Honeywell PDX50S60F-B-S-C-N-X, PDX450SF-BN-SX, PDX65S65F-B-S-C-N-X, PDX275TF-BN-SX-CX, PDX150SF-BN-SX-CX User Manual

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Manual 238-49770-00A

SERVICE

MANUAL

Troubleshooting Guide

and Instructions for Service

(To be performed ONLY by

qualified service providers)

Models Covered

by This Manual:

PDX Series Models:
PDX140S*F(BN,SX,CX)
PDX150S*F(BN,SX,CX)
PDX440S*F(BN,SX)
PDX450S*F(BN,SX)
PDX250T*F(BN,SX,CX)
PDX265T*F(BN,SX,CX)
PDX275T*F(BN,SX,CX)

PDX50S60F(B,S,C)*(N,X)
PDX65S65F(B,S,C)*(N,X)
PDX75S70F(B,S,C)*(N,X)
(*) Denotes Warranty Years

Powered Direct Vent Gas Water Heaters

PDX Series

Table of Contents

Page PDX Service Procedure

Introduction 4 - - -

How to use this manual 5 - - -

Tool required for service 5 - - -

Specifications 6 - - -

Control Timings 9 - - -

Sequence of Operation 10 - - -

Troubleshooting 13 - - -

Burner Inspection, Cleaning and Replacement 15 I

Pilot Testing, Cleaning and Replacement 17 II

Pressure Switch Testing and Replacement 18 III

Blower Testing and Replacement 20 IV

Blower Temperature Switch Testing and Replacement 22 V

Gas Control & Thermal well Testing & Replacement 24 VI

Flammable Vapor Sensor Testing & Replacement 28 VII

Safety Circuit Voltage Trace 29 VIII

115VAC Circuit Trace 30 IX

Dip Tube inspection and Replacement 31 X

Anode Inspection and Replacement 32 XI

Flue Baffle Inspection and Replacement 33 XII

Inner Door Removal, Inspection & Replacement 34 XIII

Glossary of Terms 38 - - -

Parts List 39 - - -

Page 2

2

PDX Series

WARNING: If the information in these instructions is

not followed exactly, a fire or explosion may result

causing property damage, personal injury, or death.

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.

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.

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, VENT­AIR INTAKE SYSTEM OR IN ANY LOCATION FROM WHICH

FUMES COULD REACH THE WATER HEATER OR VENT-AIR

INTAKE SYSTEM.

CAUTION

If sweat fittings are to be used DO NOTapply 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

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.

Incorrect operation of this appliance may

CAUTION

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

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.

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.

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

3

PDX Series

The new Bradford White PDX1, PDX2 and PDX4 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.

Introduction

Increased Vent Lengths - increased venting performance is achieved while maintaining

Energy Factor & FHSR performance.

The PDX1, PDX2, and PDX4 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 non metallic 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.

Page 4

4

How to Use This Manual

PDX Series

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 PDX 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.

Tools Required for Service

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.

Page 5

5

PDX Series

Power supply Dedicated 115VAC, 60 Hz, 15A

Gas Supply Pipe Minimum 1/2" NPT (schedule 40 black iron pipe recommended)

Approved Gas Type Natural or Propane. Unit must match gas type supplied.

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.)

Venting System Power direct vent through the wall or vertical through the roof

Approved Vent Materials PVC, CPVC or ABS

Minimum Clearance
for Servicing

Water Supply Pressure 150 PSI maximum allowable working pressure. Check local codes for supply pressure

Thermal well TCO Limit Residential 188°F (87°C), Commercial 199°F (93°C)

Residential Temperature
Set Point Range

Commercial Temperature
Set Point Range

18" from top, 24" from front, 4" sides and rear.

60°F (16°C) to 160°F (71°C) (Approximate temperatures)

80°F (27°C) to 180°F (82°C) (Approximate temperatures)

Specifications

Blower Temperature Switch Normally closed, opens @ 155°F (68°C), auto reset @ 128°F (54°C).

Standard Altitude-Normally open, closes at differential pressure of -.80.

Pressure switch

High Altitude-Normally open, closes at differential pressure of -.73.

Blower 115VAC, 60Hz, 3.1 amps.

Page 6

6

PDX Series

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.

Vent Tables

3" Diameter (7.6 cm) PVC Vent Connector Lengths

Maximum 75 gal.Maximum 48, 65 gal.

Terminating

Through the Wall

Through the Wall 2 50 (15.2) 2 (.6)

Through the Wall 3 45 (13.7) 2 (.6)

Through the Wall 4 40 (12.2) 2 (.6)

Through the Roof 0 60 (18.3) 7 (2.1)

Through the Roof 1 55 (16.8) 7 (2.1)

Through the Roof 2 50 (15.2) 7 (2.1)

Through the Roof 3 45 (13.7) 7 (2.1)

# of

Elbows

Maximum

Length ft (m)

Length ft (m)

1 55 (16.8) 2 (.6)

Minimum

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)

4" Diameter (10.2 cm) PVC Vent Connector Lengths

Terminating

Through the Wall

# of

Elbows

Maximum

Length ft (m)

Minimum

Length ft (m)

1 95 (29.0) 10 (3.1)

Through the Wall 2 90 (27.4) 10 (3.1)

Through the Wall 3 85 (25.9) 10 (3.1)

Through the Wall 4 80 (24.4) 10 (3.1)

Through the Wall 5 75 (22.9) 12 (3.6)

Through the Roof 0 100 (30.5) 15 (4.6)

Through the Roof 1 95 (29.0) 15 (4.6)

Through the Roof 2 90 (27.4) 15 (4.6)

Through the Roof 3 85 (25.9) 15 (4.6)

Through the Roof 4 80 (24.4) 15 (4.6)

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)

65 (19.8) 12 (3.6)

90 (27.4) 15 (4.6)

85 (25.9) 15 (4.6)

80 (24.4) 15 (4.6)

75 (22.9) 15 (4.6)

70 (21.3) 15 (4.6)

Page 7

7

PDX Series

Part II-Venting Specifications for:

40 Gallon
50 Gallon

Specifications

Vent Tables

The minimum equivalent length for the exhaust portion of the vent is 7 feet. The maximum equivalent vent length for the exhaust is 35 feet
for 2" diameter pipe and 85 feet for 3" diameter pipe. The intake portion of the vent must be equal to or less than the vent length of the
exhaust. The tables below are provided for your quick reference, some installations may require a greater number of elbows. When
calculating equivalent vent length, one 90° elbow is equivalent to 5 feet.

IMPORTANT

VENT CONNECTOR LENGTHS FOR 2" (5.1 cm) DIAMETER VENT PIPE

# of

Terminating

Through the Wall

Elbows

(excl. vent

term.)

1 30 (9.1)

Through the Wall 2 25 (7.6)

Through the Wall 3

Through the Wall 4 15 (4.6)

Through the Roof 0 35 (9.1)

Through the Roof 1 30 (9.1)

Through the Roof 2 25 (7.6)

Through the Roof 3 20 (6.1)

Maximum

straight

Length ft (m)

20 (6.1)

Minimum

straight

Length ft (m)

2 (.6)

2 (.6)

2 (.6)

2 (.6)

7 (2.1)

7 (2.1)

7 (2.1)

7 (2.1)

VENT CONNECTOR LENGTHS FOR 3" (7.6 cm) DIAMETER VENT PIPE

Terminating

Through the Wall

# of

Elbows

(excl. vent

term.)

1 80 (24.4)

Maximum

straight

Length ft (m)

Through the Wall 2 75 (22.9)

Through the Wall 3

70 (21.3)

Through the Wall 4 65 (19.8)

Through the Roof 5 60 (18.3)

Through the Roof 0 85 (29.9)

Through the Roof 1 80 (24.4)

Through the Roof 2 75 (22.9)

Through the Roof

Through the Roof

3 70 (22.3)

65 (19.8)4

Maximum

straight

Length ft (m)

10 (3.1)

10 (3.1)

10 (3.1)

10 (3.1)

10 (3.1)

15 (4.6)

15 (4.6)

15 (4.6)

15 (4.6)

15 (4.6)

Page 8

8

PDX Series

Control Timings

Pre-purge 15 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)

Verify Resistive Delay Retry after 2 Minutes (repeats 5 times)

Simulated Resistive Load Lockout Indefinite (cycle power to restart)

Hardware Error Lockout Indefinite (self clears if fault clears for at least 15 seconds)

Specifications

Ignition State Timing

Page 9

9

PDX Series

1

Start Up.

Upon power up, the control runs a safe-start check with a typical start-up delay of 1-5 seconds.

2

Flammable 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.

1

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.
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.

Sequence of Operation

2

Blower energizes.

3

Blower pre-purge period (15 seconds)

4

Differential 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.

5

Trial 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.

6

Main 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.

10

Page 10

PDX Series

Steady state operation.

7

8

Thermostat satisfies.

9

Burner off.

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 run 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.

Sequence of Operation

10

Blower post purge (15 seconds).

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.

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 11

11

Sequence of Operation

PDX Series

3. Pressure Switch/Blower Temperature Fault:

a) Pressure switch closed at start of call for heat - The control waits four seconds then, proceeds to flash

2 times with 3 second pause. The control waits 2 minutes and then turns on blower for 30 seconds. The blower
turns off after 30 seconds and the control waits for pressure switch to open. Any time the Pressure switch opens,
the blower turns on (or stays on) and the control proceeds to waiting for pressure switch to close.

b) Pressure switch or blower temperature switch failed open - The control runs the blower for 30 seconds

waiting for the pressure switch and/or blower temperature switch to close. If either switch does not close in 30
seconds, the blower turns off and the control flashes 3 times with 3 second pause. The control waits two
minutes before turning on the blower for another 30 seconds to see the circuit close. This cycle repeats as long as
there is a call for heat or until the circuit closes.

c) Pressure switch or blower temperature switch opens during burner operation - The control turns off the

pilot and main valve, runs blower for 15 seconds (inter-purge) waiting for pressure switch and/or blower
temperature switch to close. If either switch fails to close, the control proceeds as described in 3b above. If the
circuit closes again by the end of the inter-purge, the recycle counter is incremented, if the recycle count has

gins. If the recycle count has been reached, the control

not reached its limit (4), another trial for ignition

turns off the blower and flashes 6 times then 2 times with 3 second pause. The control waits 5 minutes before
repeating ignition sequence.

be

4. Trial For Ignition Fault:

a) Pressure switch opens during trial - The control turns off igniter and pilot valve. The gas control proceeds

as described in 3b above. If the pressure switch closes within 30 seconds the gas control will continue with trial for
ignition starting at blower pre-purge.

b) Flame Not Sensed - The control energizes the spark igniter attempting to light the pilot and prove flame. If

flame is not sensed within 90 seconds, the igniter turns off, the pilot valve is closed and the gas control runs the
blower through post purge and flashes 6 times then once with 3 second pause. The control waits 5 minutes before

repeating the ignition sequence.

5. Flame Sensing Fault:

a) Flame lost during run - The control turns off pilot and main valves, runs blower for 15 seconds (inter purge).

The control increments the recycle count, if the recycle count has not reached its limit (4), another trial for
ignition begins. If the recycle count has been reached, the control turns off the blower and flashes 6 times
then 3 times with 3 second pause. The control waits 5 minutes before repeating the ignition sequence.

b) Flame sensed out of sequence - the control only looks for pilot flame when the blower is running. If flame is

present when the pilot valve is not open, the control proceeds to wait for flame loss and flashes 5 times with 3
second pause. This continues until flame is lost, once the flame signal is lost, the control flashes 6 times then 4
times with 3 second pause. The control waits 5 minutes before repeating the ignition sequence.

12

Page 12