failed open/close) Retry after 2 Minutes
Soft Lockout Retry after 5 Minutes
TCO Limit Lockout Indefinite (cycle power to restart)
Simulated Resistive Load Lockout Indefinite (cycle power to restart)
Hardware Error Lockout Indefinite (self clears if fault clears for at least 15 seconds)
Verify Resistive Delay Retry after 2 Minutes (repeats 5 times)
Specifications
Page 8
Wiring Diagram
PDX Series
8

Sequence of Operation
Thermostat calls for heat.
Prior to energizing blower, gas control checks safety circuit to insure the circuit is open. Normal switch positions
in the safety circuit are as follows:
a) Exhaust pressure switch normally open.
b) Blower temperature switch normally closed.
c) Inlet pressure switch normally closed.
If the safety circuit is closed, the control waits 4 seconds, gas control LED flashes 2 times with 3 second pause.
Gas control waits 2 minutes then, blower runs for 30 seconds. This cycle repeats until safety circuit opens.
Power up Sequence
1Start Up.
Upon power up, the control runs a safe-start check with a typical start-up delay of 1-5 seconds.
2Flammable Vapor Check.
To assure no outputs are energized if the “Flammable Vapor Sensor” is out of range, the control will test the
the “Flammable Vapor Sensor” for proper operating range. If the “Flammable Vapor Sensor” is within range the
control resumes normal operation with no perceptible delay. If the “Flammable Vapor Sensor” is out of range, the
control LED immediately flashes 7 times with 3 second pause.
Normal Heating Sequence
1
2Blower energizes.
3
Exhaust pressure switch proves blower/vent system operation.
a) If the pressure switch does not close within 30 seconds, the control LED Flashes 3 times with 3 second pause.
The blower runs for 30 seconds every 2 minutes trying to get the pressure switch or blower temperature switch
to close. This cycle repeats as long as there is a call for heat.
b) The normally closed inlet pressure switch allows the system to work as long as the inlet air is not blocked.
4
Blower pre-purge period (2 seconds)
5Trial for pilot ignition (90 seconds).
a) The gas control lights the pilot by activating spark igniter and gas flow to pilot burner.
b) If flame is not sensed within 90 seconds, igniter and gas flow are deactivated, blower will post purge and
control LED flashes 6 times with 3 second pause.
6Main burner Ignition
After pilot flame is sensed, gas control activates main valve for main burner ignition. The gas control will ignore
flame and pressure switch signals for 3 seconds allowing for main burner to stabilize.
Page 9
PDX Series
9

Steady state operation.
During Steady State Operation the Control Monitors:
Thermostat temperature sensor- When set point temperature is satisfied, gas valve is shut down and
blower will post purge for 15 seconds. Control LED flashes a short flash once every 4 seconds (idle) status
code.
Pressure switch / Blower temperature switch- If either switch opens, pilot valve and main valve is shut
down. The blower continues to runs for 30 seconds attempting to close the circuit. The control LED Flashes
3 times with 3 second pause.
Flame Sense- If flame is lost, pilot & main valve are shut down, blower runs for 15 seconds. Control attempts
to re-light pilot 4 times. If unsuccessful, Blower is shut down and control proceeds to 5 minute lockout. Control
re-attempts to light pilot starting at normal heating sequence #2.
Thermostat satisfies.
Burner off.
Blower post purge (15 seconds).
9
8
10
7
Sequence of Operation
Abnormal Operation
1. Simulated Resistive Device Fault:
a) If the Flammable Vapor Sensor resistance is greater than 70,000 Ohms - the gas control immediately turns
off all outputs. Control waits and monitors resistance for 30 seconds. If the resistance is greater than 70,000 ohms
after 30 seconds, the gas control proceeds to verify resistive delay for 2 minutes and flashes 7 times with a three
second pause. This process is repeated 5 times until the control either returns to normal operation or proceeds
to a lockout mode flashing 7 times with a 3 second pause.
b) If the Flammable Vapor Sensor resistance is below 3000 ohms - The gas control immediately turns off all
outputs and proceeds to flash 8 times then once with three second pause. The error self clears if the resistance
returns to normal range for at least 15 seconds.
Normal Heating Sequence (cont.)
2. Temperature Sensor Fault:
a) Temperature sensor detected open circuit - The gas control Immediately turns off all outputs and proceeds to
flash 8 times then three times with three second pause. The error self clears if the fault clears for at least 15
seconds.
b) Temperature sensors not reading the same temperature within ±5.5 °F - The gas control Immediately turns off
all outputs and proceeds to flash 8 times then three times with three second pause. The error self clears if the fault
clears for at least 15 seconds.
c) Water temperature in excess of TCO (Temperature Cut Off) limit - The gas control immediately turns off pilot &
main valve and proceeds to flash 4 times with 3 second pause. Blower continues to run until gas control is reset.
Power needs to be cycled to remove gas control from TCO lockout.
Page 10
PDX Series
10