background image

H I G H   P R E S S U R E   P O R T A B L E   F O R C E D   A I R   H E A T E R   S E R V I C E   M A N U A L

14

TROUBLESHOOTING — PROBLEM CONDITIONS

OBSERVED PROBLEM
Spark plug sparks, but motor does not start.

POSSIBLE CAUSE

A. Motor protector tripped
B. Fuel pump seized
C. Defective motor
D. Defective relay (if equipped)
E. Defective fan switch

TEST PROCEDURES
A. Motor protector tripped

Depress red motor protector reset button on
top of motor case. This resets the motor
protector for proper operation. Determine
causes for motor protector trips before re-
turning heater to customer.

B. Fuel pump seized

1. Unplug heater.
2. Remove upper shell of heater.

3. Rotate fan by hand to determine if pump

is free to turn.

4. If fan is difficult or impossible to rotate,

loosen clamp which holds fuel pump to
motor. Rotate fan and retighten clamp.

5. If fan is still difficult or impossible to

rotate, replace fuel pump.

C. Defective motor

1. Depress red motor protector reset but-

ton on top of motor case before testing
motor.

2. Unplug heater.
3. Disconnect the red and white motor wires

at their wire connection.

4. Set ohmmeter on the RX1 position.
5. Connect ohmmeter test leads to red and

white motor wire. If the resistance indi-
cated reads 0 ohms or indicates an open
circuit, the motor is defective and must be
replaced. 

Note:  Proper resistance for

motor is 1.0 to 1.5 ohms. Make sure you
properly calibrate ohmmeter before test-
ing motor.

D. Defective relay (if equipped)

Replace defective relay.

E. Defective fan switch
Follow steps under DEFECTIVE FAN
SWITCH, procedure “D” on page 20.

Figure 17 - Rotating Fan by Hand

Reset Button

Figure 16 - Reset Button Location

Figure 18 - Testing Motor with Ohmmeter

Summary of Contents for B350D

Page 1: ...al Service Department P O Box 90004 2701 Industrial Drive Bowling Green Kentucky 42102 9004 SERVICE MANUAL HIGH PRESSURE PORTABLE FORCED AIR HEA TERS 600 SIDE PFA PV 009 350 SIDE PFA PV 008 INTERNATIONAL DESA ...

Page 2: ...m 8 Fuel Pump 8 Fuel Filters 9 Nozzle 9 Electrical System 10 Motor 10 Flame Control Assembly 10 Ignition Transformer 11 Fuel Solenoid Valve 11 Fan Switch 11 Section 5 Troubleshooting Safety Requirements 12 Using an Ohmmeter 12 Setting Up the Ohmmeter 12 Calibrating the Ohmmeter 12 Diagnostic Information 12 Problem Conditions Frequent Spark Plug Fouling Delayed Ignition 13 Spark Plug Sparks but Mot...

Page 3: ... are present Follow all local ordinances and codes when using heater Use only in well vented areas Provide at least three 3 square feet of fresh outside air for each 100 000 BTU Hr of rating This heater produces carbon monoxide which is listed by the State of California as a reproductive toxin under Proposition 65 Use only in places free of flammable vapors or high dust content Use only with the e...

Page 4: ...ease call the TechnicalServiceDepartmentat1 800 323 5190 The Technical Service Department is open from 8 00 am to 4 00 pm Central Time This number is only for servicing problems and cannot be used for ordering parts billing questions etc Service Preparation A clean work area at the start of each job is essential for efficient service work Clean extremely dirty heaters before servicing Cleaning wil...

Page 5: ...size extension cord for heater Length of Cord Wire Size AWG 100 ft No 14 200 ft No 12 300 ft No 10 400 ft No 8 500 ft No 6 3 S E C T I O N Ventilation Only use heater in well ventilated areas The following chart shows the minimum fresh outside air opening needed for proper venti lation Heater Size Square Foot BTU Hr Opening 250 000 7 5 300 000 9 0 350 000 10 5 600 000 18 0 The above chart is based...

Page 6: ...V 60Hz 120V 60Hz Amperage Normal Run 7 1 11 5 Motor RPM 1725 1725 Fuel Pump Pressure PSI 100 110 Spark Plug Gap 050 060 050 060 Weight Approx Lbs Dry 180 285 With Full Fuel Tank 390 550 Wiring Diagrams Wiring Diagram for Non Terminal Block Heater with Standard Flame Control 1 2 3 RELAY A B 7 5 FLAME CONTROL WHITE ORANGE RED GREEN MOTOR PHOTO CELL BLUE BLACK SPARK PLUG BLACK BLACK BLACK BLACK BLACK...

Page 7: ...WHITE THERMOSTAT WHITE WHITE BLUE PHOTO CELL WHITE GREEN BLACK BLACK WHITE ORANGE ORANGE RED RED RED YELLOW YELLOW SOLENOID VALVE WHITE MOTOR T R A N S F O R M E R 3 2 1 WHITE WHITE BLACK WHITE WHITE 1 3 2 FAN SWITCH 7 5 B A MOTOR RELAY WHITE RED ORANGE ORANGE RED BLACK WHITE BLACK WHITE BLUE BLUE WHITE BLACK BLACK THERMOSTAT B R FLAME CONTROL RESET BUTTON RED YELLOW YELLOW RED WHITE SOLENOID VALV...

Page 8: ... fuel pump draws fuel into one of the ports marked INLETS After fuel pump draws fuel into INLET port the fuel is then pressurized in the pump The fuel pump then forces fuel to the burner head nozzle thru the port marked NOZZLE The port marked PRESS ADJ contains an adjustment screw Turning this screw will increase or decrease the fuel pump pres sure Check fuel pump pressure by attaching high pressu...

Page 9: ...ter out very small particles which may be present in the fuel system This high degree of filtering is needed to prevent any sediment or foreign material from reaching the nozzle Make sure to clean orreplacethisfilterelementevery250hoursof operation Clean or replace this filter more often if fuel quality is bad Nozzle The nozzle could be classified as the heart of the fuel system The nozzle works s...

Page 10: ...e motor will run again press red reset button located on top of the motor housing see Figure 5 Figure 6 White Rogers Robert Shaw Flame Control Figure 7 Standard Flame Control R E S E T ELECTRICAL SYSTEM Motor The motor is a fractional horsepower motor The motor drives the fuel pump and rotates the fan The turning fan delivers air into and around the combustion chamber The motor contains two separa...

Page 11: ...as an on off valve for fuel flow to the nozzle When the thermostat on the heater turns heater on the solenoid valve opens allow ing fuel to flow to the nozzle When the thermostat on the heater turns heater off the solenoid valve closes preventing fuel from reaching the nozzle Figure 9 Fuel Solenoid Valve Figure 8 Ignition Transformer Ignition Transformer The ignition transformer operates on 120V 6...

Page 12: ...tic screw in the center of the ohmmeter just under the meter needle Turning this screw will move the needle Turn the screw to ad just the meter needle to the zero 0 mark on the far left of the scale see Figure 11 2 Make sure batteries are in ohmmeter Set ohmmeter on the RX1 position 3 Plug test leads into ohmmeter If test leads do not have alligator clips install alligator clips to leads CAUTION O...

Page 13: ...BLE CAUSES A Poor fuel quality B Sparkplugtipistooclosetospraypattern of nozzle C Incorrect fuel pump pressure D Dirty or damaged nozzle TEST PROCEDURES A Poor fuel quality Usegoodqualityfuel SeeGENERALSPECI FICATIONS AND APPLICATIONS INFOR MATION page 5 for fuel guidelines B Spark plug tip is too close to spray pattern of nozzle 1 Remove upper shell of heater 2 Remove spark plug from burner head ...

Page 14: ...ossible to rotate loosen clamp which holds fuel pump to motor Rotate fan and retighten clamp 5 If fan is still difficult or impossible to rotate replace fuel pump C Defective motor 1 Depress red motor protector reset but ton on top of motor case before testing motor 2 Unplug heater 3 Disconnecttheredandwhitemotorwires at their wire connection 4 Set ohmmeter on the RX1 position 5 Connect ohmmeter t...

Page 15: ...perly grounded by the 2 mounting screws Look for loose fasteners corro sion broken tabs etc 5 Connect the transformer secondary lead to the spark plug 6 Establish a good ground between the spark plug body and heater To do this attach a grounding wire to heater shell Clip grounding wire to grounding outer electrode on spark plug see Figure 20 Use insulated pliers to hold spark plug at spark plug he...

Page 16: ...el solenoidvalve is working properly If nozzle is not spray ing out fuel unplug heater and follow stepsbelowtodetermineifsolenoidvalve is defective 3 Disconnect yellow and white wires from solenoid valve 4 Set ohmmeter on the 250VAC position 5 Connect ohmmeter test leads to yellow and white wires that were connected to solenoid valve 6 Connect heater to electrical supply If 120VAC is being sent to...

Page 17: ...ED NOZZLE procedure D on page 13 Figure 23 Removing Fuel Filter H Dirty fuel filter The fuel filter at fuel pump is housed in the fuel filter canister 1 Remove canister bottom from canister top 2 Remove fuel filter from canister bottom 3 Inspect canister bottom and fuel filter for water or accumulated dirt 4 Rinse canister bottom in clean kerosene 5 Wipe dry with a clean cloth 6 Iffuelfilterisdirt...

Page 18: ...haw flame control It is located beside the motor and covered by the wiring cover plate The reset button is located on the side of the motor support Follow the directions below that match the flame control on your heater White Rogers Robert Shaw Flame Control Part Number M50230 1 Unplug heater 2 Remove upper shell of heater 3 Disconnect the two photocell wires from the terminals marked F F on flame...

Page 19: ...irty wipe off with clean soft cloth 5 Replace photocell 6 Replace upper shell on heater 7 Connectheatertoelectricalsupply Ifprob lem remains continue with steps below 8 Unplug heater 9 Remove upper shell of heater 10 Removephotocellfromphotocellbracket attached to burner head 11 Check photocell with HA1170 tester or use the following procedure A Disconnect blue and white photocell wires from blue ...

Page 20: ...ing Terminals 1 and 3 of Fan Switch 6 Connect test leads from ohmmeter to terminals marked 1 and 2 on fan switch 7 Apply a low level of heat to the face of the switch Do this with a lit match heated soldering iron etc Ohmmeter should read continuity 0 ohms when fan switch is heated 8 Replace fan switch if any of these condi tions are not met during testing E Incorrect fuel pump pressure Followstep...

Page 21: ...te It is either black or grey in color with the reset button located on top The standard flame control is much smaller than the White Rogers Robert Shaw flame control It is located beside the motor and covered by the wiring cover plate The reset button is located on the side of the motor support Depress reset button on flame control This will reset the flame control for proper opera tion D Defecti...

Page 22: ...existing nozzle with a 3 5 gph 70 degree type A hollow spray pattern nozzle DESA part number M14969 Figure 32 Burner Head and Head Orifice 4 Check pump pressure Make sure pump pressure is 110 psi Note Reinstall original nozzle and burner head orifice if heater was equipped with one if moving heater to lower altitudes 350 000 BTU Hr Model 1 Remove upper shell of heater 2 Remove burner head orifice ...

Page 23: ...ontact your nearest Parts Central or call DESA International s Parts Department at 502 781 9600 When calling DESA International have ready model number of your heater the replacement part number ACCESSORIES AND SERVICE INFORMATION ACCESSORIES Purchase heater accessories and parts from your local dealer If your dealer or service center cannot supply an accessory or part contact your nearest Parts C...

Page 24: ...H I G H P R E S S U R E P O R T A B L E F O R C E D A I R H E A T E R S E R V I C E M A N U A L 24 099352 01 Rev A 1 92 INTERNATIONAL DESA 2701 Industrial Drive P O Box 90004 Bowling Green KY 42102 9004 ...

Reviews: