Contents
INSTALLATION AND OPERATION MANUAL
MODELS FOR USE WITH NATURAL GAS OR LP GAS PROPANE
CHX3-75N CDX3-75N CHX3-100N CDX3-100N
CHX3-125N 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
SECTION
INDEX
BEGINNING PAGE
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 LOCATION
Figure
PVC Pipe Designation
Maximum Quantity of Elbows
Outside Combustion Air Intake RH view
E.Direct Venting Through a Sidewall
c.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
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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 ASSEMBLY
Figure 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
Figure
K. FILTERS 1. CHX3 MODELS: HIGHBOYS
2. CDX3 MODELS: COUNTERFLOWS
Figure
L. WIRING
Table 4A
Time
S7 DIP Switch
Switch Settings
Options
2-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 UP
B.Gas flowrate by clocking gas meter
C. Measuring And Adjusting Heat Input Rate
Observe the following precautions when measuring
A.Burner manifold pressure with a pressure gauge
NOTICE: 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 below
Checkout Procedure
TABLE 6 - CONVERTING GAS FLOW RATE
V. INSTALLERS INSTRUCTIONS TO USER
D. FURNACE CHECKOUT PROCEDURE
Figure VI. TROUBLESHOOTING
Power must be disconnected before servicing
DIAGNOSTIC FEATURES
TROUBLESHOOTING 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
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Appendix – B Wiring Diagrams
