Thermo Products 125n, chx-3 75n, 100n operation manual StageBlower Settings from factory C

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

Modifications to ECM blower speed settings are done using the S3 and S4 dip switch controls. Thermo Pride two-stage furnaces are factory shipped at the CFM settings listed below in Table 4C.

2-Stage Blower Settings (from factory)

Table 4C

	Unit	Control Board	Heating	Heating	Constant Fan	Cooling
		Dip Switch	CFM	CFM	Constant Fan	Cooling
		Dip Switch	CFM	CFM	CFM	CFM
		Settings	(low fire)	(high fire)	CFM	CFM
		Settings	(low fire)	(high fire)
		SW3 1-4 Off
	CDX3-75	SW4 1-3 Off	885	1012	500	1000
		SW4 4 On
	CHX3-75	SW3 1-4 Off	760	931	500	1000
	CHX3-75	SW4 1-4 Off	760	931	500	1000
		SW4 1-4 Off

		SW3 1-4 Off
	CDX3-100	SW4 1-3 Off	1094	1340	600	1200
		SW4 4 On
	CHX3-100	SW3 1-4 Off	1015	1243	600	1200
	CHX3-100	SW4 1-4 Off	1015	1243	600	1200
		SW4 1-4 Off

		SW3 1-4 Off
	CDX3-125	SW4 1-3 Off	1366	1673	700	1400
		SW4 4 On
	CHX3-125	SW3 1-4 Off	1270	1556	700	1400
	CHX3-125	SW4 1-4 Off	1270	1556	700	1400
		SW4 1-4 Off

For adjustments to the Cooling CFM settings, as well as all additional CFM changes, please reference the dip switch tables listed in the ECM operation manual. (Included with every furnace.)

5.DE-HUMIDIFICATION

The ECM motor in conjunction with the W/R 50V51-843 has a feature to enhance de-humidification in the cooling mode. In the dehumidify mode the indoor blower motor (ECM) reduces CFM. By reducing airflow the indoor coil runs colder and thus extracts more moisture from the air.

The W/R 50V51-843 is shipped from the factory with dipswitch S5-2 set to on for system that do not have a dehumidification connection from the thermostat. For systems using a thermostat that provides dehumidification option move dip switch S5-2 to “OFF”. With the S5-2 switch in the “OFF” position the air conditioning fan speed will be reduced 30% from the normal CFM setting when the humidity in the home is higher than the set point of the dehumidistat.

6.FIELD WIRING AND REPLACING WIRING

Field wiring between the furnace and devices not attached to the furnace shall conform with the temperature limitation for Type T wire[63°F rise (35°C)] when installed in accordance with the manufacturer’s instructions. If any of the original factory supplied furnace wiring is replaced or a separate device other than the thermostat is wired internal to the unit 105°C thermoplastic or equivalent wire must be used.

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Contents CHX3-75N CDX3-75N CHX3-100N CDX3-100N MODELS FOR USE WITH NATURAL GAS OR LP GAS PROPANECHX3-125N CDX3-125N INSTALLATION AND OPERATION MANUALI. 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 CDX3 SERIES INSTALLATION PARTS PACKAGES – CHX3-75 INSTALLATION PARTS PACKAGES – CDX3-75 Grounding instructions III. GENERAL INSTALLATION B1. CDX3 HORIZONTAL APPLICATION B. FURNACE LOCATIONFigure 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 •near soffit vents, crawl space vents, or other areas where condensate or water vapor could create a nuisance, hazard, or cause property damage, and 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 Applications Applications leading away from the furnace must be composed of 3-inchdiameter PVC pipe and pipe fittings only. Refer to item E in Figure 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: HIGHBOYSFigure Figure L. WIRING Table 4A Switch Settings S7 DIP SwitchOptions Time2-StageBlower Settings from factory Table 4C IV. STARTING THE UNIT A. SEQUENCE OF OPERATIONS FLAME MUST BE DETECTED 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 = Figure 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 CHECK FOR 24 VOLTS Appendix –AReplacement Parts List Page Page Page Appendix – B Wiring Diagrams