Thermo Products CDX3-100N, CDX3-75N, CHX3-75N, CHX3-125N, CDX3-125N Figure VI. TROUBLESHOOTING

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All installations and services must be performed by qualified service personnel.

5.That failure to maintain and operate this furnace in accordance with these instructions could result in hazardous conditions, bodily injury, property damage and may void the limited warranty on the furnace.

6.Review with and encourage the user to read the label reproductions and all warnings and instructions outlined on the front cover and in sections I, II and III of this manual and in the Users Information Manual.

7.Recommend that the user have a qualified heating contractor inspect the furnace at the start of each heating season. Inform the user of the frequency of inspection required for reach item in Section III of the Users Manual.

Figure 25

VI. TROUBLESHOOTING

NOTICE: BEFORE TROUBLESHOOTING, FAMILIARIZE YOURSELF WITH THE START UP AND CHECKOUT PROCEDURE.

ALL INSTALLATION AND SERVICES MUST BE PERFORMED BY QUALIFIED HEATING CONTRACTORS.

To assist you in troubleshooting this furnace, it is equipped with an integrated ignition control with diagnostics. These diagnostics evaluate what control system has experienced a failure and will activate a flashing light on the control in different sequences to help pinpoint the failure which has occurred.

For your convenience, Thermo Products has installed a sight glass in the blower door of this furnace. The number of flashes in groups should be observed through this sight glass and recorded before turning off power to the furnace. Turning off power to the furnace or removing the blower door which is equipped with a door interlock switch will reset the control. Should this occur, use the fault code retrieval process as described below.

To retrieve fault codes, push and release the “LAST ERROR” button for more than 1/5 second and less than 5 seconds. (Control will indicate this period by solid GREEN for 1/5 second to 5 seconds.) The LED will flash up to five stored fault codes, beginning with the most recent. If there are no fault codes in

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Contents TWO STAGE CONDENSING GAS FURNACE MODELSOR LP GAS PROPANE CDX3-75N CDX3-100N CDX3-125N I. SAFETY INFORMATION This and the previous page contain reproductions of the various warning and instruction labels placed on the Thermo Pride Two Stage Condensing Gas Furnaces. Please read and comply with the contents of these labels 1.A windows be opened The CHX3/CDX3 furnace models are sealed combustion design, which does not require an air shutter adjustment air shutters are not used for proper flame characteristics. Burner box access cover must always be secured with all screws in place and tightened before operating furnace BEGINNING PAGE INDEXSECTION II. FURNACE SPECIFICATIONS CHX3 SERIES CDX3 SERIES INSTALLATION PARTS PACKAGES - CHX3-75 INSTALLATION PARTS PACKAGES - CDX3-75 Grounding instructions III. GENERAL INSTALLATION B1. CDX3 HORIZONTAL APPLICATION B. FURNACE LOCATIONPage PVC Pipe Designation Maximum Quantity of Elbows Outside Combustion Air Intake RH view E.Direct Venting Through a Sidewallc.The vent terminal shall not be located Page E1. Single-PipeSidewall Venting Option 5.Optional Direct Vent Terminations Install these optional kits according to the instructions provided with each kit. The location and clearance requirements are identical to those of the standard vent terminations described in this manual 1.Figures 6B, 7, and 8 follow depicting typical exhaust vent and air intake connections for the furnace model series CHX3 and the CDX3, respectively, as well as a list of required parts to correctly install each system Page Applications Furnace Model Series CHX3 Figure 9 Typical Internal VentPiping Arrangement for the 3. Connecting The Combustion Air Intake Piping Figure 14. TRAP ASSEMBLY MOUNTED ON CHX3 I.CONDENSATE DRAIN LINE AND TRAP ASSEMBLYFigure 15. TRAP ASSEMBLY MOUNTED ON CDX3 2.Determine on which side of furnace the condensate disposal line is to be run NOTICE On CHX3/CDX3’s this must be the same side as the flue outlet or bottom of unit. Attach the condensate trap to the furnace casing using the #8x3/4” sheet metal screws provided in the parts package. Pilot holes are provided on both sides of the casing for mounting J. GENERAL GAS PIPING J1. REQUIREMENTS AND SIZING OF DUCT WORK Figure 18A TABLE 2A 2. CDX3 MODELS COUNTERFLOWS K. FILTERS 1. CHX3 MODELS HIGHBOYSPage L. WIRING Table 4A Switch Settings S7 DIP SwitchOptions Time2-StageBlower Settings from factory Table 4C IV. STARTING THE UNIT A. SEQUENCE OF OPERATIONS IF NOT IF THERMOSTAT W2 CONTACTS ARE CLOSED OTHERWISE OPERATING INSTRUCTIONS B. INITIAL START UPObserve the following precautions when measuring C. Measuring And Adjusting Heat Input RateA.Burner manifold pressure with a pressure gauge B.Gas flowrate by clocking gas meterNOTICE A U-tubemanometer, measuring pressure in inches of water column, is recommended for all gas pressure measurements. However, an aneroid pressure gauge, in good working condition, capable of reading pressure changes of 0.05 in. W.G., or less, that was recently calibrated within the last year, is a satisfactory alternate. These two 2 devices will be considered as equivalent and interchangeable. Either device is referred to below as a “pressure gauge” Heat input rate in BTUH = Page Checking The Burner Flame 21.Go to Checkout Procedure belowCheckout Procedure TABLE 6 - CONVERTING GAS FLOW RATE V. INSTALLERS INSTRUCTIONS TO USER D. FURNACE CHECKOUT PROCEDUREFigure VI. TROUBLESHOOTING Power must be disconnected before servicing DIAGNOSTIC FEATURESTROUBLESHOOTING GUIDE IS INDUCER RUNNING ON LOW SPEED? YES DOES THE HOT DO BURNERS STAY LIT PAST PROOF OF FLAME CHECK? REPLACE THE 50V51-843CONTROL DOESBURNERSHUT OFF Appendix -AReplacement Parts List Page Page Page Appendix - B Wiring Diagrams