SERVICE MANUAL - SPARK PLUG IGNITION MODELS

LOW PRESSURE PORTABLE FORCED AIR HEATER SPARK PLUG IGNITION MODELS

Table Of Contents

Heaters
- 1 -
Return to Table Of Contents

SAFETY INFORMATION

Danger WARNINGS

IMPORTANT: Read this owner's manual carefully and completely before trying to assemble, operate, or service this heater. Improper use of this heater can cause serious injury or death from burns, fire, explosion, electrical shock, and carbon monoxide poisoning.

Danger DANGER: Carbon monoxide poisoning may lead to death!

Carbon Monoxide Poisoning: Early signs of carbon monoxide poisoning resemble the flu, with headaches, dizziness, and/or nausea. If you have these signs, the heater may not be working properly. Get fresh air at once! Have heater serviced. Some people are more affected by carbon monoxide than others. These include pregnant women, persons with heart or lung disease or anemia, those under the influence of alcohol, and those at high altitudes.

Make certain you read and understand all warnings. Keep this manual for reference. It is your guide to safe and proper operation of this heater.

- 2 -
Return to Table Of Contents

TABLE OF CONTENTS

General Information

  1. Arrangement of Manual
  2. Technical Service Department
  3. Service Preparation
  4. Tools Required
  5. Parts

Specifications

  1. General Specifications
    1. Fuel Selection
    2. Electrical
    3. Ventilation
    4. Heater Sizing
    5. Heater Performance Specifications

Component Operation

  1. I. Air System
    1. Air Pump
    2. Air Filters
    3. Nozzle
  2. Electrical System
    1. Motors
    2. Solid State Relay
    3. Safety Control / Photocell
    4. Electronic ignitor
  3. Fuel System
  4. Combustion System
  5. All Systems Working Together

Troubleshooting

  1. Safety Requirements
  2. Cautions
  3. Using the Ohmmeter
    1. Setting Up the Ohmmeter
    2. Calibration
  4. Diagnostic Charts

Diagrams and Charts

  1. Wiring Diagrams
  2. Motor Resistance Chart

GENERAL INFORMATION

I. ARRANGEMENT OF MANUAL

This manual contains information and service procedures to assist the service technician in understanding and correcting problems on DESA International oil-fired portable forced air heaters. The first section of the manual contains basic information concerning the operation of the different components in the heater. This information should be reviewed by service personnel to provide a basic understanding of how the components function in the working system. Section four of this manual is intended to provide a quick reference concerning conditions which result in customer complaints. These procedures will help the service technician quickly diagnose a malfunctioning heater. The illustrations in this manual may not necessarily depict the actual heater model, and are intended for reference ONLY.

II. TECHNICAL SERVICE DEPARTMENT

The Technical Service Department, located in Martin, Michigan, is committed to assisting our Authorized Service Centers to increase their service knowledge, so that they can provide prompt, efficient service. This Service Manual covers the majority of problems that are associated with the heaters. However, as with any product, certain problems can arise which have not been covered. If such problems arise, please call the Technical Service Department's number, 1-800-475-5660, to address these technical problem areas. If you need assistance for ordering parts, billing questions, etc. you should contact 1-800-475-5660.

III. SERVICE PREPARATION

A clean work area at the start of each job is essential for efficient service work. Heaters which are extremely dirty should be cleaned prior to service. Cleaning will occasionally uncover the problem area. Tools needed for the job should be obtained before work is started. Delays resulting from locating tools result in lost time and wages.

Clean fuel should always be used when testing heaters. Many problems are often traced to the use of the wrong type of fuel or dirty fuel.

Use caution and common sense when working on a heater. Always remember that kerosene is flammable, electrical parts can result in the potential shock and the heater parts are hot during operation, which could result in burns if one is not careful.

- 3 -
Return to Table Of Contents

IV. TOOLS REQUIRED

In addition to common hand tools, the service shop should have the following tools and instruments for proper repairing of the heaters. These instruments will be referred to throughout this manual.

INSTRUMENT RANGE PART NUMBER
Pressure Gauge 0-15 PSI HA1180
Feeler Gauge .001 to .1 inch None*
Volt Ohmmeter RX1/AC 250V None**

*Available at any auto parts store.
**Available at most electronic stores.

Tools Required

V. PARTS

Accessories

In addition to the standard parts we now offer parts kits. Listed below are the item numbers and the accessory description

ITEM NUMBER ACCESSORY
HA1176A Parts Kit/All Models
HA1180 Air Gauge/All Models
HA1210 Thermostat/Forced Air & LP Forced Air
HA1202 Heavy Duty Wheel Kit
Fits: 30, 35, 40, 50, 55, 70 Models
HA1206 Wheel Kit
Fits: 30, 35, 40, 50, 55, 70 Models
HA2203 Rear Handle Fits: 100, 110 Models
HA2204 Rear Handle
Fits: 150, 155, 165, 200 Models
HA2210 Filler Neck Screen
HA3003 Flame Out Safety Control
HA3004 Rotor Kit 1/2"
HA3006 Nozzle (35, 40 Models)
HA3007 Nozzle (50 Models)
HA3008 Nozzle (70 Models)
HA3009 Nozzle (100, 110 Models)
HA3011 Nozzle (150, 155 Models)
HA3012 Spark Plug
(70, 100, 150, 155, 165, 200 Models)
HA3013 Spark Plug (35, 50 Models)
HA3014 Air Filter Kit (30, 50, 70 Models)
HA3017 Filter Kit
(100, 110, 150, 155, 165, 200 Models)
HA3025 Tune Up Center Display
HA3005 Rotor Kit 5/8"
HA3021 Nozzle (55 Models)
HA3023 Nozzle (165 Models)
HA3019 Photocell
HA3020 Pump Adjustment Kit
- 4 -
Return to Table Of Contents

Tune Up Center

The Tune Up Center (HA3025) shown below includes the parts listed.

Part No. Includes Qty. Description
HA1210 2 Thermostat
HA3003 (098205-04) 3 Flame Out Safety Control
HA3004 (M22456-1, M22009, M8643) 3 Rotor Kit
HA3005 (M22456-2, M22009, M8643-2) Rotor Kit 5/8"
HA3006 (100735-02) 2 Nozzle
HA3007 (100735-03) 2 Nozzle
HA3008 (100735-04, M8882) 2 Nozzle Kit
HA3009 (100735-06, M8882) 2 Nozzle Kit
HA3011 (100735-07, M8882) 2 Nozzle Kit
HA3012 (M10962-2) 4 Spark Plug
HA3013 (M29835) 3 Spark Plug
HA3014 (M29632, M29612-01, M29633) 3 Air Filter Kit
HA3017 (M12179, M11637, M12244-1, M51150-01) 3 Filter Kit
HA3019 (M16656-16) Photo Cell
HA3020 (M10993-1, M22997, M27694, M8940) Pump Adjustment Kit

Tune Up Center

SPECIFICATIONS

I. GENERAL SPECIFICATIONS

1. Fuel Selection

One of the most critical specifications for trouble-free operation is the use of a clean, acceptable fuel. Listed below are guidelines and comments concerning operation of heaters with different fuels.

RECOMMENDED FUELS COMMENTS
Kerosene
Fuel Oil No.1
Jet "A"
Best overall results. Minimum odor and minimum maintenance. No additives necessary for cold weather operation.
ALTERNATE FUELS COMMENTS
Fuel Oil No. 2
Diesel No. 1
Diesel No. 2
Noticeable increase in odor. Requires frequent maintenance of fuel filter, nozzle and spark plug. Requires a winterizing additive at temperatures below 20°F

2. Electrical

The heater must be connected to a standard electrical outlet (120V/60HZ). For safety, all heaters are equipped with a three prong power cord, which must be grounded. When selecting an extension cord for heater usage, the following chart should be used in determining wire size.

LENGTH OF CORD WIRE SIZE (AWG)
100 Ft. No. 14
200 Ft. No. 12
300 Ft. No. 10
400 Ft. No. 8
No. 6

3. Ventilation

The heater should be used only in well-ventilated areas. As a rule, the following minimum requirements should be followed.

HEATER SIZE (BTU) SQUARE FOOT OPENING
30,000 / 35,000 1.0 Sq. Ft.
50,000 / 55,000 1.6 Sq. Ft.
70,000 2.1 Sq. Ft.
100,000 / 110,000 3.2 Sq. Ft.
150,000 / 155,000 4.5 Sq. Ft.
165,000 5.0 Sq. Ft.
200,000 6.0 Sq. Ft.

The above is based on ventilation requirements of at least a 3 sq. ft. opening per 100,000 BTU. If possible, it is better to provide cross-ventilation to achieve better air movement.

- 5 -
Return to Table Of Contents

4. Heater Sizing

The user should be aware of the proper size heater needed for a particular application. It is easy to see that a 30,000 BTU heater would not heat a large warehouse, but the question is sometimes asked "What size heater should I use?" A simple formula that can be used to determine heater BTU requirements follows:

Cu. Ft. of Area X .133 X Desired Temp. Rise °F = BTU Size Needed.

Example:
Area: 50' multiplied by 25' multiplied by 10' = 12,500 Cu. Ft.
Desired Temp. Rise: 30°F

12,500 (Cu. Ft.) multiplied by .133 (Factor) = 1662.5
1662.5 multiplied by 30 (Temp. Rise) 49,875 (Proper Heater Size)

ANSWER: A 50,000 BTU heater should be selected for this application.

II. HEATER PERFORMANCE SPECIFICATIONS (SPARK PLUG MODELS)

Reddy Heater Brand Technical Service Heater Performance Data

Heater Model BTU Rating Pump P.S.I. ± 1 Nozzle Part No. Nozzle Flow GPH ± 5% Motor Part No. Motor R.P.M. Motor Horsepower Motor Start Relay or Solid State Relay Fuel Tank Capacity (Gal) Hot Air Output (C.F.M) AMPS (running) Spark Plug Gap (inches)
R30 30,000 3.0 M29681 0.23 102001-01 1725 1/15 Not Used 3.0 165 2.8 .050/.060
R35, R35A, R35B 35,000 3.0 100735-02 0.27 102001-01 1725 1/15 Not Used 3.0 165 2.8 .050/.060
R50, R50A, R50B 50,000 3.6 M50597 0.37 102001-01 1725 1/15 Not Used 4.0 165 2.9 .050/.060
R55 55,000 3.4 100735-17 0.40 102001-01 3450 1/15 Not Used 5.0 175 2.9 .050/.060
R70, R70A, R70B, R70BT 70,000 4.0 100235-04 0.52 097308-02 3415 1/8 M25061-1 5.0 250 3.0 .050/.060
R100, R100A 100,000 4.0 100735-06 0.74 097300-02 3450 1/5 097061-01 9.0 480 5.5 .070/.080
R110 110,000 4.0 100735-06 0.80 097300-02 3450 1/5 097061-01 9.0 490 5.5 .070/.080
R150B, R150D 150,000 3.4 100735-07 1.10 097300-02 3450 1/5 099061-01 13.5 550 5.0 .070/.080
R165 165,000 5.4 100735-10 1.10 102001-07 3450 1/4 097061-01 13.5 575 5.0 .070/.080
R200 200,000 6.0 100735-13 1.4 102001-07 3450 1/4 097061-01 13.5 600 4.5 .105/.115

A 102482-01 Transformer or Electronic ignotor will apply to all models for service.

- 6 -
Return to Table Of Contents

COMPONENT OPERATION

I. AIR SYSTEM

1. Air Pump

The heater's air pump consists of a rotor with four carbon blades rotating inside a pump body. The rotor is driven directly by the motor and is attached to the motor shaft by means of a plastic insert. As the motor rotates, the carbon blades travel outward rubbing against the inside surface of the steel pump body. The rotor's position inside the pump body is such that it is not concentric with the pump body and a .003/.004 of an inch gap is set at the uppermost quadrant. As the motor rotates, the air between the blades is compressed and routed to the nozzle through the air line.

Air Pump
Direction of Rotation - Clockwise

2. Air Filters

The air filtering system consists of an air input filter and an air output filter. The air input filter is located at the right rear of the motor and its purpose is to filter all incoming air prior to entering the air pump. The filter design is such that it can be cleaned in a mild, soapy solution, thoroughly dried and used over again. The air output filter is located under the plastic end cover. This filter's purpose is to prevent any carbon dust (from rotor or blade wear) from entering the air passages in the nozzle. This filter is non-cleanable and should be replaced when considerable buildup of carbon dust is observed. (See drawings below).

BTU Filter 70
30,000, 35,000, 50,000, 55,000, and 70,000 BTU Filter System
BTU Filter 200
100,000, 110,000, 150,000, 155,000, 165,000, and 200,000 BTU Filter System

3. Nozzle

As mentioned previously, the purpose of the air pump is to compress air and deliver it to the nozzle. The compressed air, as it travels through the nozzle, creates a negative pressure that extends back through the center of the nozzle. This negative pressure lifts the fuel from the fuel tank. The fuel from the fuel tank and the compressed air are mixed at the nozzle which results in a very fine mist of fuel being sprayed into the combustion chamber. The air pump/nozzle combination eliminates the need for a conventional type fuel pump. It is important for the service technician to understand the nozzle operation. In many cases concerning improper operation of a heater, the problem is the result of a seal leak or a restriction (dust/dirt) being present within the nozzle. It should also be pointed out that each model heater requires different nozzles due to different fuel flow rates.

Nozzle

I. ELECTRICAL SYSTEM

1. Motors

The motors used on the low pressure heaters are fractional horsepower motors ranging from 1/15 HP on the smallest heater to 1/4 HP on the largest heaters. The motors used can be grouped into two categories. The first category is the shaded pole motor. The shaded pole motor contains a single winding and does not require an external start relay for operation.

These motors are easily identified by observing that only two wires (usually red and white) are necessary for operation.

The second category is the split-phase motor. This motor contains two separate windings. The first winding being the auxiliary or start winding and the second being the main or run winding. This motor requires and external means of switching the power off to the auxiliary winding after the motor reaches a predetermined speed. This power off switching is accomplished by a motor start relay or solid state relay. These motors are identified by observing that three wires (black, red and white) are routed from the motor.

Shared Pole Motor
Shaded Pole Motor
Split Phase Motor
Split-Phase Motor
- 7 -
Return to Table Of Contents

2. Solid State Relay

Applicable models use 097061-01 Solid State Relay.

The solid state relay is used to de-energize the start winding on split-phase motors. As mentioned in the Motor Section, remember that split-phase motors have both an auxiliary (start) and a main (run) winding. For proper motor operation, both the auxiliary and main winding are energized during start up. After the motor starts and reaches approximately 80% of rated speed, the auxiliary winding must be de-energized to prevent overheating. This is accomplished by the use of a solid state relay. The operation of the relay functions as a positive temperature coefficient resistor. When voltage is applied to the motor, the main and auxiliary windings are energized as current flows through the solid state relay which is connected in series with the auxiliary winding only. The resistance is increased over time in the solid state relay where it eventually rises to the point that theoretically no current flows, de-energizing the auxiliary winding.

Solid State Relay
Solid State Relay

3. Safety Control / Photocell

The safety control circuit consists of a photocell (light sensitive cell) and a safety control. The photocell is used to sense the presence of light inside the combustion chamber. The photocell varies its electrical resistance in relation to the light rays which contact its surface. When the heater is operating properly, the photocell sees sufficient and proper color light, which keeps its resistance low. When the photocell does not sense the proper color or amount of light, the resistance of the photocell increases and forces an electrical current to flow through the solid state trigger circuit. The current flows into the circuit breaker and heats a metal bar causing the bar to warp (bimetal). The warpage releases the spring loaded reset button, which breaks all power to the heater. As a service technician, it is important to understand the operation of the safety control. In the past, it has been the single most misdiagnosed part of the heater. It is suggested that all controls be checked per instructions listed in the Troubleshooting Section, prior to replacement.

Flameout Safety Controls
Enclosed Flameout
Enclosed Design
Photocell Flameout
Photocell
- 8 -
Return to Table Of Contents

4. Electronic Ignitor

All models use 102482-01 Electronic Ignitor Kit.

The electronic ignitor operates on 120V/60Hz. It delivers approximately 6,000 volts average to the spark plug causing the kerosene sprayed from the nozzle assembly to ignite. The ignitor operates on a pulse basis. The ignitor has no internal service parts and must be replaced when found defective.

Note: It is important for the service technician to be cautious when working with the electronic ignitor due to its high voltage output.

Electronic Ignitor

III. FUEL SYSTEM (Fuel filters)

There are several types of fuel filters used on different model heaters. The filters are always located in line with the fuel pickup tube. The purpose of the filter is to eliminate the possibility of dirt, dust, etc. from entering the nozzle and restricting the flow. The filters should be inspected and cleaned whenever a heater is brought in for service. It is also important that the bottom of the tank be inspected for sedimentation or dirt buildup. The filter's design is such that a possible restriction in the filter screen can be present during operation and be dislodged back into the tank when the heater is shut off.

Fuel Filters

IV. COMBUSTION SYSTEM (Burner Head)

The burner head is mounted to the rear of the combustion chamber. The purpose of the burner head is to meter and mix the amount of air entering the chamber to obtain proper combustion characteristics. The nozzle is mounted in the center of the burner head and is surrounded by fins,so that the amount of air entering the chamber from the burner head is equal and balanced. The size of the slots in the burner head differ between models.

Burner Head

V. ALL SYSTEMS WORKING TOGETHER

There are four basic systems within the heater: the fuel system, the air system, the electrical system and the combustion system.

An air pump (A) on one end of the motor shaft forces air through the air line (G) and out the burner nozzle (I). The moving air creates a pressure differential in the burner head (N) causing fuel to be drawn from the tank (J). The fuel-air mixture is sprayed into the combustion chamber (L) in a fine mist.

Addition air is supplied to the combustion chamber by a fan (O) to enter the combustion chamber where it mixes with the air and fuel from the nozzle. The remaining air is directed around and over the combustion chamber. This air mixes with the heated air from the combustion chamber and is ejected as a jet of clean, heated air (K).

The ignition system consists of an electronic ignitor (E) and spark plug (M). The electronic ignitor increases the input voltage to a very high potential, which causes and arc to jump between the electrodes of the spark plug. The arc is used to ignite the fuel and air mixture within the combustion chamber. The arc fires constantly during operation.

In the safety circuit, the flame sensor detects the presence of light from the flame inside the combustion chamber.

All Systems Working Together
- 9 -
Return to Table Of Contents

TROUBLESHOOTING

I. SAFETY REQUIREMENTS

This service manual is intended for use by individuals with an adequate knowledge of electrical and mechanical skills. Attempts to repair this heater by individuals without those skills can result in personal injury, as well as property damage.

II. CAUTIONS

  1. Before servicing, disconnect the heater from the electrical power source by removing the electrical plug from the wall receptacle.
  2. Do not bypass safety devices.
  3. If replacement parts are necessary, do not substitute with non-factory parts (use only factory authorized replacement parts).
  4. Make sure all electrical connections are secure and all harness leads are in place prior to connection to electrical power source.

III. USING THE OHMMETER

Continuity Check: Throughout the diagnostic procedures, you will be required to check continuity of the electrical circuits. A brief description of how to set up the ohmmeter for these tests follows.

1. Setting Up the Ohmmeter
  1. Use a small screwdriver to adjust the plastic screw on the zero "0" mark to the far left of the scale.
  2. With the battery installed, set the switch to the "RX1" position.
  3. Plug in test wires and use insulated alligator clips.
Ohmmeter
Typical Ohmmeter
2. Calibration
  1. A. Zero meter - connect the alligator clips to each other. The meter pointer should move to far right of ohms scale (see Figure B).
  2. B. Use the OHM thumb adjustment knob to set the pointer at the "0" mark on the scale. If pointer will not zero, replace battery.

Note: If you are using a digital readout ohmmeter, calibrate according to manufacturer's instructions.

Ohmmeter

IV. DIAGNOSTIC CHARTS

The following pages contain various diagnostic charts. To use the charts, find the "Observed Fault" that exists and follow test procedure.

Observed Fault Index

Motor starts - Unit does not ignite . . . . . . . . . . . . . . . . . . . . 11

Motor does not run or runs at slow
speeds. Spark is observed at plug . . . . . . . . . . . . . . . . . . . 14

Heater does not start / motor and
transformer does not operate . . . . . . . . . . . . . . . . . . . . . . . 17

Heater ignites and burns; However,
Safety control trips and heater shuts off . . . . . . . . . . . . . . . 19

Frequent plug fouling/delayed ignition . . . . . . . . . . . . . . . . . 22

- 10 -
Return to Table Of Contents

OBSERVED FAULT

Motor Starts - Unit Does Not Ignight

TEST PROCEDURE

1Check Spark Plug for Proper Gap

See Heater Performance Specifications "Spark Plug Gap", page 6, for proper gap. Reset gap with feeler gauge.

2Defective Transformer or Electronic Ignitor

Connect the transformer or electronic ignitor to a properly gapped spark plug. Establish a good ground between the spark plug and heater. Plug in the heater cord and observe for spark between electrodes. If the ground is good and a spark does not jump the gap, the transformer or ignitor is defective.

CAUTION: DO NOT LET ANY PORTION OF YOUR BODY TOUCH ELECTRODES OR PLUG, DUE TO HIGH VOLTAGE.

3Cracked Spark Plug

During the above test, if spark is observed at any portion of the plug, except at the electrodes, the porcelain insulator is cracked and the plug must be replaced.

Spark Gap
Check Spark
- 11 -
Return to Table Of Contents

4Check for Proper Pump Pressure

Install HA1180 Pressure Gauge or equivalent to rear of air filter housing. Start heater and adjust air pressure to specified pressure. Turning adjustment screw clockwise increases pressure, counterclockwise decreases pressure. The screwdriver must be removed from the slot after any adjustment before taking a reading on the gauge (see Heater Performance Specifications on page 6 for specified pressures).

Note: Pressure gauge must be scaled in 1/4 pound increments for accurate measurement.

5 Check for Restricted Fuel Flow

Remove the burner head from heater. Using a socket wrench, carefully remove the nozzle from burner head. (Be extremely careful not to scratch or score the face of the nozzle).

A. Seal Leak

Remove the rubber seal washer from stem of nozzle and discard. (To be safe, always replace nozzle sleeve during servicing of burner head). Even the smallest air leak in this area can reduce flow rates and result in problems.

Note: On smaller heaters (30,000, 35,000, 50,000, and 55,000 BTU), inspect "O" ring, do not remove.

Install a new rubber seal to stem of nozzle. Make sure the seal washer, spring and second seal washer are in place before reinstalling nozzle in the burner head.

Gauge Adjust
Burner Nozzle
Nozzle Seal
- 12 -
Return to Table Of Contents
B. Filter Blocked

On certain models, a drop-in fuel filter is located in the copper or aluminum line that attaches to the fuel fitting on the back side of the burner head. Lift the filter out of the copper or aluminum fuel line and clean, if necessary.

C. Restriction in Nozzle or Burner Head

Using a compressed air source, blow the compressed air through the outlet end of nozzle to dislodge any possible restriction.

CAUTION: NEVER DRILL OUT OR TRY TO INCREASE NOZZLE SIZE.

Using compressed air, also blow through passages in burner head. The air should be directed form input fitting at rear of head to the center of burner head. Many times the restriction to the flow is due to metal chips, etc. being present in the burner head assembly.

Blow Out Nozzle
Blow Out Burner

6 Fuel Filter Restriction

The fuel filter should be inspected and cleaned. The filters are located in the fuel line either at tank location, in the copper or aluminum tubing or in line with the fuel line at access cover.

Filter Restricting
- 13 -
Return to Table Of Contents

OBSERVED FAULT

Motor Does Not Run or Runs at Slow Speeds. Spark is Observed at Plug.

TEST PROCEDURE

1 Broken Rotor or Blades

Disassemble the end cover filter and end pump cover from rear of motor. Visually inspect the rotor and blades for breakage. Make sure that the rotor and blades are free of any type of lubricant. Rotor and blades must be clean and dry for proper operation.

2 Improper Rotor Clearance

Check rotor with feeler gauge for proper clearance between rotor and pump body. Rotate rotor and make sure all four quadrants of rotor have adequate clearance.

Rotor Blades
Rotor Clearance
- 14 -
Return to Table Of Contents

3 Oversized Rotor

If the fan is hard to turn when the motor end cover is installed, but easy to turn when loosened, the rotor should be removed and lightly sanded. Remove the rotor and lightly sand by placing rotor in the palm of hand and sanding on a flat surface making figure eight rotations. (Use the finest grade of sandpaper available).

4 Dry Motor Bearing

If the fan is difficult to turn with air pump parts removed, apply 8 to 12 drops of a non-detergent oil to the sleeve bearing on the fan of the motor. The bearing located at the pump end is of the ball bearing type and should not be lubricated. DO NOT OIL PUMP END BEARING.

Note: Motor manufactured after 1978 have permanently lubricated sleeve bearing and cannot be oiled

5 Open Motor Windings

Motors Without Relay (30,000, 35,000, 50,000, and 55,000 BTU)

With the heater disconnected from AC plug, connect the ohmmeter on the RX1 scale to the wires coming from motor. On smaller heaters, the leads from the motor should indicate a resistance of 6 to 8 ohms. Actual resistance varies between motor types.

Note: Resistance's may vary due to motor temperature.

Motors with Relays (70,000, 100,000, 110,000, 150,000, 165,000, and 200,000 BTU)

Start Winding
Connect the ohmmeter on the RX1 scale to the white and black wires coming from motor. This procedure allows you to determine the condition of the start winding. If the meter indicates infinity (open circuit) or the meter goes full scale (zero ohms), the winding is defective and the motor must be replaced. Actual resistance varies between motor types.

Main Winding
Connect the ohmmeter on the RX1 scale to the red and white wires coming from motor. If the needle does not move again or goes to full scale, the motor must be replaced. Actual resistance varies between motor types.

Sanding Rotor
Oil Fan Bearing
Test Motor with No Relay
Start Winding Test
Main Winding Test
- 15 -
Return to Table Of Contents

6 Defective Solid State Relay

Prepare a jumper wire approximately 8" long with a male quick disconnect terminal at one end and a test probe at the other end. Disconnect the black wire coming from the motor that is connected to the solid state relay terminal. Connect this black wire to the male connection of jumper wire. Touch the test probe to the opposite terminal of the solid state relay and plug in the heater. As soon as the motor reaches speed, remove the test probe from terminal. The motor should continue to run. If the motor operates correctly, the solid state relay should be replaced.

CAUTION: DO NOT TOUCH ELECTRICAL CONNECTIONS OR ALLOW THEM TO TOUCH METAL PARTS OF THE HEATER.

7 Low Voltage to Heater

In certain circumstance, a heater may operate correctly when being tested in the service shop, but the customer complains that it does not start at times on the job site. It is important that the customer is made aware that if the heater is operated on an incorrectly sized extension cord or a low voltage outlet, the heater's motor will not start due to low voltage. If the customer has the availability of a voltmeter, have the customer check the voltage at the heater. A minimum of 108 volts, while the heater is running, is necessary for proper operation. Refer to the Electrical Section of this manual (page 5) for proper extension cord sizing.

Defective Solid State Relay
Low Voltage
- 16 -
Return to Table Of Contents

OBSERVED FAULT

Heater Does Not Start - Motor and Transformer / Ignitor Does Not Operate.

TEST PROCEDURE

1 Check That Reset Button on Safety Control is Fully Depressed

Visually inspect the black reset button on safety control. The button must be fully depressed and latched in for operation.

2 Check Wiring Connections at Safety Control and Wire Nuts for Proper Fit.

Wire Nuts
Physically check electrical connections at wire nuts and safety control for proper fit. Check for continuity between male prongs of power cord to safety control.

Terminal Board
Make sure connections are secure.

Reset Button
Wire Connections
- 17 -
Return to Table Of Contents

3 Check for Continuity of Circuit Breaker

Standard Safety Control (098205-04)
With the heater disconnected from AC source, disconnect the red and black wires connected to the safety control. Push reset button in. With the ohmmeter on the 0 to 200 OHM scale, check for continuity across terminals where wires were removed. Meter should indicate "0".

Breaker Continuity
Breaker Continuity
- 18 -
Return to Table Of Contents

OBSERVED FAULT

Heater Ignites and Burns; However, Safety Control Trips and Heater Shuts Off.

TEST PROCEDURE

1 Defective Safety Control (098205-04)

Make sure unit is disconnected from AC source. Disconnect the blue wire coming from safety control that is connected to blue wire at photocell (connection is made in smaller wire nut connection).

Connect the blue wire from control under the wire nut connection where the white wires are connected. Plug unit into AC supply. If the reset button on the safety control pops out and unit shuts off, the control is defective and must be replaced.

Safety Bypass Check
- 19 -
Return to Table Of Contents

2 Defective Photocell

Inspect the lens of the photocell for soot/dirt, etc... If dirty, wipe off with a clean, damp cloth.

Remove photocell from heater and connect ohmmeter on the 1000 Ohm (RX1K) scale. Hold the lens up to a light source (60 watt light bulb, direct sunlight, etc.) with the lens of the photocell pointed toward the light source. The resistance of the meter should be low (less than 500 ohms).

By blocking off the light source by putting thumb over opening of photocell, the resistance on meter should be high. Replace the photocell if a change in resistance is not observed during the above test.

Clean Photocell
Test Photocell

3 Loose Wire Nut or Terminal Board Connection

Physically check that all electrical connections are secure and making electrical contact.

4 Dirty Photocell

See step #2, column 1.

5 Check for Proper Pump Pressure

Install HA1180 Pressure Gauge or equivalent to rear of air filter housing. Start heater and adjust air pressure to specified pressure. Turning adjustment screw clockwise increases pressure, counterclockwise decreases pressure. The screwdriver must be removed from the slot after any adjustment before taking a reading on the gauge. (See Heater Performance Specifications on page 6 for specified pressures).

Note: Pressure gauge must be scaled in 1/4 pound increments for accurate measurement.

6 Check for Restricted Fuel Flow

Remove the burner head from heater. Using a socket wrench, carefully remove the nozzle from burner head. (Be extremely careful not to scratch or score the face of the nozzle).

Gauge Adjust
Burner Nozzle
- 20 -
Return to Table Of Contents

Restricted Fuel Flow continued

A. Seal Leak
Remove the rubber seal washer from stem of nozzle and discard. (To be safe, always replace nozzle sleeve during servicing of burner head). Even the smallest air leak in this area can reduce flow rates and result in problems. Note: On smaller heaters (30,000 thru 55,000 BTU), inspect “O” ring, do not remove. Install a new rubber seal to stem of nozzle. Make sure the seal washer, spring and second seal washer are in place before reinstalling nozzle in the burner head.

B. Fuel Filter Clogged
Clean or replace fuel filter as necessary.; filter is located at lower end of fuel pickup tube on 30 thru 70 and 200 models. Filter is located on top of fuel tank on 100 thru 165 models. On 200 model the filter is located at the end of fuel line inside fuel tank.

C. Restriction in Nozzle or Burner Head
Using a compressed air source, blow the compressed air through the outlet end of nozzle to dislodge any possible restriction.

CAUTION: NEVER DRILL OUT OR TRY TO INCREASE NOZZLE SIZE.

Using compressed air, also blow through passages in burner head. The air should be directed from input fitting at rear of head to the center of burner head. Many times the restriction to the flow is due to metal chips, etc. being present in the burner head assembly.

Nozzle Seal
Blow Nozzle
Blow Burner
Fuel Filter Restrict
- 21 -
Return to Table Of Contents

7 Fuel Cap and Gasket Not Vented

Inspect the vent hole and gasket under the fuel cap to make sure the passage is open. Remember that since the fuel is being drawn from the tank, the tank must be vented for proper operation.

8 Fuel Cap Has More Than One Gasket

Make sure cap has only one gasket installed.

Fuel Cap Gasket

OBSERVED FAULT

Frequent Plug Fouling - Delayed Ignition.

TEST PROCEDURE

1 Spark Plug Too Close to Spray Pattern of Nozzle

It may be necessary in some cases to move the spark plug back from spray pattern of nozzle. The best method is to shim the plug back by placing a standard spark plug washer under the flat of the plug at threaded area. This moves the plug back approximately .1 inch and reduces the possibility of the plug fouling with carbon or the plug becoming wet during the ignition cycle.

2 Wrong Fuel

Refer to Fuel Selection on page 5 of this manual.

Spark Plug Shim
- 22 -
Return to Table Of Contents

DIAGRAMS AND CHARTS

I. WIRING DIAGRAMS

55 BTU Wiring Diagram
30,000, 35,000, 50,000, & 55,000 BTU Heaters
200 BTU Wiring Diagram
70,000 - 200,000 BTU Heaters - Heaters Equipped With Solid State Relay

II. MOTOR RESISTANCE CHART

MOTOR RED TO WHITE
MAIN (± 7%) OHMS
BLACK TO WHITE
AUXILIARY (± 7%) OHMS
100088-01 6.2 --
097130-02 7.5 16.5
097134-02 3.5 18.3
101898-01 2.8 9.1
Allparts Equipment and Accessories
M & S Service Co. Inc.
P.O. Box 158
Plainwell, Michigan 49080

079337-01 02/10

Return to Table Of Contents