Service Guide. Service Guide NATIONAL COMFORT PRODUCTS GAS & ELECTRIC MODELS. 2nd Edition

Transcription

1 2nd Edition Service Guide Thru-the-Wall Packaged Heating & Cooling Units Service Guide GAS & ELECTRIC MODELS NATIONAL COMFORT PRODUCTS HEATING & A/C EQUIPMENT National Comfort Products A Division of National Refrigeration and Air Conditioning Products, Inc.

2 Table of Contents Model Number Identification... Page 3 Dimensions... Page 4 Gas Furnace... Page 5 Gas Furnace Specifications A, B, C Models... Page 6 Gas Furnace Specifications D and U Models... Page 7 Electric Furnace... Page Chassis (Cooling Section)... Page Wiring Diagrams... Page 47 2

3 Comfort Pack Model Number Identification *Note: Standard units (with no options) will have no letter after the U in the name. Example: CPG41838-U Model Number Options, if used C P G U * * * Last 2 Digits for factory use CP=Comfort Pack G =Gas E =Electric * * = Edition = Generation 4=410A Refrigerant Nominal Cooling Capacity 12=12,000Btu 18=18,000Btu 24=24,000Btu 30=30,000Btu Heating Capacity Gas Input 38=38,000Btu 51=51,000Btu 64=64,000Btu Electric 05=5 Kilowatt 07=7.5 Kilowatt 10=10 Kilowatt 15=15 Kilowatt A=No Grille B=Slotted Filter Door C=No Grille, with Slotted Filter Door U=Universal Chassis 3

4 Dimensions Note: Unit must be mounted a minimum of 8 above finished floor. 31 7/16" 7 11/16" 1 3/32" 20 1/8" 28" 3 3/4" 15 13/16" 11 1/16" Supply 26 9/32" Low voltage thermostat connection 1 23/32" 4 11/32" Junction box Gas Connection 43" 7 15/16" OPENING Return Drain 7 3/4" FRONT TO DRAIN TUBE 23 9/16 24" OPENING 15/ /16 OPENING 4

5 Gas Furnace Important Note! All CPG (GAS MODELS) come equipped with the interlock door switch. This switch is located behind the bottom filter access panel on the left hand side of the unit. When the filter access panel is removed this switch will open disconnecting all low voltage to the control board. This will shut down the unit but will not disconnect any active voltage inside the chassis section of the Comfort Pack. Interlock Door Switch Gas Furnace Components 1. Heat Exchanger 2. DSI Control Board 3. Venter Motor (Housing & Flue) 4. Burner Assembly (Single Orifice) 3 5. Furnace Safeties (Pressure Switch, Rollout Switch, High Limit Switch) not shown 6. Gas Valve (Factory Set for Natural Gas) 7. Flame Sensor - not shown DSI Electrode (Spark Ignitor) - not shown 5

6 Gas Furnace Specifications for A, B, C Models Gas Valve Setting 3.5 w.c. HEAT MODULE INPUT BTUH 38,000 51,000 64,000 OUTPUT BTUH 30,400 40,800 51,200 MAXIMUM EXTERNAL STATIC PRESSURE DISCHARGE TEMPERATURE RISE RANGE BLOWER SPEED SETTING.5" W.C..5" W.C.5" W.C 40 F to 70 F 40 F to 70 F 50 F to 80 F Low Medium High To ensure safe operation and long life of the heat exchanger, the maximum static pressure and/or maximum temperature rise must not be exceeded. Operation of the heater at conditions that exceed the heater s specifications will void the heat exchanger warranty MODEL SIZE ORIFICE SIZE N.G ORIFICE SIZE L.P mm 41 NOMINAL TEMPERATURE RISE CO 2 %- ACCEPTABLE RANGE 55 F 55 F 65 F 4.5 to to to 5.5 CO AIR FREE - PPM SENSING COLD / / /-.1 PRESSURE HOT.8+/ / /-.05 EFFICIENCY RANGE 81.5% % 81.5% % 80.1% % STACK TEMPERATURE 245 F- 300 F 245 F- 300 F 270 F- 330 F Temperature Rise Range Based On Return Air Temperature 6

7 Gas Furnace Specifications for D and U Models Gas Valve Setting 3.5 w.c. HEAT MODULE IINPUT BTUH 38,000 51,000 64,000 OUTPUT BTUH 30,400 40,800 51,200 MAXIMUM EXTERNAL STATIC PRESSURE DISCHARGE TEMPERATURE RISE RANGE BLOWER SPEED SETTING.5" W.C..5" W.C.5" W.C 45 F to 60 F 45 F to 65 F 60 F to 80 F Med. Low* (4-Black) Med. High* (2-Yellow) *See Wiring Diagram on Page High* (1-Red) To ensure safe operation and long life of the heat exchanger, the maximum static pressure and/or maximum temperature rise must not be exceeded. Operation of the heater at conditions that exceed the heater s specifications will void the heat exchanger warranty MODEL SIZE ORIFICE SIZE N.G ORIFICE SIZE L.P mm 41 NOMINAL TEMPERATURE RISE CO 2 %- ACCEPTABLE RANGE 52.5 F 55 F 67 F 4.5 to to to 5.5 CO AIR FREE - PPM SENSING COLD / / /-.1 PRESSURE HOT.8+/ / /-.05 EFFICIENCY RANGE 81.5% % 81.5% % 80.1% % STACK TEMPERATURE 245 F- 300 F 245 F- 300 F 270 F- 330 F Temperature Rise Range Based On Return Air Temperature 7

8 Gas Furnace Sequence of Operations (Gas Heat) 1. Call for Heat The thermostat sends a call for heat therefore energizing the white wire to the control board. The control checks to see that the limit switch is closed and the pressure switch is open. If the limit switch is open, the control responds as defined in the Limit Switch Operation - page 10. If the pressure switch is closed, the control will do four flashes on the green LED and wait indefinitely for the pressure switch to open. If the pressure switch is open, the control proceeds to (2.) Pre-purge. 2. Pre-purge The control energizes the venter motor and waits for the pressure switch to close. If the pressure switch does not close within 240 seconds of the venter motor energizing, on 3 attempts,the control green LED will flash two times and will enter a soft lock out. When the pressure switch is proven closed, the control begins the pre-purge time. If flame is present any time while in pre-purge, the pre-purge time is restarted. If flame is present long enough to cause lockout, the control responds as defined in Undesired Flame - page 20. The control runs the venter motor for a 20 second pre-purge time, then proceeds to the (3.) Ignition Trial Period. 3. Ignition Trial Period The control energizes the spark and main gas valve. The venter remains energized. If flame is sensed during the first 16 seconds, the spark is de-energized and the control proceeds to (4.) Heat Blower On Delay. If flame has not been sensed during the first 16 seconds, the control de-energizes the spark output and keeps the gas valve energized for an additional one second flame proving period. If flame is not present after the flame proving period, the control de-energizes the gas valve and proceeds with ignition re-tries as specified in Ignition Retry - page 9. If flame is present, the control proceeds to the (4.) Heat Blower On Delay 4. Heat Blower On Delay The control waits for 30 seconds from the time the gas valve opened and then energizes the blower motor. The gas valve and venter motor remain energized. The control proceeds to (5.) Steady Heat. 5. Steady Heat The control continuously monitors to the safeties (high limit, roll-out, and pressure) for open switches, flame sensor for proving, and the thermostat for a call for heat. When the thermostat call for heat is removed, the control de-energizes the gas valve and begins (6.) Post-purge and (7.) Blower Off Delay. 6. Post-purge The venter motor output remains on for a 45-second post-purge period after the thermostat is satisfied. 8

9 Gas Furnace 7. Blower Off Delay The blower motor is de-energized after a blower off delay (90 second factory setting, field adjustable, see page 23). Timing begins when the thermostat is satisfied. Abnormal Functions Interrupted Thermostat Call for Heat If the thermostat demand for heat is removed before the flame is recognized, the control will run the venter motor for the post purge period and de-energize all outputs. If the thermostat demand for heat is removed after successful ignition, the control will de-energize the gas valve, run the venter motor through post purge, and run the blower motor on heat speed for the selected delay off time. Soft Lockout The control shall not initiate a call for heat or call for continuous fan while in lockout. The control will still respond to an open limit and undesired flame. Lockout shall automatically reset after one hour. Lockout may be manually reset by removing power from the control for more than one second or removing the thermostat call for heat for more than one and less than 20 seconds. Hard Lockout If the control detects a fault on the control board, the status LED will be de-energized, and the control will lockout as long as the fault remains. A hard lockout will automatically reset if the hardware fault clears. Power Interruption During a momentary power interruption or at voltage levels below the minimum operating voltage for line voltage the system will self-recover without lockout when voltage returns to the operating range. During a momentary power interruption of low voltage the board will enter a soft lockout. Power interruptions of less than 80mS shall not cause the control to change operating states. Power interruptions greater than 80mS may cause the control to interrupt the current operating cycle and re-start. Ignition Retry If flame is not established on the first trial for ignition, the control de-energizes the gas valve and the venter motor remains energized for an inter-purge period of 20 seconds. The spark and gas valve are then re-energized, and the control initiates another trial for ignition. If flame is not established on the second trial for ignition, the control de-energizes the gas valve, energizes the blower motor on heat speed, and venter motor remains energized. The blower motor is shut off after a short period. When the blower motor de-energizes, the spark and gas valve are re-energized and the control initiates another trial for ignition. (This blower delay is a self-healing feature for an open auxiliary limit switch). If flame is not established on the third trial for ignition, the control de-energizes the gas valve, and the venter motor remains energized for an 9

10 Gas Furnace inter-purge period of 10 seconds. The control then re-energizes the gas valve and spark and initiates another trial for ignition. If flame is not established on the fourth trial for ignition (initial try plus 3 re-tries), the control de-energizes the gas valve and goes into lockout. The control goes to one flash on the green LED to indicate ignition failure lockout. Safety Switches Roll Out and High Limit Limit Switch Operation The limit switches are ignored unless a call for heat is present (W energized). If the limit switch is open and a call for heat is present, the control de-energizes the gas valve and turns the blower motor on heat speed and runs the venter motor. The control will be in soft lockout and flashing fault code 3 before returning to normal operation. When the switch re-closes or the call for heat is lost, the control runs the venter motor through post purge and runs the blower motor through the selected fan off delay. Slide-Out Furnace Instructions All Models after Serial # feature the Slide-Out Furnace option. 1. Remove the (4) screws indicated at the right. Gas Line Power Cord 10

11 Gas Furnace 2. Remove the patch plate. Gas Line Power Cord 3. Remove (2) right side screws and remove the front furnace baffle. Front Furnace Baffle Slide-Out Instructions continued on next page. 11

12 Gas Furnace Slide-Out Instructions continued. Gas Line Power Cord Pull Forward 4. Unplug (2) molex plugs before sliding out the heat exchanger/furnace assembly. 5. Grasp the vertical heat exchanger partition firmly with your left hand. Be careful not to tear the side and bottom insulation when pulling the heat exchanger/furnace assembly forward. Lift 6. With your right hand reach under the burner box and lift the drain pan to release the drain plug. Then lift up and pull the assembly forward to slide out the heat exchanger/ furnace assembly. 12

13 Gas Furnace High Limit Switch The high limit switch protects the furnace from overheating due to lack of indoor airflow. This switch breaks a circuit back to the DSI control board when tripped. The High Limit Switch is located above the collector box and mounted with (2) 1/4 screws. The High Limit Switch is normally closed, opens at 160 F +/- 5 F with an automatic reset differential of 60 F and is wired in series with the rollout switch. To prove the high limit switch has failed open, use an ohmmeter and verify there is no continuity across the terminals once the limit has cooled below the differential setting. If the unit is experiencing high limit failures or constant tripping verify your temperature rise (see page 14) and check for the following: Restricted airflow Blocked or dirty air filter Blocked or dirty return air grille Blocked supply duct (closed fire dampers) Blower motor not running (weak capacitor, low voltage) Overfiring or Oversized Gas pressure higher than 3.5 w.c. at outlet of gas valve Undersized ductwork (high static pressure or low cfm) 13

14 Gas Furnace Check Your Temperature Rise AS CLOSE AS POSSIBLE TO THE EVAPORATOR COIL BEHIND THE FILTER DOOR *Example shown has a ducted return Models A, B, and C The temperature rise should be as follows: 38MBTU = 55 F Nominal (40 F to 70 F) 51MBTU = 55 F Nominal (40 F to 70 F) 64MBTU = 65 F Nominal (50 F to 80 F) Models D and U The temperature rise should be as follows: 38MBTU = 52.5 F Nominal (45 F to 60 F) 51MBTU = 55 F Nominal (45 F to 65 F) 64MBTU = 67 F Nominal (60 F to 80 F) In order to calculate CFM use the formula CFM = BTU Output / (1.08 x Temp. Rise) 14

15 Gas Furnace Rollout Switch The flame rollout switch protects the burner area from high temperatures and breaks a circuit back to the DSI Control Board when tripped. The Rollout Switch is located on top of the burner assembly with (2) ¼ screws. The Roll Out Switch is normally closed and opens at 225 F +/- 5 F. This switch must be manually reset and is wired in series with the high limit switch. To prove the roll out switch has failed open, use an ohmmeter and verify there is no continuity across the terminals once the limit has been manually reset from pushing in the red button in between the wire terminals. If the unit is experiencing roll out or constant tripping of the roll out switch check for the following: Cracked or damaged heat exchanger Flame rolling out after the blower motor energizes Clean blue flame becomes erratic and more yellow in color Restricted venter housing or flue Obstructions in the flue pipe or inside the venter housing Note: The furnace and its venting system is designed for proper operation of wind conditions up to 40 mph. Driving winds above 40 mph while operating gas heat may lead to the roll out switch opening. 15

16 Gas Furnace Heat Exchanger The heat exchanger is located on the left side of the furnace. The venter motor pulls fresh air in thru the heat exchanger creating a negative pressure. The burner fires creating combustion gases that heat the heat exchanger, collecting and venting them thru the flue. The blower motor runs and distributes the heat from the heat exchanger thru the ductwork and diffusers. Poor airflow (dirty filters, undersized ductwork), over firing and equipment oversizing can lead to damage of the heat exchanger. *Verify your temperature rise after installing or servicing to ensure long life of the heat exchanger. (see page 14) Heat Exchanger Inspection To view from the top, remove the supply duct and view down into the supply opening. 16 To view from the bottom, remove the chassis (see page 31) for instructions on how to remove) and view up from inside the chassis section of the cabinet. On all U-Serie Models the Heat Exchanger can be easily accessed by following the Slide-Out Furnace Instructions on page 11 & 12.

17 Gas Furnace Pressure Switch The pressure switch is a safety used to prove that the venter motor is running properly and the flue is clear for products of combustion to vent safely WC The Pressure Switch is normally open and closes at 0.55 w.c. To check the pressure switch first prove that the venter motor is pulling the proper static pressure thru the flue. Using a manometer verify it is pulling approximately 1.05 w.c. cold start and.8 w.c. after firing. To prove the pressure switch has shorted closed, use an ohmmeter and verify there is continuity across the terminals when disconnected from the orange tubing. If the unit is experiencing faults with the pressure switch check for the following: Proper venter motor operation with no obstructions in the housing. Inspect the orange tubing for blockages, cracks or other damage. Check the port on the venter housing for blockage with corrosion or debris. Verify that the venter tubing is installed properly on the pressure switch (gray negative side). Look for a restricted flue or venter housing (Mud Wasps nests). 17

18 Gas Furnace Common Causes of Pressure Switch Faults Clear port to venter housing Clear tubing between venter housing and switch Tubing on negative (gray) side of switch 18

19 Gas Furnace Venter (Inducer Draft) Motor The Venter (Inducer Draft) motor is energized with VAC from the DSI control board and is used to pull combustion gases thru the heat exchanger and vent them thru the flue. With a voltmeter verify the proper voltage is present at the motor With and ohmmeter verify that the motor is not shorted to the casing by testing each lead to the motor casing. You should read infinite resistance. With the same ohmmeter verify that the motors windings are not open by reading a closed circuit with approximately 40 ohms of resistance. For simple removal: Remove (3) 5/16" screws to release motor assembly from housing Slide the assembly away to clear the wheel from the housing and remove Note: Place cover over burner opening prior to removing venter screws 19

20 Gas Furnace Flame Sensor Operation Undesired Flame If flame is sensed while the gas valve is de-energized, the control shall energize the venter motor and blower motor on heat speed. When flame is no longer sensed, the venter motor will run through post-purge, and the blower motor will run through the selected heat blower off delay time. The control will do a soft lockout, but will still respond to open limit and flame. The FLAME (yellow) LED shall flash rapidly when lockout is due to undesired flame. Flame Sensor The flame sensor is a safety that proves when a flame is present while the gas valve is open and in operation. The flame sensor is located on top of the burner assembly with (1) 1/4" screw. The Flame Sensor reads the flame from the burner and sends a signal back to the control board via flame rectification. To test the flame sensor use a multi meter capable of reading DC micro amps ( ua ) between Measure between the sensor and the wire from the DSI control board while flame is present. The value should be approximately 3.9 ua. 20

21 Gas Furnace If the unit is experiencing a weak or undesired flame check for the following: Sensor Condition Dirty or corroded No Flame Poor Connection Loose or broken connection on the sensor to the board Broken or cracked porcelain insulator base * Note: The yellow LED on the DSI control board signals if the board is recognizing flame. (see page 23) Gas Valve The gas valve receives a gas supply and regulates gas after a call for heat is initiated. The gas valve is located in the upper right hand section of the furnace assembly. The Gas Valve slowly opens when energized by 24 Volts AC. If the unit is experiencing a spark without ignition check for the following: Gas Valve Power With a voltmeter verify 24 Volts at the gas valve terminals 21

22 Gas Furnace Gas Pressure Check the inlet and outlet gas pressures (Gas pressure can be tested at the inlet and outlet ports on the valve which can be accessed with an allen wrench (be sure to shut the gas supply down while opening the ports). Pressure Requirements Required 3.5 w.c NG outlet (10 w.c. LP) Minimum of 5 w.c.. NG inlet (11 w.c. LP) incoming Maximum of 10 w.c. NG inlet (14 w.c. LP) incoming With the manual valve positioned to prevent flow to the main burner, connect a manometer to the 1/8 pipe outlet pressure tap in the valve. NOTE: A manometer (fluid-field gauge) is recommended rather than a spring type gauge due to the difficulty of maintaining calibration of a spring type gauge. Open the valve and operate the heater. Measure the gas pressure at the outlet of the automatic gas valve. Normally adjustments should not be necessary to the factory-preset regulator. If adjustment is necessary, set pressure to correct settings by turning the regulator screw IN (clockwise) to increase pressure. Turn regulator screws OUT (counterclockwise) to decrease pressure. (If pressures are verified proceed to inspecting the gas line and orifice after the valve.) 22 Gas Valve Relay Fault Gas Valve Relay Fault If the control senses the gas valve as energized for more than one second when the control is not attempting to energize the gas valve, or the gas valve is sensed as not energized when it is supposed to be energized, then the control will lockout with green LED off. The control assumes either the contacts of the relay driving the gas valve have welded shut, or the sensing circuit has failed. The venter motor is forced off to open the pressure switch to stop gas flow unless flame is present. If the gas valve was sensed as closed when it should be open, and has not de-energized after the venter motor was shutoff for 15 seconds, then the venter motor is re-energized to vent the unburned gas.

23 Gas Furnace DSI Control - Ignition Module The DSI Control Module is located in front of the furnace assembly below the gas valve and directly behind the furnace access panel. This control module signals all operations of the CPG including spark ignition. The green and yellow LED s (visible thru the service window) can aid in troubleshooting different failures. DSI Control Troubleshooting CONTROL STATUS STEADY ON FAST FLASH 1 FLASH 2 FLASH 3 FLASH 4 FLASH STEADY OFF DSI INTEGRATED CONTROL MODULE GREEN LED Normal operation, no call for heat Normal operation, call for heat In lockout from failed ignition or flame loss Pressure switch does not close within 30 seconds Limit switch or rollout switch open Pressure switch is closed before venter is energized Internal control fault or no power TIME FAN OFF DELAY DIP SWITCH SETTING SWITCH OFF ON 120 OFF OFF 160 ON OFF 45 ON ON FLAME STATUS STEADY ON SLOW FLASH FAST FLASH YELLOW LED Flame sensed Weak flame (current below 1.0 microamps = +/-50%) Undesired flame (valve open and no call for heat) 23

24 Gas Furnace DSI Control Identification FAN OUTPUT- COOLING FAN OUTPUT- HEATING INPUT INDUCER FAN OUTPUT COOL HEAT HIGH HEAT HEAT LOW EAC/BLO L1 L1 IND NEUTRALS 24VAC, 60Hz.,.5A MAX. ANSI Z21.20 AUTOMATIC CONTROL PLUG SPARK TRANSFORMER B HSCI SPARK IGNITOR OUTPUT TIME MODEL MOLEX TO HEAT COMPONENTS SWITCH 1 OFF OFF ON ON SWITCH 2 ON OFF OFF ON AN1 OK STATUS LIGHTS AN2 FLAME GREEN CONTROL INDICATOR LIGHT (FAULT CODES) FAN OFF DELAY EXTENDED FAN TIME DIP SWITCH SETTING OFF ON SW1 1 2 TEST YELLOW FLAME INDICATOR LIGHT (FLAME ONLY) THERMOSTAT PLUG Y G W R C FUSE P3 MOLEX CONNECTION TO T-STAT WIRE (Y-G-W-R-C) F1 3 AMP COM SEC LOW VOLTAGE COMMON 24V LOW VOLTAGE SECONDARY 24V 3 AMP LOW VOLTAGE FUSE 24

25 Gas Furnace Direct Spark Ignition Electrode The DSI Electrode (Spark Ignitor) is located on top of the burner assembly with (2) 1/4" screws The control board sends a signal which sparks thru to the grounded side of the electrode..74 5/32 If the unit is not sparking or is experiencing a weak spark, check for the following: Ignitor Condition Dirty or cracked porcelain insulator base /16 Spark Gap Gap between ground rod and spark rod should be 1/8".125 ±.015 SPARK GAP Poor Connection Loose or broken connection on the sensor to the board Poor ground connection With an ohmmeter check the continuity between the spark rod and the wire back to the board 25

26 Electric Furnace Components Strip Heaters High Limits Sequencers Contactors Blower Relay Time Delay CPE Control Board Sequence of Operations - Electric Heat, Series A, B, C, D 1. Call for Heat The thermostat sends a call for heat therefore energizing the white wire to the sequencer. The sequencers thermo-disc heats and closes the circuit to the limit switch. If the limit switch is closed the heat strips and blower relay will energize. (on 15KW models the second sequencer will initiate in approximately 90 seconds) 2. Blower Operation The sequencer completes the circuit to the blower relay which energizes and powers the blower motor. The blower will operate until the sequencer contacts break, de-energizing the blower relay. Sequence of Operations - Electric Heat, Series U11 1. Call for Heat The thermostat sends a call for heat therefore energizing the white wire to the 1st contactor. The 2nd contactor (and 3rd if used) will be powered after an adjustable time entry (factory set for 30 seconds) elaspes. 2. Blower Operation At the initial call for heat the blower will energize. The blower will run an extended period after the w are de-energized. 26 Sequence of Operations - Electric Heat, Series U12 (Control Board) 1. Call for Heat When a call for heat is active sending power to the W1 and W2 heating terminals on the control board, the board will begin to sequence the heating outputs to energize the heat contactors. Once W1 is energized the board will sequence output W1A after a 3 second delay and W1B after a 28 second delay. Once W2 is energized the board will sequence out W2 after a 45 second delay.

27 Electric Furnace 2. Blower Operation Once W1, W2, or G is energized the fan will be operated. Once de-energized the fan will run for an additional 5 seconds. CPE Control Board 1. Faults If multiple inputs are received with a cooling input (Y) than the board will automatically fault and run in cooling. 2. Cooling Blower Operation Cooling fan will delay 5 seconds on a call for cooling and will delay off when a call is terminated for the duration of the board jumper set point. (A = 5 sec., B = 30 sec., C = 60 sec., & D = 90 sec.) High Limit The high limit switch protects the strip heaters from overheating due to lack of indoor airflow. This switch breaks a line voltage directly to the heat elements. The High Limit Switch is located on the left side of the electric strip heaters. The High Limit Switch is normally closed, opens at 175 F +/- 5 F with an automatic reset differential of 40 F and is wired in series with the heater element. To prove the high limit switch has failed open, use an ohmmeter and verify there is no continuity across the terminals once the limit has cooled below the differential setting. If the unit is experiencing high limit failures or constant tripping verify your temperature rise (see page 28) and check for the following: Restricted airflow Blocked or dirty air filter Blocked or dirty return air grille Blocked supply duct (closed fire dampers) Blower motor not running (weak capacitor, low voltage) 27

28 Electric Furnace Temperature Rise - Electric AS CLOSE AS POSSIBLE TO THE EVAPORATOR COIL BEHIND THE FILTER DOOR *Example shown has a ducted return In order to calculate CFM use the formula CFM = Voltage x Amperage x / (1.08 x Temp. Rise) APPROXIMATE COLD RESISTANCE 240 volts 2 Banks 20.8 ohms per bank 240 volts 2 Banks ohms per bank 240 volts 2 Banks 10.4 ohms per bank 240 volts 3 Banks 10.4 ohms per bank 28

29 Chassis (Cooling Section) Cooling Chassis The Comfort Packs most serviceable feature is the slide-out cooling chassis. The cooling chassis consists of a complete refrigeration circuit for cooling and gives the ability of removal from the entire comfort pack unit for service and troubleshooting. The integral components of the cooling chassis are as follows, Evaporator Blower Motor Condenser Fan Motor Compressor Evaporator Coil Condenser Coil TXV or Capillary Metering Device Control Deck Compressor Contactor Run Capacitors Transformer Specific Blower Controls Positive Temperature Coefficient Resistors or Hard Start Devices The slide out chassis can be field swapped with another chassis of similar capacity. If a U series chassis is being installed into an older A, B, C, or D series cabinet please make sure a Chassis Conversion Kit is used. (P# ) If the chassis needing service must be pulled completely out and tested on site. Chassis extension plugs may be used to operate the chassis outside but still in front of the cabinet. (P# ) The Chassis can be serviced wherever a 208/230 volt receptacle is available. Using the bench test field wiring harness (P# ), the chassis can be removed and relocated for service then field tested at a remote location. 29

30 Chassis (Cooling Section) The Slide-Out Chassis The slide-out cooling chassis can be easily removed so long that the shipping bolts have been removed prior to installation from both sides of the cabinet. Once removed from the cabinet all components for the cooling section including the blower can be easily serviced. Shipping Bolts located on both sides Shipping Bolts located on both sides 30

31 Chassis (Cooling Section) Chassis Removal Instructions 1. (Not Shown) Remove the bottom filter access panel along with the control access. 2. Remove 4 screws and slide-out air divider panel. 3. Disconnect both power and control power and control molex plugs and drain pipe. 4. Slide chassis forward. Note: Only slide-out chassis out enough to access the blower if you do not plan on completely removing from cabinet. 31

32 Chassis (Cooling Section) Blower Motor Permanent Split Capacitor 1/3 HP 1120 RPM - 3 Speed Used on all R22 Comfort Packs Permanent Split Capacitor 1/4 HP 1075 RPM Single Speed Used on 2 Ton R410A B & C Series Blower clamp needed Permanent Split Capacitor 1/4 HP 850 RPM Single Speed Used on 1 & 1.5 Ton R410A B & C Series 1 Ton units require with Smart Fan Control Blower clamp needed Electronically Commutated 1/3 HP 1120 RPM Multi Speed DC Control Board needed to operate Used on all R410A E and 2.5 Ton C Series Blower clamp needed Electronically Commutated 1/3 HP 1120 RPM 5 Speed No Control Board necessary Used on all D and U Series Blower clamp needed 32

33 Chassis (Cooling Section) Blower Motor Removal Instructions The blower motor can be easily accessed once the chassis is slid out of the cabinet. Follow this procedure on how to easily remove the blower assembly. 1. Remove the 4 screws from the control deck and carefully slide all motor wiring thru the rubber grommet. 33

34 Chassis (Cooling Section) 2. Move aside the control deck and remove the 4 screws that mount the motor housing. 3. Slide the motor assembly up and out of the chassis. Be careful to not damage any refrigeration components while removing the blower assembly. 34

35 Chassis (Cooling Section) PSC Motors Check for proper voltage to the motor. All motors operate at 208/230 Volts AC. Capacitor values for PSC motors MFD MFD MFD PSC Motor with Smart Fan Control The Smart Fan Control is a Triac control board that lowers voltage to the blower motor, controlling the speed of the motor. Fixed speed settings are rated at 80%. Dip Switch settings should be: 1-off 2-off 3-on 4-on 5-off 6-on. The board can be bypassed by removing it from the circuit. 35

36 Chassis (Cooling Section) DC Motor with DC Control Board The DC Control Board takes a 24V input and converts it to a DC Voltage output. Important: DO NOT run the D.C. Motor without the Wheel &/or Fan Blade. 36

37 Chassis (Cooling Section) DC Motor without Board This DC motor requires 208/230 Volts AC and a 24 Volts AC signal to run. The white wire is 24 VAC Common to the motor. The colored wire receives the primary 24 VAC signal in order to run the motor on a specific speed. Make sure the molex is plugged in below the control deck 1- High Red 2- Medium High Yellow 3- Medium Blue 4- Medium Low Black 5- Low Orange 37

38 Chassis (Cooling Section) D & U Series Airflow COMFORT PACK - CFM (w/ Dry Coil) UNIT SIZE COLOR SPEED 0.1 w.c. 0.2 w.c. 0.3 w.c. 0.4 w.c. 0.5 w.c. Red CPG412 Yellow Blue Black Orange X X Red Yellow CPG418 Blue Black Orange X X Red Yellow CPG424 Blue Black Orange X X Red Yellow CPG430 Blue Black Orange X X 38

39 Chassis (Cooling Section) Compressors Reciprocating R22 Reciprocating Compressors required an external discharge muffler. If replacing an older compressor please be aware not to remove without replacing the external discharge muffler. Suction R410 Reciprocating Compressors require a discharge line check valve if replacing the compressor please verify the check valves operation. Discharge Rotary Rotary Compressors come factory assembled with a Suction Accumulator. These compressors also have an external overload device mounted to the top of the compressor. When operating or charging a rotary compressor use extra care and let system pressures equalize prior to starting. If equalization is an issue an electronic hard start device is recommended. (P# ) Discharge Suction Suction Accumulator 39

40 Chassis (Cooling Section) Scroll Scroll compressors can be susceptible to high temperatures. High temperature oil can break down and damage the seals and scrolls internal to the compressor. Discharge line temperatures taken 6 inches away from the compressor must be below 225 F in order to keep the compressor temperature below 300 F. Oil loses its lubricity above 300 F and starts to break down at 350 F. Discharge Suction Recommended superheat taken at the compressor suction line 6 inches from the compressor is 20 F. Positive Temperature Coefficient Resistors (PTCR) PTCR s may be found in use with Rotary or Reciprocating Compressors. When starting the compressor the PTCR at a low resistance provides current to the start winding of the compressor. After time delay the current that moves thru the PTCR causes it to heat and switch to a very high resistance. As long as voltage remains on the circuit (like it would when the compressor contactor is energized), the PTCR remains switched into this very high resistance and the run capacitor operates the compressor. When the voltage is removed from the PTCR the current switches back to a low resistance and the PTCR begins to cool. It is important to give the PTCR enough time to cool in the off voltage, low resistance mode (approximately 3 to 5 minutes). The PTCR can be tested by reading the resistance across the terminals while disconnected. The PTCR should read 35 Ohms +/- 30%. 40

41 Chassis (Cooling Section) IMPORTANT!!! BEFORE REMOVING A WARRANTY COMPRESSOR, PLEASE FILL OUT THE FOLLOWING AND CALL (800) REMOVAL OF COMPRESSOR WITHOUT FACTORY VERIFICATION CAN LEAD TO WARRANTY CREDIT BEING DENIED 1. Incoming Voltage to Compressor at Contactor is: Volts AC 2. Compressor Starting AMP Draw: R 3. Compressor Winding OHM Reading between Terminals C & S: Ω 4. Compressor Winding OHM Reading between Terminals C & R: Ω 5. Compressor Winding OHM Reading between Terminals R & S: Ω 6. Compressor Winding OHM Reading between Terminals C & Ground: Ω 7. Compressor Winding OHM Reading between Terminals R & Ground: Ω 8. Compressor Winding OHM Reading between Terminals S & Ground: Ω 9. Run Capacitor Reading from HERM to COM: Start Capacitor Reading if Used: uf + uf TOP VIEW OF CAPACITOR 11. If the Compressor is Operating Please Indicate the Following: Suction Pressure: psig Discharge Pressure: psig Super Heat: F Subcooling: F C HERM FAN 41

42 Chassis (Cooling Section) Thermal Expansion Valve (TXV) The TXV is located underneath the control deck. The TXV meters refrigerant based on pressures in the system and temperatures at the bulb location. The spring tension plus the evaporator pressure (which is measured thru the external equalizer tube) counter the pressure in the power element. As the bulb becomes warmer it increased the pressure in the diaphragm of the power element thus opening the valve. As the evaporator pressure increases and/or the bulb temperature decreases the valve will begin to close. Example The bulb temperature at the outlet of the evaporator is 55 F which equals 155 psig of diaphragm pressure. The evaporator pressure taken from the external equalizer line at the outlet of the evaporator is 110 psig. This added to the spring tension of 25 psig equals a total of 135 psig. The 155 psig diaphragm pressure is greater than the 135 psig combined spring and evaporator pressure so the valve will begin feeding refrigerant. The TXV Bulb (attached to its power element) must be securely fastened and firmly insulated to the suction line as shown below. TXV LOCATED UNDER CONTROL DECK Distributor BULB SECURED TIGHTLY TO SUCTION LINE BULB INSULATED FIRMLY IDEAL LOCATION FOR CHECKING SUPER HEAT 42 If you are experiencing system pump down, inspect external equalizer tubing for restriction.

43 Chassis (Cooling Section) Refrigeration Service Easy service port access is available on the right hand side of the chassis above the control deck. Use these ports to verify system operating pressures along with superheat and subcooling for proper refrigeration system diagnosis. Note Comfort Pack service ports use Coremax fittings. A Coremax removal tool is required to remove the coremax fitting while under pressure. Use of a standard schraeder removal tool will damage the coremax valves. INSULATION LIQUID SUCTION IDEAL LOCATION FOR CHECKING SUPER HEAT R410A Superheat 8-12, Subcooling SUCTION PRESSURE DISCHARGE PRESSURE SUPER HEAT LOW LOW LOW SUBCOOLING LOW LOW HIGH LOW POSSIBLE CONDITION INSUFFICIENT AIR FLOW ACROSS EVAPORATOR COIL INSUFFICIENT REFRIGERANT CHARGE / LOW SIDE RESTRICTION LOW HIGH HIGH HIGH HIGH SIDE RESTRICTION HIGH HIGH LOW HIGH HIGH HIGH LOW HIGH EXCESSIVE LOADING ON EVAPORATOR COIL INSUFFICIENT AIR FLOW ACROSS CON- DENSER COIL HIGH HIGH LOW HIGH EXCESSIVE REFRIGERANT CHARGE HIGH HIGH VARYING HIGH AIR OR NON CONDENSABLE IN SYSTEM HIGH LOW OVERFEEDING METERING DEVICE HIGH LOW DEFECTIVE VALVES IN COMPRESSOR 43

44 Chassis (Cooling Section) Compressor Contactor The compressor contactor is used to send line voltage to the compressor and condenser fan motor. SINGLE SWITCHING POLE BUSS CONNECTIO N The 24 volt coil is powered by a call for cooling and wired in series with the low pressure switch. 24 Volt COIL CONNECTION * IF THE CONTACTOR HAS BEEN REPLACED WITH A 2 SWITCHING POLE CONTACTOR VERIFY PLACEMENT OF POWER LEG TO THE BLOWER MOTOR TO ENSURE PROPER OPERATION IN HEATING MODE Low Pressure Switch 50 psi +/- 5 psi 70 psi +/- 5 psi The low pressure switch located on the chassis is a safety feature to keep the compressor from operating at pressures lower then recommended. The pressure switch is molded and sealed into the refrigeration circuit. The switch breaks the call for cooling from Y to the contactor coil. 40VA Transformer The transformer is used to supply low voltage to the Comfort Pack control circuit. Its Primary side must be supplied with 208/240 VAC. Its secondary side supplies 24 VAC. Failure to adjust the transformer in 208 volt applications will then change low voltage output and can affect low voltage components in the unit. O LINE VOLTAGE INPUT (FACTORY SET FOR 240V) MUST BE FIELD ADJUSTED FOR PROPER LOW VOLTAGE OUTPUT LOW VOLTAGE OUTPUT 44

45 Chassis (Cooling Section) Drainage Drain Pan SECONDARY DRAIN TRAP MUST BE INSTALLED 3/4 O.D. Drain Connection (Primary Drain) 3/4 I.D. Flexible Tubing Included 2 min. Highest Point Must Not Be Above Bottom of Drain Pan Pitch Downward 1 per 10ft. Shaded Area Represents Components Provided and Installed By Others A drain pan is positioned underneath the evaporator coil to collect condensate. A ¾ flexible tube included with the unit should be connected to the drain connection on the drain pan so it can be easily disconnected for chassis removal. A 2 deep trap should be installed close to the pan. Secondary Drainage The secondary drain is an option that offers protection from overflow. The secondary drain feature is piped into the base of the unit and drains through the weep holes outside. Drain Pan Secondary Drain Connection 1/2 I.D. Tubing Grommet Chassis Base Squeeze Trap 45

46 Find Out the Age of a Unit Serial Number Code Find Out the Age of a Unit CURRENT (Effective 01/01/2003 to Current Day) Position 1: Product Line 2 =NCP & Comfort Pack prior to After 01/01/ was used to indicate Comfort Pack. Position 2 & 3: 42=2002, 43=2003, 44=2004, 45=2005, 46=2006, 47=2007, 48=2008, 49=2009, 50=2010, 51=2011, 52=2012, 53=2013, 54=2014 Position 4: Position 5-8: Month 1=Jan, 2=Feb, 3=Mar, 4=April, 5=May, 6=June, 7=July, 8=Aug, 9=Sept, A=Oct, B=Nov, C=Dec Sequence number (resets the first of each month) Comfort Pack: (5 Year Warranty On Parts, 5 Year Warranty on Compressor, 10 year on Heat Exchanger) 46

47 Wiring Diagrams Comfort Pack Gas A - Series R22 47

48 Wiring Diagrams Comfort Pack Gas B - Series R22 48

49 Wiring Diagrams Comfort Pack Gas B - Series R410A 49

50 Wiring Diagrams Comfort Pack Gas C - Series R410A 50

51 Wiring Diagrams Comfort Pack Gas D - Series R410A 51

52 Wiring Diagrams Comfort Pack Gas E - Series R410A 52

53 Wiring Diagrams Comfort Pack Gas U11 - Series 53

54 Wiring Diagrams Comfort Pack Gas U12 - Series REVISION 3 54

55 Wiring Diagrams Comfort Pack Electric U12 - Series, 5, 7, 10 KW Revison 1 55

56 Wiring Diagrams Comfort Pack Electric U12 - Series, 15 KW Revison 1 56 Call factory for information on other models.

57 Index A Abnormal Functions 9 B Blower Delay 8 Blower Motor 32 Blower Motor Removal 33, 34 Blower Off Delay 9 C Call for Heat 8 Chassis 29 Chassis Removal 31 Compressor Contactor 44 Compressors 39 Contactor 44 Control Board (Main) 24, 25 Cooling Chassis 30 Coremax fittings 45 D DC Motor 38 DC Motor (without board) 37 DC Motor Board 36, 37 Dimensions 4 Door Switch 5 Drainage 45 DSI Control 23, 24, DSI Electrode 25 E Electric Furnace 26 F Flame Sensor 20, 21 Furnace 5 Furnace Specification 5 G Gas Furnace 5 Gas Pressure 22 Gas Valve 21 Gas Valve Relay Fault 22 H Hard Lockout 9 Heat Exchanger 16 Heat Exchanger Inspection 16 High Limit Switch 13 High Limit Switch (Electric Heat) 27 I Ignition Module 23, 24, 25 Ignition Retry 9 Ignition Trial 8 Inducer Draft Motor 19 Interlock Door Switch 5 Interrupted Thermostat Call for Heat 9 L Limit Switches 10 Lockouts 9 Low Pressure Switch 44 M Model Number Identification 3 P Post-purge 8 Power Interruption 9 Pre-purge 8 Pressure Switch 17 PSC Motors 35 R Refrigeration 43 Rollout Switch 10, 15 S Safety Switches 10 Secondary Drain 45 Sequence of Operations (Electric) 26 Sequence of Operations (Gas) 8 Serial Number Identification 46 Service Ports 43 Smart Fan Control 35 Soft Lockout 9 Spark Ignitor 25 Steady Heat 8 T Temperature Rise (Electric) 28 Temperature Rise (Gas) 14 Transformer 44 Triac Board 35 TXV (Thermal Expansion Valve) 42 V Venter Motor 19 W Wiring Diagrams 47 57

58 Technical Support For Technical Support: Phone:

59 Notes 59

60 NATIONAL COMFORT PRODUCTS HEATING & A/C EQUIPMENT National Comfort Products A Division of National Refrigeration and Air Conditioning Products, Inc. 539 Dunksferry Road Bensalem, PA (800) Fax (215) Service Guide Comfort Pack 05/2017