Service manual

ManualsBrandsModine Manufacturing ManualsGas HeaterPAE

December, 2003

SERVICE DIAGNOSIS

Modine heating & ventilating equipment

75-551.5

A Problem/Remedy Guide for

Modine:

Gas-Fired Unit Heaters

Gas-Fired Duct Furnaces

Steam/Hot Water Unit Heaters

Electric Unit Heaters

Oil-FIred Unit Heaters

Infra-Red Heaters

The Modine Service Diagnosis Guide was compiled as a

trouble shooting guide intended to define the most common

types of service problems found with heating equipment, the

possible causes of these problems, and possible remedies. This

trouble shooting guide, used in conjunction with the appropriate

product Installation and Service Manual, should enable a

serviceperson to identify, investigate and resolve most field

service problems found with industrial/commercial unit heaters.

Remember:

When servicing any unit heater locate the rating plate and

record the model number, power code number, control code

number, and serial number shown. This information is required

to identify components and date of manufacture.

If a service problem is encountered which can not be resolved

with the use of this service guide, and the appropriate

installation and service manual, further assistance can be

obtained by contacting your local Modine factory representative.

Summary of content (20 pages)

PAGE 1
75-551.5 December, 2003 SERVICE DIAGNOSIS Modine heating & ventilating equipment A Problem/Remedy Guide for Modine: Gas-Fired Unit Heaters Gas-Fired Duct Furnaces Steam/Hot Water Unit Heaters Electric Unit Heaters Oil-FIred Unit Heaters Infra-Red Heaters The Modine Service Diagnosis Guide was compiled as a trouble shooting guide intended to define the most common types of service problems found with heating equipment, the possible causes of these problems, and possible remedies.
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TABLE OF CONTENTS PROBLEM A. B. See Page UNIT WILL NOT OPERATE . . . . . . . . . . . . . . . . . . . .3 All Units Gas-Fired Units Oil-Fired Units Electric Units PILOT WILL NOT LIGHT OR STAY LIT . . . . . . . . . . .3 Gas-Fired Units Duct Furnaces Infra-Red Heaters C. PILOT FLAME NOT NORMAL . . . . . . . . . . . . . . . . .4 Gas-Fired Units Infra-Red Heaters D. BURNER WILL NOT LIGHT OR STAY LIT . . . . . .4, 5 Gas-Fired Units Infra-Red Heaters Oil-Fired Units E. F. BURNER FLAME IS NOT NORMAL . . .
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Problem A. Possible Remedy Unit Will Not Operate 1. Electrical circuit in open position. 1. Turn on power, turn up thermostat, or replace fuse(s) and reset disconnect. All Units 2. Defective or incorrectly adjusted thermostat. 2. Replace or adjust thermostat. 3. Defective or incorrect wiring. 3. Check wiring and connections. If necessary rewire unit according to Modine wiring diagram. 4. Inoperable or defective automatic controls. 4. Check controls and replace if required.
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Problem C. D. 4 Possible Cause Possible Remedy Pilot Flame is Not Normal 1. Lazy yellow flame 1. Pilot orifice too large. 1. Check orifice size. 2. Waving blue flame 2. Excessive draft at pilot. 2. Either move or shield unit from draft. 3. Small blue flame 3. Low gas pressure. 3. Check gas pressure and adjust as per manufacturer’s recommendations. 4. Flame being lifted off pilot burner 4. Gas pressure too high. 4. Check gas pressure and adjust as per manufacturer’s recommendations.
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Problem D. Possible Cause Possible Remedy Burner Will Not Light or Stay Lit (continued) 1. Burner motor runs but no spark. 1. Check electrode spacing or replace ignition transformer. Oil-Fired Units 2. Primary control locked out on safety. 2. Push reset button on primary control only if heat exchanger is cool. Try this only twice. See Control Service Instructions in Installation Manual. 3. Defective cad cell. 3. Replace cad cell if necessary. Check continuity. 4.
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Problem E. Possible Cause Possible Remedy Burner Flame is Not Normal (continued) Infra-Red Heaters 1. Gas burning at orifice. 1b. Replace ceramics. 1c. Loose or missing seal in ceramic mounting frames or under ceramics mounting frames. 1c. Inspect and replace if necessary. 1d. Warped burner or ceramic mounting frames. 1d. Replace. 2a. Low gas pressure. 2a. Check gas pressure and adjust as per manufacturer’s recommendations. 2b. Mis-aligned main burner orifice. 2b. Re-align burner orifice. 2c.
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Problem 1. Pilot Will Not Light or Stay Lit (continued). 2. Main Burner Will Not Light. Possible Cause Possible Remedy dd. Unit over fired. dd. Adjust to proper input. ee. Negative pressure in building. ee. Correct building negative pressure conditions. ff. ff. Blower drive not set correctly; blower running too slow. Adjust air blower per manufacturer’s recommendations. 2a. Defective electric operator. 2a. Replace. 2b. Gas valve turned to OFF or PILOT position. 2b. Turn to ON position. 2c.
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Problem Possible Cause Possible Remedy Gas-Fired Units Intermittent Pilot Ignition Systems (continued) 2. Pilot Lights, Main Burner Will Not Light. 2a. Turn to on position. 2b. System in lock-out mode. 2b. Reset system. 2c. Cracked or broken sensor ceramic. 2c. Replace sensor. 2d. Defective or loose connections to flame sensor or flame sensor lead. 2d. Correct or replace. 2e. Incorrect gas pressure. 2e. Check and adjust if necessary to manufacturer’s recommendations. 2f.
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Problem Possible Cause Possible Remedy Infra-Red Heaters Direct Spark Ignition Systems 1. No Spark. 2. Spark, but Main Burner Will Not Light. 3. Spark Stays on After Main Burner is Lit. I. 1a. Thermostat defective or incorrectly set heat anticipator. 1a. Check thermostat and anticipator setting. Replace thermostat if necessary. 1b. Ignitor ceramic cracked or broken. 1b. Replace. 1c. Incorrect spark gap. 1c. Check for proper spark gap or replace pilot ignitor. 1d. Poor ground connection. 1d.
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Problem 3. Motor Overheats or Burns Out. (continued) 4. Motor bearing failure. 5. Excessive belt wear on blower units. 6. Motor operates but fan or blower won’t turn. J. Oil-Fired Units Oil-Fired Units 3f. Check motor amp draw against nameplate amps. If amp draw exceeds nameplate amps redesign of duct work may be necessary. 3g. Incorrect blower rpm setting. 3g. Check blower rpm. Correct if necessary. 3h. Belt tension too tight on blower units. 3h. Check belt tension. 3i.
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Problem M. Burner Motor Operates but No Oil Delivered at Nozzle Oil-Fired Units N. Possible Remedy 1. Oil level below intake line inside supply tank. 1. Fill tank with oil and bleed air from the line. 2. Clogged strainer. 2. Remove and clean strainer. 3. Clogged nozzle. 3. Remove and clean or replace nozzle. 4. Air leak in the intake line. 4. Tighten all fittings in the intake line. Tighten unused intake port plug in the fuel unit.
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Problem P. Possible Cause Possible Remedy No Gas or No Oil Oil-Fired Units (continued) 8. Slipping or broken coupling. 8. Tighten or replace coupling. 9. Rotation of motor and fuel unit is not the same as indicated by arrow on pad at top of unit. 9. Install fuel unit with correct rotation. 10. Frozen fuel unit shaft. 10. Return unit to approved service station or factory for repair. Check for water and dirt in tank. 1. Loose pipe connections. 1. 2. Ruptured gas valve. 2. Replace. 3.
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Problem R. Steam/Hot Water Units 1. Blown fuses. 1. Replace fuses. Check for cause of blown fuses. 2. Defective element. 2. Replace element. 3. Burned out heating element. 3. Check element resistance with ohmmeter. 1. Dirty or clogged condenser. 1. Clean condenser. 2. Insufficient steam pressure or lack of hot water. 2. Check boiler capacity, pipe sizes and pump sizes. 3. Steam trap malfunctioning. 3. Repair or replace steam trap. 4. Condensate not draining from condenser. 4.
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Problem U. Possible Cause Possible Remedy Noisy Operation All Units 1. Loose screws or fasteners. 1. Tighten. 2. Bent sheet metal. 2. Repair or replace. 3. Fan bent or out of balance. 3. Replace. 4. Dirt on fan blades. 4. Clean fan. 5. Fan hub or blade rivets loose. 5. Replace fan. Gas-Fired Units 1. Noisy burner flame. V. 1a. Too much primary air. 1a. Adjust primary air. 1b. Burr in orifice. 1b. Remove burr or replace orifice. 1c. Burning in venturi. 1c.
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Problem X. Possible Cause Possible Remedy Noise of Ignition or Extinction Gas-Fired Units 1. Improper burner adjustment, damaged burner or obstruction. 1. See “Burner Flame is Not Normal,” pages 5, 6. Oil-Fired Units 1. Water in oil. 1. Bleed line at fuel unit. Replace supply if necessary. 2. Delayed ignition. 2a. Reset electrode gaps. 2b. Nozzle worn or dirty. Replace nozzle. 2c. Check voltage drop when burner motor starts. High current draw can result in weak spark from transformer. 2d.
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Problem Z. Possible Cause Possible Remedy Heat Exchanger Failure (continued) Gas-Fired Units 2. Localized burn-out of heat exchanger. Oil-Fired Units 2a. Damaged burner. 2a. Replace. 2b. Mis-aligned burner. 2b. Check burner alignment and correct. 2c. Improper air distribution over heat exchanger. 2c. Check duct design and correct. 2d. Air leaks from connecting duct work disturbing burner flames. 2d. Check for leaks. Tighten sheet metal screws.
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Problem AA. Unit Cycles on Overheat (high limit cycles) (continued) Possible Cause Possible Remedy 8. Improper duct design to and from unit (duct furnaces). 8. Check duct design and correct. 9. Air distribution baffle not in place on duct furnaces. 9. Check if baffle is required and install if necessary. 1. Conditioned air or make-up air over heat exchanger too cold resulting in high condensation rates. (Blower units or duct furnaces.) 1.
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Problem 5. Thermostat does not cycle often enough. 6. Thermostat appears to be out of calibration. 7. Room temperature swings excessively. 18 Possible Cause Possible Remedy 5a. Thermostat is not exposed to circulated air. 5a. Relocate thermostat. 5b. Heat anticipator is set too high (low voltage controls). 5b. Reset to match current draw of equipment being controlled. 5c. Thermostat does not have a heat anticipator (low voltage controls). 5c. Replace with thermostat with a heat anticipator. 5d.
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Heating Division • Modine Manufacturing Company • 1500 DeKoven Avenue • Racine, Wisconsin 53403-2552 Phone: 1.800.828.4328 (HEAT) • Fax: 262.636.1665 © Modine Manufacturing Company 2003 12/03 - 1.