Applied Air IOMDFCDFM-1 Operation Manual Download Page 27

Page: 27 / 44

– 27 –

TROUBLESHOOTING GUIDE

Modulating Discharge Temperature (MDT or MDT EXPERT) Controls

continued

Portions reproduced with permission from Maxitrol

Company

Symptom

Possible Cause

Field Test

Remedy

1. Inlet pressure too low.

2. Incorrect outlet pressure

adjustment of Pressure
Regulator.

Unit Enable Potentiometer
(MP-15) not set correctly.

Discharge Air
Temperature Sensor
(TS-03) not reading
correctly.

3. The Heating Discharge

Air Setpoint on
MDT-EXPERT Control
System is not set
correctly.

1. Short circuit in

modulator coil.

2. Short circuit between

amplifi er and modulator
valve.

1. Read pressure at inlet to

modulating valve using
a manometer with unit
operating at full fi re.
Pressure should be equal
to the sum of outlet pressure
setting plus pressure drop
of the valve.

2. Read manifold pressure

using manometer and
compare with the pressure
stated on the specifi cation
plate.

1. Check setpoint on Unit

Enable Potentiometer
(MP-15)

2. Check Discharge Air

Temperature Sensor (TS-03)
and wiring. See Thermistor
curve.

3. Check setpoint with BACview

or PC.

1. Measure resistance across

modulator terminals with red
lead wires disconnected.

2. Inspect wiring.

1. Increase inlet pressure if

possible.

2. See valve adjustments in

Section X.

1. Change to correct setpoint

setting.

2. If readings are not correct,

replace Discharge Air
Temperature Sensor (TS-03)
or repair wiring.

3. Change to correct setpoint.

See Digital Control System
User Manual.

1. Replace modulator head if

less than 40 ohms.

2. Correct wiring if short is

found.

G. Incorrect

Maximum Fire.

H. Incorrect

Discharge Air
Temperature

I. Burned

out

Transformer.

(Refer to Digital Control System User Manual for additional troubleshooting suggestions)

Summary of Contents for IOMDFCDFM-1

Page 1: ...errupteur 3 Éteindre toute flamme ouverte 4 Appelez immédiatement votre fournisseur de gaz AVERTISSEMENT Une installation déficiente de même qu un mauvais réglage modification entretien ou maintenance peuvent occasionner des dommages matéri els corporels voire causer la mort Lire attentivement les instructions d installation d utilisation et d entretien avant d installer ou d intervenir sur cet ap...

Page 2: ...ion company when the claim is filed They will give you disposition instructions Packing We comply with the packing requirements of the transportation companies and your bill of lading proved that everything was in good condition when shipped That bill of lading contract requires them to deliver in perfect condition SECTION I FOREWARD As is the case with any fine piece of equipment care must be tak...

Page 3: ... it should be protected from the weather with tarpaulins or plastic coverings Do not assume that simply covering a unit will keep insects dust and condensation out of the unit and critical components Rotate the fan s monthly Prior to beginning installation of a unit that has been in storage for weeks or months the unit and its components should be closely inspected Shipments are made F O B Dallas ...

Page 4: ...ectrical Code and applicable local codes in Canada to the Cana dian Electrical Code Part 1 CSA Standard C22 1 The following recommendations are not intended to sup plant any requirement of federal state or local codes having jurisdiction Authorities having jurisdiction should be consulted before installations are made Lo cal codes may require additional safety controls and or interlocks All instal...

Page 5: ...m the factory Use extreme caution in handling the curb Proper han dling and positioning will assure a water tight curb unit installation Re check approval prints prior to installation Be sure that there are no obstructions to ducting and that proper planning has been exercised in connection of piping and or electrical services The curb assembly may be bolted or welded to either trusses or roof dec...

Page 6: ...unité devait être remplacé il doit être remplacé avec des câbles prévus pour résister à une chaleur d au moins 105 C F Field Piping Gas Piping All gas piping must be in accordance with the require ments outlined in the National Fuel Gas Code ANSI Z223 1 It is required that a ground union be installed adjacent to the manifold for easy servicing A drip leg and or filter should be provided upstream o...

Page 7: ...pstream connection and low side to the downstream connection of the Airflow Station as shown in Drawing C000643 below Be sure that all tubing is clean and clear of any debris before installing tubes on the transducer Refrigerant Piping Evaporator Coil Blow Through The cooling coil section is located in the unit so that the supply air is blown through the evaporative coil s A properly piped trap sh...

Page 8: ...TIONS TO TRANSDUCER PT 15 IN UNIT CONTROL ENCLOSURE 10 30 09 C000659B DRAIN PAN NOTE G TO BE A MINIMUM OF 1 2 PLUS THE TOTAL SYSTEM STATIC PRESSURE W C J TO EXCEED THE POSITIVE STATIC PRESSURE IN W C OF THE SECTION OF THE UNIT WHERE THE DRAIN IS INSTALLED PVC ADAPTER FITTING FPT x SLIP NIPPLE 10 30 09 C000659B DRAIN PANS UNDER A POSITIVE PRESSURE SUGGESTED P TRAP DESIGN FOR CONDENSATE G J PVC PIPE...

Page 9: ...the standing roof seam Fig 3 and side seams where the sections come togeth er Fig 1 It is mandatory to seal the roof and side seams along the entire outside of the unit and it is strongly suggested that the seams also be sealed along the inside of the unit if possible 4 Apply caulking material along the top of both sides of the standing roof seam Fig 4 Place roof cap Fig 4 on top of the seam and s...

Page 10: ...its are in the normal operating position 12 Check that system duct work is installed and free from obstructions 13 Check that fans turn free in housing 14 Check that the area around the unit is clear of flammable vapors or containers of flammable liquids 15 Check that all piping connections particularly unions are tight Check all gas piping for leaks using a soap bubble solution The most common ty...

Page 11: ... call for heat 3 Watch for ignition spark following prepurge See IP module specifications 4 Time the length of the spark operation See the IP module specifications 5 After the module locks out open the manual gas cock and make sure no gas is flowing to the pilot or main burner 6 Reset the flame safeguard relay RE 02 7 Operate system through one complete cycle to make sure all controls operate prop...

Page 12: ...fferent functions that control the fans and unit operation They are a Time Clock Heating and Cooling Night Setbacks and signal from an external source to an auxiliary digital input To disable the fans go to Unit Modes and enter OFF NOTE A BACview or PC is required to change Unit Modes For a more detailed control sequence see the Digital Control System User Manual If power supply meets requirements...

Page 13: ...erature if you have disconnected plug wiresTS 01 andTS 03 Referred to in Section X NOTE 3 OR 4 TRIALS MAY BE NEEDED TO PURGE AIR FROM PILOT LINE IF BURNER HAS MAIN FLAME ROD OR SCANNER YOU WILL NEED TO DISABLE TIMER CIRCUIT RE 75 NOTE Pilot regulator adjustment may be needed if the adjustment of the needle valve does not yield the required reading Typical adjustment of the needle valve is 1 1 2 to...

Page 14: ...low into the switch connection Switch operation will shut off the burner Recycle is automatic when the sensing tube is replaced The low air pressure switch is checked by removing the sensing tube from the leaving air side of the burner Switch operation will shut off the burner Recycle is automatic when the sensing tube is replaced E Adjustable Temperature and Limit Controls The limit controls are ...

Page 15: ... valve terminal is energized RM7897A e Delayed second stage main valve terminal is energized RM7897C f Internal system fault occurred g Purge card is removed h Purge card is bad 5 MAIN FLAME ESTABLISHING PERIOD MFEP RM7897A teminal 21 a Airflow lockout feature is enabled and the airflow switch opens b Ignition terminal is energized c Ignition pilot valve terminal is not energized d Main valve term...

Page 16: ...sence of flame the main fuel valve terminal 9 is powered If a flameout occurs the relay module locks out or recycles depending on status of jumper JR2 within 0 8 or 3 seconds depending on the Flame Failure Response Time FFRT of the amplifier b The RM7897A terminal 21 has a ten second MFEP After the Ignition Trials the interupted pilot valve terminal 8 is de energized If a flameout occurs the relay...

Page 17: ... SERVICE NOTE Clipping and removing a site con figurable jumper enhances the level of safety Figure 5 Sequence Status LEDs Figure 6 Selectable Site Configurable Jumpers Table 7 Site Configurable Jumper Options Jumper Number Description Intact Clipped JR1 Pilot Flame Establishing Period PFEP 10 Seconds 4 Seconds JR2 Flame Failure Action Recycle Lockout JR3 Airflow Switch ILK Recycle Lockout Failure...

Page 18: ...ECTOR SEE FLAME DETECTOR SPECIFICATIONS FOR CORRECT WIRING PROGRAMMED ON SETUP USING S7800A1142 DISPLAY PURGE TIME DEPENDS ON WHICH ST7800 IS INSTALLED 3 3 4 5 PREIGNITION INTERLOCK 10 SECOND INTERRUPTED PILOT POWER OPERATING CONTROLS AND INTERLOCKS BURNER FLAME SIGNAL INITIATE INITIAL POWERUP ONLY POWER STANDBY POWER PILOT FLAME MAIN PFEP 10 SEC 4 SEC IF JR1 CLIPPED POWER MFEP PILOT FLAME MAIN RU...

Page 19: ... sure they are functioning properly 5 Inspect the Airflow Switch and make sure that it is functioning properly 6 Check the flame detector sighting position reset and recycle Measure the flame signal strength Verify that it meets specifications If not refer to the flame detector and or flame amplifier checkout procedures in the installation instructions 7 Replace the flame amplifier and or the flam...

Page 20: ...t VPS connected to terminal 16 is functioning properly replace if necessary 4 Reset and sequence the relay module 5 If fault persists replace the relay module 1 Make sure the purge card is seated properly 2 Inspect the purge card and the connector on the relay module for any damage or contaminants 3 Reset and sequence the relay module 4 If the fault code reappears replace the purge card 5 Reset an...

Page 21: ...quence the relay module 3 If fault does not repeat on the next cycle check for electrical noise being copied into the relay module through the external loads or possibly an electrical grounding issue 4 If the fault persists replace the relay module 1 Check wiring and operation of special OEM inputs 2 Reset and sequence the relay module 3 If fault reappears remove power from the device reapply powe...

Page 22: ...heck power source 2 Check and replace 3 Close or connect customer inter lock 4 Enable the fan 5 Check time clock night setback thermostat and field installed con trols for proper settings 6 Reset freeze stat by interrupting power Check for proper setpoint and burner operation 7 See Digital Control System User Manual 8 Check power source and or re place 9 Check for power at damper motor and that en...

Page 23: ...ame rod is in main flame check wiring and flame rod 5 Check for power and or replace 1 Manual pilot shut off valve closed 2 Inlet gas pressure lower than required gas pressure 3 No gas through pilot regulator with inlet gas pressure ok 4 No gas through pilot solenoid 5 Type of gas natural LP supplied different from factory required type Note components may change 6 Flame detection system not spark...

Page 24: ...ectly 4 Unit Control Module UC 01 defective 5 Unit Control Module UC 01 not wired correctly 6 Damper motor defective 7 Dampers binding and or loose 1 Building Pressure Transducer PT 13 Damper Control Potentiometer or null switch defective or not calibrated 2 Building Pressure Transducer PT 13 Damper Control Potentiometer or null switch not wired correctly 3 Building Pressure Transducer PT 13 Dampe...

Page 25: ... 1 signal conditioner provides signal conversion for a high impedance 2 10VDC signal source to drive a 24VDC solenoid The control should be powered by an isolated 24VAC transformer to drive up to a 5A dc solenoid Power Status LED A solid green LED indicates power and normal operation A slow blinking green LED indicates power but the 10 second start up delay has not completed A fast blinking green ...

Page 26: ... RE 26 terminals 7 8 2 Check item B1 Check for 0 10 VDC input signal from UC 01 at terminals 1 2 Check for 0 20 VAC output signal to gas valve at terminals 5 6 3 Check DC Voltage on AO 1 4 Inspect 1 Measure resistance across modulator terminals 5 6 with connecting wires detached 2 Inspect Plunger should be installed to operate freely in solenoid sleeve 1 See valve adjustments in Section X 2 Close ...

Page 27: ...plus pressure drop of the valve 2 Read manifold pressure using manometer and compare with the pressure stated on the specification plate 1 Check setpoint on Unit Enable Potentiometer MP 15 2 Check Discharge Air Temperature Sensor TS 03 and wiring See Thermistor curve 3 Check setpoint with BACview or PC 1 Measure resistance across modulator terminals with red lead wires disconnected 2 Inspect wirin...

Page 28: ...d check limit controls for normal operation 1 Arrow on side of valve should point in direction of gas flow 1 Remove wires connected to amplifier terminals 5 6 and measure resistance MR212 60 80 ohms M611 45 55 ohms 2 Inspect plunger should be installed to operate freely in solenoid sleeve 3 Disassemble valve for inspection of internal parts 1 Check for 24V AC at amplifier terminals 7 8 2 Measure r...

Page 29: ...it in Discharge Air Temperature Sensor TS 03 2 Incorrect Maximum Heating Discharge Temperature Setpoint 1 Short in modulator coil circuit 1 Incorrect Minimum Heating Discharge Temperature Setpoint 2 Incorrect space setpoint 3 Insufficient burner capacity G Continuous High Fire Electronics Problem H Continuous High Fire Electronics OK I Incorrect High Fire J Continuous Maximum Discharge Air Tempera...

Page 30: ... are energized and condensing unit or evaporative cooler is not on C Incorrect Space Temperature 1 Enable the cooling mode 2 Check auxiliary circuit wiring and contact 3 Adjust the air flow and external static pressure to match the unit rating plate DO NOT ADJUST SWITCHES 4 Change to correct setpoints See Digital Control User Manual 5 See Digital Control System User Manual 1 Check and or replace 2...

Page 31: ...ow Station Pressure Transducer PT 15 1 Remove the tubes at the Low and High pressure fittings 2 The voltage at COM and OUT should be O VDC If not adjust Z do not adjust S 3 Make sure the Low and High fittings are clean do not insert any sharp objects into the pressure fittings make sure the static pressure sensing pitot tubes and all tubing is also clean clear of any debris and then reinstall the ...

Page 32: ...Some adjustments can be made by repositioning the burner profile plates If the velocity will allow the High Velocity Switch to open you can open the profile plates If the velocity will allow the Low Velocity Switch to open you can close the profile plates REMEMBER to keep the opening between the burner and profile plates the same on both top and bottom of the burner when making these adjustments D...

Page 33: ...ILURE SW 72 RS 01 100 OA or 100 OUTPUT IN 4 RE 27 RS 04 BURNER STATUS RE 65 RS 03 FAN STATUS RE 12 TO GND RS 02 CLOGGED FILTER SW 09 RS 01 1 36 1 73 1 87 1 92 1 36 1 73 1 87 1 92 AUXILIARY UNIT ENABLE MULTIPLEXED VOLTAGE VALUES CHECK ALL TERMINAL CONNECTIONS FOR TIGHTNESS The DC voltage is to be checked at the UC 01 board With the Fan Enabled When the fan status relay RE 65 is energized the contac...

Page 34: ...or latches p Check that cabinet is weathertight replace door gas kets and recaulk as necessary NOTE Keep screened air intakes clear of obstruc tions at all times WARNING Failure to comply with the general safety information may result in extensive property damage severe personal injury or death Periodic maintenance is essential to the efficient operation and extended service life of this equipment...

Page 35: ... been pre lubricated with high quality lithium complex base grease with an EP additive The grease is a lithium complex base mineral oil NLGI Grade 2 consistency with a base oil viscosity of ISO VG220 Re lubrication should be done with lithium complex thickened grease with a compa rable NLGI consistency and base oil type and viscosity Wipe all grease fittings clean before adding grease Grease shoul...

Page 36: ...s end of the shaft by pushing on the inner ring Do not use a hammer 10 Slide the shaft through the next blower wheel hub and add another bearing Continue this procedure until the shaft is through all of the blower wheels 11 Place a bearing on each end of the shaft 12 Replace the shims as required 13 Install bearing mounting bolts do not tighten and check alignment 14 Tighten the bearing bolts to r...

Page 37: ...ed when the differential pressure across them reaches the manufacturer s recommended final value Dirty filter elements should be replaced with a clean element of the same type and size In addition the factory not only suggests but insists that air filters be checked every 30 days daily in icy or snowy weather and replaced with new filters throw away type or cleaned washable type as required Cleana...

Page 38: ...er supply so there can be no accidental start up during inspection b Inspect the burner carefully including upstream and downstream sides of mixing plates as well as burner body face Note that complete burner assembly may have to be removed for proper inspection and cleaning Any accumulation of scale or foreign material on either side of the mixing plates should be removed with a wire brush Check ...

Page 39: ...dequate once the initial piping debris is removed The operating conditions of the burner will determine how frequently maintenance is actually required P001117C Mestek Line Burners Use of an electric drill motor is not suggested unless both Pin Vise and Drill can be chucked up in a vari speed drill unit Use caution because it is easy to snap the bits off in a port when using a drill motor Removal ...

Page 40: ... WITH DDC MR212 High Fire Manifold Adjustments Note Low fire may need to be set first to get the burner to light off properly 1 Disconnect the plug where the Temperature Sensors TS 01 and TS 03 are wired to the unit control module UC 01 A minimum of 15vdc is required at terminals 5 and 6 on electric relay RE 26 This causes the valve to call for continuous high fire Caution The unit will shut down ...

Page 41: ...e voltage Above approximately 15 volts DC the Valve should be delivering full flow to the heater and the unit should be on full fire If the DC voltage is obtained on the Valve terminals but the heater does not respond as described the problem can be isolated to the valve itself or to the gas control manifold of the heater If the proper voltages are not obtained the problem can be isolated to the e...

Page 42: ...entilation requirements for the facility must be ad dressed separately The heater inlet shall be located in accordance with applicable building code provisions for ventilation air Field constructed intake accessories should be prop erly designed to minimize the entry of snow and rain All ventilation air to the heater shall be ducted directly from the outdoors If in doubt regarding the application ...

Page 43: ... 43 ...

Page 44: ...4830 Transport Drive Dallas TX 75247 Phone 214 638 6010 Fax 214 905 0806 www appliedair com ...

Search results

Summary of Contents for IOMDFCDFM-1

Reviews:

Related manuals for IOMDFCDFM-1

Brands by name

Popular brands

Applied Air IOMDFCDFM-1, Operation Manual

Search results

Summary of Contents for IOMDFCDFM-1

Reviews:

Related manuals for IOMDFCDFM-1

Brands by name

Popular brands