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Form  RZ-NA  I-SCE,  Mfg  #207697  Rev  4,  Page  27

The gas train includes a single-stage gas valve, a modulating valve, and two gas pressure

switches. The burner rack is equipped with one flash carryover and a regulated gas lighter tube

system. The carryover lighter tube receives its gas supply through the regulator, simultaneously

with the gas to the burner. Control of the system is through a Maxitrol #ES410A amplifier with a

corresponding remote temperature dial (Maxitrol #ES410TD).

gu

gu

Carryover

Regulator

Modulating

 Valve

Single-Stage

Gas  Valve

P rimary Gas

Flow Pressure

Switch

White Label

1.1” w.c.

Gas Flow

Pressure Switch

White Label

1.1” w.c.

FIGURE 27 - Option

AG39 Manifold

Arrangement

Note: Arrangement  may  vary  slightly

depending  on  gas  valve;  components

are  the  same.

Description of the

Operation of Option

AG39

The gas supply (see pressure requirements in the table above) connects to the single-stage gas

valve. To compensate for additional pressure loss through the modulating valve, the single-stage

gas valve has a custom outlet pressure setting higher than when it is used on a standard gas

manifold. The pilot tubing connects to the pilot port on the single-stage gas valve. When the

valve receives a call for heat from the amplifier and pilot is established, gas flow from the single-

stage valve goes to both the modulating valve and the regulated lighter tube system. When the

signal from the amplifier to the modulating valve requires less-than-high fire operation, the modu-

lating valve functions to lessen the gas flow to the burner to reduce the input rate to that required

to maintain the desired temperature. When the input rate is reduced enough to decrease the gas

pressure to 1.1" w.c., the primary gas pressure switch in the manifold activates the gear motor that

controls the bypass damper in the venter/combustion air system. The bypass damper opens

diverting some of the incoming air directly into the flue duct, reducing airflow through the burner.

Safety switches monitor the position of the bypass damper. When the gas pressure increases

above 1.1" w.c., the bypass damper closes.

Combustion Air

Pressure Switch

Settings for Model

SCE with Option

AG39 or AG40

Sensor Location

For the convenience of the installer, the duct temperature sensor is factory installed in the cabinet

leg (See 

FIGURE 23

, page 25). Although the sensor has a mixing tube, at this distance from the

discharge it does not receive a true mix, so the temperature read by the sensor will be slightly

higher than the actual air entering the ductwork. The system will provide comfort level heat if the

selector is set slightly higher to compensate for this reading. If a direct correlation of these two

temperatures is required, move the duct sensor to a location in the ductwork about 10-12 feet (3-

3.7 M) from the furnace discharge.

Wiring and Service

For wiring, consult the wiring diagram attached to the furnace. All wires in the electrical box

connecting the modulation controls must have a temperature rating of 150°C.

This is a unique system which includes custom-built components and custom settings. If

service is required, follow the general troubleshooting guide on page 35 and the special trouble-

shooting guide in 

FIGURE 28

.

This uniquely designed modulation system requires combustion air pressure settings different

 

from the standard system. The

 

Sizes with

 

Startup

    

Equilibrium

 

Factory 

approximate  settings  for  the

 

AG39&40

 

Cold

 

at Full Rate

 

Setting

 

combustion air proving switch

 

125-225

 

-1.3"w.c.±0.2

   

-1.05"w.c.±0.1

   

-1.0"w.c.±0.

0

2

250-300, 400 -1.2"w.c.±0.2 -0.95"w.c.±0.1 -.7

0

"w.c.±0.

0

5

at sea-level operation are:

21D. Computer Controlled Electronic

Modulation between 20-28% and

100% Firing Rate (U.S. Patent

6,109,255), Option AG40 

- not available

on Size 350; available with natural gas only

With this option the furnace is equipped with a Maxitrol signal

conditioner (see illustration in 

FIGURE 26

) which accepts an

input signal of either 4-20 milliamps or 0-10 volts from a cus-

tomer-supplied control device such as a computer. With the dip

switches on the conditioner in the "on" positions, the condi-

Summary of Contents for Reznor SCE

Page 1: ...and 1 combustion air connections between the appliance and the outside atmo sphere and 2 flue gas connections between the appliance and vent cap of a type s specified by the manufacturer but supplied by the installer constructed so that when in stalled in accordance with the manufacturer s instructions air for combustion is obtained from the outside atmosphere and flue gases are discharged to the ...

Page 2: ...structures and apartment complexes The heaters are not certified as residential heating equipment and should not be used as such Clearances from the heater and vent to combustible construction or material in storage must conform with the National Fuel Gas Code ANSI Z223 1a latest edition pertaining to gas burning devices and such material must not attain a temperature over 160 F by continued opera...

Page 3: ...m N H 4 Mounting Sockets 1 IPS free turning female pipe thread 3 4 19mm 19 1 2 495mm 19 1 2 495mm 1 1 8 29mm 2 1 4 57mm 1 1 2 38mm 34 864mm 24 1 8 613mm 58 1 8 1 476mm 59 1 16 1 500mm 15 16 24mm 2 3 4 70mm L Gas Connection Electrical Connections G E 7 1 2 191mm M Combustion Products Discharge 6 150mm O D K 4 9 16 116mm Combustion Air Inlet 6 150mm I D 4 5 16 110mm 10 254mm J 19 1 2 495mm 2 1 4 57m...

Page 4: ...et bolts Motor Shipping Plate Units that are equipped with motors of 1 1 2 HP or less have a metal shipping plate attached between the motor and the blower housing The shipping plate must be removed and the plate and screws discarded On units factory equipped with an optional belt guard the belt guard must be removed to reach the shipping plate The concentric adapter assembly in the venting combus...

Page 5: ...226 254 Mounting Supports Model SCE requires six support locations See FIGURE 3 Supports available from the manufacturer P N 74487 or field fabricated legs as illustrated in FIGURE 4 may be used at the four corner support locations Do not use this type of support at the center support locations between the furnace and the blower section At the center locations a field fabricated angle iron brace s...

Page 6: ... is recommended of insulation Through Unheated Space Insulate all exposed warm air ducts passing through an unheated space with at least 1 2 1 is recommended of insulation Duct Supports Suspend all ducts securely from adjacent buildings members Do not support ducts from unit duct connections Duct Sizing Proper sizing of the supply air ductwork is necessary to ensure a satisfactory heating installa...

Page 7: ...nstructions The qualified service agency installing this separated combustion system is responsible for the installation Hazards of Chlorine The presence of chlorine vapors in the combustion air of gas fired heating equipment presents a potential corrosion hazard Chlorine found usually in the form of freon or degreaser vapors when exposed to flame will precipitate from the compound and go into sol...

Page 8: ... 6 152 6 152 30 15 8 2 4 4 1 2 7 178 7 178 70 21 8 2 4 4 1 2 Equivalent Straight Length for a 200 225 250 45 Elbow 300 350 400 Pipe Diameter andMaximum Pipe Length from Heater to Concentric Adapter Vent Pipe Inlet Air Pipe Maximum Length 90 Elbow Pipe Diameter SCE All pipe is field supplied Requirements are listed for both the vent pipe and the combustion air inlet pipe Vent pipe approved for a Ca...

Page 9: ...d joint Figure 9 STEP 3 Spaced equally around the double wall pipe drill three small holes below the sealant ring Insert 3 4 inch long sheetmetal screws to secure the joint Do not overtighten screws Make this connection a maximum of 6 152mm from the concentric adapter box 5 I D Double Wall Pipe 6 to 5 or 7 to 5 Taper Type Reducer DoSTEP2 immediately following STEP1 To seal joints in the single wal...

Page 10: ...iew showing Airflow Gray Arrows show Flow of Combustion Air Vent exhaust gas flows through field supplied double wall pipe that extends straight through the concentric adapter box P N 205885 Concentric Adapter Box Top View Heater Side View 6 Collar for Combustion Air Pipe Opening for vent pipe to pass through the box 2 51mm 2 51mm 6 1 32 153mm 8 dia Collar for Combustion Air Pipe 14 1 4 362mm 5 12...

Page 11: ... wall inlet air pipe attaches tot he heater 5 127mm inside diameter double wall vent pipe Top View of Concentric Adapter Box showing Pipe Connections 7 178mm diameter single wall or Category III vent pipe attaches to the heater 8 203mm diameter single wall inlet air pipe Model SCE 200 400 Pipe diameters and connections required at the concentric adapter box when using 7 pipes between the furnace a...

Page 12: ... pipe specified in Requirement No 1 page 8 Comply with requirements in Requirement No 2 and No 4 page 8 when attaching pipes to the heater Seal all joints Due to the high temperature do not enclose the exhaust pipe or place pipe closer than 6 152 mm to combustible material Extend the runs close to the wall location selected in Step 1 Support pipes as required in Requirement No 5 page 10 WARNING Al...

Page 13: ...ied 6 Position the inlet guard over the end of the combustion air pipe See FIGURE 13 page 14 Attach the guard to the inlet air pipe with the four 1 2 long screws provided 7 Determine length and install the double wall terminal vent pipe a Determine length of pipe The length of the vent pipe is determined by the installation within the maximum and minimum requirements The vent pipe extending throug...

Page 14: ...ch double vent pipe to vent run no more than 6 152mm from the box A taper type reducer is required 2 51mm if wall is combustible Attach box to wall with brackets One piece of Double Wall Vent Pipe 2 51mm 6 152 mm 1 25mm minimum 48 1219mm maximum Top View FIGURE 13 Installation of a Typical Separated Combustion Unit with Horizontal Vent and Combustion Air Pipes Option CC6 completely 10 Attach the i...

Page 15: ...re made in the box in error they must be sealed 2 Attach the Box to the Roof Step 5 When the box is attached to the roof in Step 5 use the 2 1 2 64mm portion of the brackets To adjust to construction each bracket has three 7 32 diameter holes Qty P N Description 1 205896 Complete Vertical Vent Kit Same as Option CC2 1 205885 Concentric Adapter BoxAssembly See FIGURE10 page 10 1 53326 Exhaust Vent ...

Page 16: ...uble Wall Vent Pipe b Attach the outside portion of the combustion airpipe to the box Determine the length of the combustion air pipe so that dimension X in FIGURE 15 is equal to the bracket length plus the roof thickness plus anticipated snow depth but does not exceed 48 1219mm or have less than 18 457mm of pipe above the roof Attach the inlet air pipe to the collar of the concentric adapter box ...

Page 17: ...38mm 11 279mm 18 457mm minimum 4 ft 1 2M maximum Roof Inlet air cap must be at least 6 higher than anticipated snow depth 2 51mm if roof is combustible Attach box to roof with brackets 12 305mm minimum Cold Climate NOTE In geographic areas where the design ambient is 10 F or lower this minimum height is 24 610mm Top of Box Combustion Air Pipe Concentric Adapter Box Roof Double wall Vent flue exhau...

Page 18: ...upply piping installation should conform with good practice and with local codes These separated combustion units for natural gas are orificed for gas having a heating value of 1000 50 BTUH per cubic ft If the gas at the installation does not meet this specification consult the factory for proper orificing Seal the opening for the gas supply pipe with the grommet provided Pipe joint compounds pipe...

Page 19: ...outlet pressure tap in the valve NOTE A manometer fluid filled gauge is recommended rather than a spring type gauge due to the difficulty of maintaining calibration of a spring type gauge 2 Open the valve and operate the heater Measure the gas pressure to the manifold To measure the low stage pressure on units equipped with a two stage valve disconnect the wire from the HI terminal on the valve Be...

Page 20: ... identified on the wiring diagram supplied with the heater FieldControl Wiring Length andGauge Total Wire Length Distance from Unit to Control Minimum Recommended Wire Gauge 150ft 46M 75ft 23M 18 gauge 250ft 76M 125ft 38M 16 gauge 350ft 107M 175ft 53M 14 gauge CAUTION If any of the original wire as supplied with the appliance must be replaced it must be replacedwithwiring material having a tempera...

Page 21: ...ES C 5 LINE AND BLOWER MOTOR BRANCH CIRCUIT WIRE SHOULD BE SIZED TO PREVENT VOLTAGE DROP BEYOND FIVE PERCENT OF SUPPLY LINE VOLTAGE 6 USE 14 GA WIRE FOR LINE AND MOTOR WIRING ON 3 PHASE UNIT FOR 208V UNITS USE BLACK AND RED LEADS CAP YELLOW ON 115 460V UNITS THE CONTROL TRANSFORMER IS A SINGLE VOLTAGE PRIMARY 9 ON 208 230V UNITS THE CONTROL TRANSFORMER HAS A DUAL VOLTAGE PRIMARY FOR 230V UNITS USE...

Page 22: ... GAS VALVES TO UNIT 1 ON A CALL FOR HEAT BY THE LOW STAGE OF THERMOSTAT A THE VENTER MOTOR IS ENERGIZED AFTER A 15 SECOND APPROX TIME DELAY B VENTER FLOW SWITCH SWITCHES FROM N C TO N O CONTACTS ENERGIZING THE PILOT GAS VALVE AND SPARK TO PRODUCE A PILOT FLAME ON EACH OPERATING CYCLE THE SENSING PROBE PROVES THE PRESENCE OF THE PILOT FLAME AND ENERGIZES THE SAFETY PORTION OF THE CONTROL THE SWITCH...

Page 23: ...f cold air b Blower operation continues after the thermostat is satisfied as determined by the fan time delay 2 To be sure that the blower can continue to operate the power supply to the furnace MUST NOT be interrupted except when servicing the unit 3 If the customer wants the furnace off at night the gas valve circuit SHOULD BE OPENED by a single pole switch wired in series with the thermostat So...

Page 24: ...d decreasing outlet temperature turn the adjustable half of the pulley inward To decrease the blower speed increasing the outlet temperature turn the adjustable half of the pulley outward One turn of the pulley will change the speed 8 10 5 Tighten the set screw on the flat portion of the pulley shaft 6 Replace the belt and adjust the belt tension Adjust tension by turning the adjusting screw on th...

Page 25: ...rature setting Depending on the option selection the factory installed sensor is either field connected by capillary tubing to the unit mounted ductstat FIGURE 24 or electrically connected to a remote electronic temperature selector FIGURE 25 The remote temperature selector is available with or without a display module See FIGURE 23 for a general location of the factory installed sensor with eithe...

Page 26: ...n the amplifier Option AG9 has a remote temperature selector Both systems are available with an override thermostat 21B Computer Controlled Electronic Modulation between 50 and 100 Firing Rate OptionAG21 With this option the furnace is equipped with a Maxitrol signal conditioner which operates much the same way as the amplifier above to control the regulator valve The conditioner accepts an input ...

Page 27: ...airflow through the burner Safety switches monitor the position of the bypass damper When the gas pressure increases above 1 1 w c the bypass damper closes Combustion Air Pressure Switch Settings for Model SCE with Option AG39 or AG40 Sensor Location For the convenience of the installer the duct temperature sensor is factory installed in the cabinet leg See FIGURE 23 page 25 Although the sensor ha...

Page 28: ... is there a steady voltage between Terminal 84 and Terminal 2 Replace the primary manifold pressure switch When the manifold pressure is ABOVE 1 5 w c is there a steady voltage between Terminal 95 and Terminal 7 Replace secondary manifold pressure switch Is there voltage between Terminal 4 of the ignition premissive relay and Terminal 7 Replace ignition permissive relay YES NO YES NO YES NO Sympto...

Page 29: ...me proven the ignition controller energizes the main gas valve CAUTION Due to high voltage on pilot spark wire and pilot electrode do not touch when energized See Hazard Levels page 2 Pilot All pilots are vertical target type with lint free feature Pilot flame should be approximately 1 1 4 in length Pilot gas pressure should be the same as the supply line pressure Pilot gas is supplied through the...

Page 30: ...at tests Blower Checks Check blower pulley and motor pulley to be sure they are secure to the shafts Check belt tension and alignment See Paragraph 17 Check the rotation of the blower See Paragraph 17 Verify the removal of all shipping supports See Paragraph 4 Check damper linkage See Paragraph 26 25 Check Installation and Startup Check the installation prior to startup 23 Burner Orifices cont d 2...

Page 31: ... proves the presence of the pilot flame and energizes the safety switch portion of the control The switch action de energizes the spark gap and energizes the main valve The main gas ignites and the unit fires at full rate c If the flame is extinguished during main burner operation the safety switch closes the main valve and recycles the spark gap On unit equipped with a G770NGC 4 controller which ...

Page 32: ...e air dampers the return damper linkage must be adjusted prior to use 1 Loosen the set screw on the return air damper rod at the damper arm 2 Manually open the return air dampers While the dampers are open ing the damper rod and arm will automatically move to their correct positions 3 Tighten the set screw FIGURE 31 Control Locations for Air Inlet Damper Options 1 OutsideAir Damper 2 ReturnAir Dam...

Page 33: ...d gas pressure has reached equilibrium close the manual shutoff valve Observe the gas pressure There should be no loss of gas pressure on the manometer If the manometer indicates a loss of pressure replace the combination gas valve before placing the heater in operation NOTE Operational pressure settings and instructions for checking pressure settings are in Paragraph 10 28 Operating Gas Valve Ins...

Page 34: ... the pilot hood with an emery cloth and wipe off the ceramic insulator Check the spark gap spark gap should be maintained to 100 After the pilot is cleaned blow any dirt away with compressed air Clean main burners and burner orifices using air pressure Use an air nozzle to blow out scale and dust accumulation from the burner ports Alternately blow through the burner ports and the venturi Use a fin...

Page 35: ... block off the distribution air The limit control should open within a few minutes shutting off gas supply to the main burners TROUBLE PROBABLE CAUSE REMEDY 1 No power to the furnace 1 Turn on power check supply fuses or circuit breaker 2 No 24 volt power to venter relay 2 Turn up thermostat check control transformer output Check for loose or improper wire connections 3 Venter relay defective 3 Re...

Page 36: ...gas pressure See Paragraph 10 d Cracked ceramic at sensor d Replace sensor e Faulty ignition controller e See Paragraph 31 If all checks indicate no other cause replace ignition controller Do not attempt to repair the ignition controller This device has no field replaceable parts 1 Dirty filters in blower system 1 Clean or replace filters 2 Incorrect manifold pressure or orifices 2 Check manifold ...

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