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1-26.  Overheat Protector Switch (High Limit Switch) 
 

This switch is rated at 90°C (195°F). Should the heater overheat (internal temperature 
rises beyond 90°C (195°F)), the overheat protector switch (also called a high limit 
switch) will open to shut off the heater. The power lamp will simultaneously flash. The 
overheat protector switch will automatically reset after the heater has cooled down. 
 
Once the heater has cooled to 70°C (160°F), the system can be restarted manually as 
follows. 
 

1.  Push in the HEAT switch to “OFF” position. 
2.  Allow heater to cool down. 
3.  Resolve the cause of the overheat. 
4.  Push in the HEAT switch to 

ON

 position. 

 

The heater will continue operation again. 
 

Summary of Contents for Toyoset NS-2800

Page 1: ...SERVICE MANUAL CABIN HEATER MODEL NS 2800 TOYOTOMI CO LTD NAGOYA JAPAN ...

Page 2: ...otor Assembly 8 1 16 Heat Exchanger 8 1 17 Fuel Delivery System 8 1 18 Fuel Tank 9 1 19 Solenoid Fuel Pump 9 1 20 Electrical System 9 1 21 Control Circuit Board 9 1 22 Temperature Sensor 9 1 23 Safety Mechanism 9 1 24 Power Failure Recovery System 9 1 25 Fuse 9 1 26 Overheat Protector Switch High Limit Switch 10 Section 2 Installation 2 1 Introduction 11 2 2 Physical Placement of Heater 11 2 3 Pow...

Page 3: ...Inspection of Exhaust Air Lines 19 4 4 Verification of Igniter Operation 19 4 5 Fuel Contamination 20 Section 5 Component Specifications and Adjustments 5 1 Main Circuit Board 21 5 2 Igniter 21 5 3 Burner Thermistor 21 5 4 Fuel Pump 22 5 5 Burner Mat 22 5 6 High Limit Switch 23 5 7 Blower Motor 23 Section 6 Troubleshooting Guide 6 1 Troubleshooting Guide I 24 6 2 Troubleshooting Guide II 26 6 3 Tr...

Page 4: ...h Limit Switch 36 7 10 Main Circuit Board 37 7 11 Heat Exchanger 37 7 12 Heat Chamber and Flame Rod 38 7 13 Burner Ring 39 7 14 Burner Mat 39 7 15 Burner Assembly 39 7 16 Burner Thermistor 39 7 17 Blower Motor Assembly 40 Section 8 Circuit Board Specifications 8 1 Wiring Diagram 42 8 2 Time Chart 43 Section 9 Parts Description 9 1 Exploded View 44 9 2 Parts List 45 9 3 Accessories 46 ...

Page 5: ... 410 mm x 190 mm x 315 mm 16 1 8 x7 1 2 x12 3 8 Weight 9 0 kg 20 lbs Flue Pipe Outer nominal 50 mm 2 in Inner nominal 25 mm 1 in 1 3 Description of Functions Fuel is delivered by the solenoid fuel pump to the burner assembly through the fuel nozzle Simultaneously air is delivered by the blower fan to the burner assembly through small holes located on the inside burner wall At the starting the igni...

Page 6: ...g to the burner At the same time fuel is metered from a storage tank into this same burner Within the burner the air fuel mixture is ignited to produce heat The Laser combustion system is safeguarded by an overheat protector switch high limit switch that will shut down the heater to protect it from damage in the event of excessive heat build up The overheat protector switch will be reset after the...

Page 7: ... intake fan of the combustion blower to the base of the burner The flame sensor is mounted through the wall of the heat chamber 1 7 Burner The burner has double wall construction and contains an igniter tube a fuel inlet fitting and a series of air holes on the inner wall 1 8 Burner Ring This part is designed to promote efficient burning The burner ring is held by spring clips to mounting posts wi...

Page 8: ... circulation fans mounted on a common shaft One side is the intake air fan and the other is the circulation fan The intake fan draws in outside air through the flue pipe for internal combustion The cabin heater blower motor has a two stage speed fan The larger diameter intake fan keeps the air pressure within combustion system lower than the room air The operation modes control the fan speeds and ...

Page 9: ...ature sensor which is capable of sensing room temperature within a range of 0 to 30 C 32 to 85 F can be wall mounted Approximately 2 5 m 8 1 5 ft of wire is supplied with sensor to facilitate wall mounting in a favorable location 1 23 Safety Mechanism Several safety mechanisms have been built into the Laser Heating System These devices protect the user against personal injury protect the heater ag...

Page 10: ...n to shut off the heater The power lamp will simultaneously flash The overheat protector switch will automatically reset after the heater has cooled down Once the heater has cooled to 70 C 160 F the system can be restarted manually as follows 1 Push in the HEAT switch to OFF position 2 Allow heater to cool down 3 Resolve the cause of the overheat 4 Push in the HEAT switch to ON position The heater...

Page 11: ... and fire codes The requirement of these codes must be followed to insure lawful installation and use 2 2 Physical Placement of Heater In addition to the space taken up by the heater interior space must also be reserved for free air circulation Remove all combustibles from the heating area Unless building boat or fire codes dictate otherwise the cabin heater can be placed on any floor surface or w...

Page 12: ...cabinet and lift the heater from the shipping carton E Remove the plastic bag covering the heater F Remove the plastic bag containing the heater parts from the installation kit box and set it aside G Check for parts as listed in the Owner s Manual IMPORTANT Only the standard accessories and attachments are shipped with the heater The TOYOSET dealers distributors will also stock other accessories a...

Page 13: ...st as a guide to the fuel storage facilities 1 The fuel supply tube must be shorter than 1 5 m 5 ft 2 Piping should include no inverse U type bends to avoid air locks which could block the fuel supply 3 A fuel strainer must be used to avoid fuel pump failure 21 Fuel pipe Part 17185654 22 Insert cap nut Part 17185330 23 Sleeve Part 17185335 24 Strainer Part 17185336 ...

Page 14: ...in the U S and Canada Heat Rating High 2 300 kcal h 2 675 w h 9 800 BTU h Low 1 150 kcal h 1 335 w h 4 900 BTU H Fuel Consumption High 0 28 L h 0 07 gal h Low 0 14 L h 0 04 gal h Heating Efficiency Approx 90 Power Source DC 12V Power Consumption Ignition 96 W 3 minutes Burning High 27 W Low 17W Normal Operating Current High 2 3 A Low 1 4 A Current Fuse 10 Amp Safety Devices Ignition safety device ...

Page 15: ...motor operates for ventilation 3 Temperature Selector The room temperature can be set from 10 to 30 C 50 to 85 F 4 Monitor Lamps These lamps indicate conditions of operation and warnings Malfunction POWER YELLOW FLAME RED VENT GREEN High limit switch activated O Room temp sensor malfunction or disconnect O Ignition safety device activated Flame sensor activated O Igniter coil broken Power voltage ...

Page 16: ...ed If the flame is detected operation will continue and the flame lamp will remain lit If not the heater is extinguished and the flame lamp will flash The heater operates at LOW combustion for 5 minutes after the flame is detected regardless of temperature setting After this period the heater will run at three stages HIGH LOW and OFF cycle to maintain the desired temperature 3 5 Turning Heater Off...

Page 17: ...ter off STEP 1 Turn the heater off to cool down the heater STEP 2 Be sure that the heater is cool to the touch A period of 30 to 40 minutes should be sufficient to permit the heater to cool completely STEP 3 Check for the reason for overheating Overheating is usually caused by objects that impede free air circulation Look for debris and other obstructions near the heated air outlet and at the flue...

Page 18: ...t be secure and free of leaks Replace tubing if necessary TASK 2 Inspect exhaust lines for leaks or loose connections Remarks All exhaust lines must be covered with insulation TASK 3 Check fuel strainer for water and or other contamination Make sure that the fuel supply pipe is tightly connected to the unit and strainer Remarks Replace a plugged strainer with a new one TASK 4 Inspect the fuel pipe...

Page 19: ...ections as specified below 1 Inspection of Air Intake Exhaust Pipe A Visually inspect both the air intake and exhaust pipes for obvious cracks leaks or loose connections Black carbon deposits may be evidence of leakage B Be sure that all pipes are installed tightly and securely especially at the joints C Turn the heater on D Carefully apply a small amount of soapy water with a paint brush to the s...

Page 20: ...f the strainer is clogged replace it with a new one WARNING Before proceeding further unplug the heater When it has been determined that water or some other contaminants have infiltrated the fuel the following procedure should be used STEP 1 Remove contamination Drain the contaminants from tank or disconnect the fuel supply tube and clean the contamination from the fuel tank Refill with fresh and ...

Page 21: ...l lines will cause the coil line to break due to excessive current 5 The flue gas could leak through a crack of the ceramic part of the igniter and or a deteriorated igniter gasket and flow into the circulating hot air This will lead to a very strong odor 5 3 Burner Thermistor The burner thermistor senses the temperature of the burner When it detects an accidental reduction of the burner temperatu...

Page 22: ...F 6 ON OFF ON OFF 0 ON ON ON OFF 6 ON OFF OFF ON 12 ON ON OFF ON 18 ON OFF ON ON 24 ON ON ON ON 30 5 5 Burner Mat 1 This is attached to the burner bottom with the burner mat adhesive Betac 99C Part 20474926 This helps vaporize the fuel smoothly and stabilize the combustion when the unit is tilted 2 The burner mat is made of silica cloth its heat resistance limit 1000 C 1832 F and is expected durab...

Page 23: ...n Open at 90 C 5 C 195 F 9 F Close at 70 C 5 C 160 F 9 F 3 To restart resolve the cause of overheating and allow the heater to cool down Then push in the HEAT switch to ON 5 7 Blower Motor 1 This Direct current brushless motor generates the air pressure for both the air supply for combustion and circulation 2 Specification OUTPUT power for control DC 12V OUTPUT power for fan drive at high stage DC...

Page 24: ...not lit when turning on No Is wiring correct Correct wiring Red wire Yes Black wire No Check fuse Change fuse Yes No Check battery Recharge or replace battery DC 12V Yes No Check the Disconnected terminal terminal Yes Remote control malfunction or Main circuit board malfunction ...

Page 25: ...s No Check flame in Recharge or replace battery burner Yes Fuel pump malfunction Note 5 Igniter mounted incorrectly Note 6 Blower motor malfunction Extension cord too long Note 7 No Check flame rod Check and clean flame rod Note 3 Yes Failure of adjustment of fuel flow or Note 4 Main circuit board malfunction ...

Page 26: ...tallic part of the burner Note 4 Adjust the fuel flow in accordance with item 5 4 2 Note 5 In the event that there is no flame found in the burner the fuel pump probably cannot pump up the fuel which has been plugged with microsize dust or to the plunger lock which has been caused with water contamination in the fuel If this pump is assumed to have trouble replace the whole unit with a new one HOW...

Page 27: ...geometry of the D cut in the igniter is shown in the right hand figure If the D cut is installed in reverse the heater coil is located too far away from the ignition point to be ignited The igniter terminal is applied with approximately DC 11 5V at the time of ignition Note 7 If the power cord is extended excessively the heater may experience a voltage drop which may often cause ignition failure I...

Page 28: ... F B Constant Approx 20MΩ 70KΩ 31 5KΩ 5100 Note 2 The heater should be able to operate even with an extremely short or excess supply of fuel while it may occasionally operate when the combustion air is contaminated with emission gas Make sure that the flue pipe and the obstacle cover are free of any interfering substances for proper ventilation In case of extension of flue pipe and or installation...

Page 29: ...29 ...

Page 30: ...s when the power rises 17 2V while in operation HOW TO REPLACE IGNITER The igniter can be replaced when the heater is being installed 1 Unscrew each four A and C screws and remove the front panel and rear panel 2 Unscrew two E screws and two D hexagonal bolts and remove the cabinet B and under panel One of the two D hexagonal bolts should be left engaged with the cabinet in order to prevent the un...

Page 31: ... pushed into ON position the heater consumes a power of approximately 96W for ignition for approximately 3 minutes As the battery capacity decreases the voltage decreases lower than approximately 10V at the same time as ignition is made which causes heater operation to stop A heater operation similar to this failure may be caused by reduced battery capacity while in operation Check on the battery ...

Page 32: ...upply is caused Refer to item 5 4 2 6 7 Troubleshooting Guide VII Metallic or whistle noise Generally in case of an excessive fuel feed or a lack of combustion air supply the burner inside has long yellow flames This excessive fuel feed is considered to be caused by the fuel flow adjustment failure Refer to item 5 4 2 As for a lack of combustion air supply check on any abnormal extension of the fl...

Page 33: ...or the motor controller must be defective Ignition with an explosion Re igniting of the heater immediately after it has been extinguighed may be accompanied with an explosive noise Wait 20 minutes before re igniting White smoke Make sure the extension pipe joints are disconnected Connect the extension pipes correctly Odor Make sure the igniter gasket or other gasket are not damaged and or the scre...

Page 34: ...e pipes and the fuel tube from the unit and dismount the unit from the hanger by removing the two hexagonal bolts 13mm 1 2 in CAUTION Prevent dust or contaminants from being sucked into the fuel pump through the fuel pump inlet when removing the fuel tube Otherwise dust can clog the fuel pump 7 2 Cabinet and Panels a Front panel Remove four 4 screws b Rear panel Remove two 2 screws of clamps and r...

Page 35: ...e two 2 nuts of the fuel pipe 2 Hold the nipple with a wrench and loosen the nut with another wrench Note It is not necessary to remove the cabinet A CAUTION When reassembling 1 Start the nuts with hand and then tighten them with a tool 2 Be careful of fuel leakage 7 5 Fuel Nozzle 1 Remove the front panel and the cabinet B 2 Remove the nut and two 2 screws Pull the fuel nozzle out of the burner 3 ...

Page 36: ...TION Be careful to prevent dust from being sucked into the pump 7 7 Fuse 1 Remove the rear panel and the cabinet B 2 Pull out the fuse from fuse holder 7 8 Transistor 1 Remove the rear panel and the cabinet B 2 Disconnect the lead wire from the circuit board 3 Remove one 1 screw to remove the transistor 7 9 High Limit Switch 1 Remove two 2 screws from retainer ...

Page 37: ...ews from the top air duct supporter Remove the air hose and remove the top air duct supporter by spreading the top air duct side panel 3 Pull out the heat exchanger while spreading the top air duct side panel CAUTION When reassembling 1 Securely insert the air hose to the joint pipe of the blower motor case 2 Insert the two ears of the top air duct side panel to the slits of the top air duct top p...

Page 38: ...xing the top air duct to the blower motor case 3 Remove two 2 screws from the burner to remove the flame rod CAUTION When reassembling 1 Position the heat chamber first and then position the top air duct 2 Securely insert the rubber air hose to the joint pipe of the blower motor case 3 The connection for the flame rod maybe loose Be sure it is securely fastened to the burner assembly ...

Page 39: ...e bottom of the burner ring 7 14 Burner Mat 1 The burner mat is attached with heatproof adhesive BETAC Part 20474926 on the burner bottom When replacing it use with BETAC 7 15 Burner Assembly 1 Remove two 2 screws connecting the burner and the heater base 2 Remove the burner assembly from the heater base 7 16 Burner Thermistor 1 Disconnect the lead wire of the burner thermistor ...

Page 40: ...e and is very fragile 7 17 Blower Motor 1 Remove three 3 screws from the blower motor assembly Remove the air hose from the outlet joint of the blower motor This hose is just inserted onto the outlet joint 2 Remove three 3 screws from the air joint duct 3 Unfasten two 2 connectors of the motor controller and remove two 2 screws from it 4 Remove four 4 screws from the blower case joint ...

Page 41: ...ut clockwise 7 Pull off the circulation fan from its shaft by turning the nut counterclockwise 8 Remove three 3 screws from the blower base 9 Remove three 3 screws from the blower motor CAUTION When reassembling 1 Be sure air hose is in the proper position 2 Be careful to mount the fans in proper position ...

Page 42: ...42 Section 8 Circuit Board Specifications 8 1 Wiring Diagram ...

Page 43: ...43 8 2 Time Chart ...

Page 44: ...44 Section 9 Parts Description 9 1 Exploded View ...

Page 45: ...11 15 17185374 Igniter with gasket 51 17185379 Screw C1 16 17185850 Igniter gasket 52 17185360 Nut C2 17 17196315 Fuel nozzle 53 20474058 Nut A 17185342 18 17185541 Air hose 54 17185361 Screw C2 19 17196359 Pump fuel pipe 55 20476150 Washer E 17185350 20 17185320 Flame rod 56 20450040 Wing nut 17021705 21 17185514 Burner mat 57 17185362 Nut C3 22 20477443 Burner ring 17185491 58 17185364 Screw C3 ...

Page 46: ...46 9 3 Accessories ...

Page 47: ...TOYOTOMI U S A INC P O Box 176 604 Federal Road Brookfield CT 06804 0176 Rev 2 03 Printed in United States ...

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