Summary of the content on the page No. 1 
                    
                         
 
GAS FIRED HIGH EFFICIENCY FURNACE 
DOWNFLOW & DIRECT VENT (SEALED COMBUSTION) 
 
MODELS: 
CMA3-50D36N, CMA3-75D36N, 
CMC1-50D36N, CMC1-75D36N, 
CMC1-50DV3N, CMC1-75DV3N 
INSTALLATION AND SERVICE MANUAL 
For installation in:  
1. Manufactured Homes 
2. Modular Homes/Buildings 
3. Site Constructed—Residential (Single Story Dwellings) 
  
 
 
FOR YOUR SAFETY 
Do not store or use gasoline or other flammable vapors and liquids in the vicinity of this or 
any other appliance.  
WHAT TO DO IF YOU S
                    
                    Summary of the content on the page No. 2 
                    
                                       TABLE OF CONTENTS    SECTION         BEGINNING PAGE  I. SAFETY INFORMATION        1    II. FURNACE SPECIFICATIONS        7    III. GENERAL INSTRUCTIONS AND CLEARANCES     11    IV.  GENERAL INSTALLATION        13   A.  FURNACE LOCATION        13   B.  BASE INSTALLATION        15   C.  ALCOVE INSTALLATION        16   D.  CLOSET INSTALLATION        14   E.  FUEL PIPING         19   F.  GENERAL VENTING REQUIREMENTS      20   G.  CONNECTING THE EXHAUST VENT, AND COMBUSTION    22      
                    
                    Summary of the content on the page No. 3 
                    
                        All installations and services must be performed by qualified service personnel.  I.  SAFETY INFORMATION    This and the following page contain reproductions of the various warning and instruction  labels placed on the Thermo Pride Condensing Gas Furnaces. Please read and comply  with the contents of these labels.     1                                                                                                                                                                                   
                    
                    Summary of the content on the page No. 4 
                    
                        All installations and services must be performed by qualified service personnel.  This and the previous page contain reproductions of the various safety and instruction  labels placed on the Thermo Pride Condensing Gas Furnaces. Please read and comply  with the contents of these labels.         2                                                                                                                                                                                                           
                    
                    Summary of the content on the page No. 5 
                    
                        All installations and services must be performed by qualified service personnel.  This and the previous page contain reproductions of the various safety and instruction  labels placed on the Thermo Pride Condensing Gas Furnaces. Please read and comply  with the contents of these labels.   3                                                                                                                                                                                                                 
                    
                    Summary of the content on the page No. 6 
                    
                        All installations and services must be performed by qualified service personnel.  The following safety information should be read, understood, and followed by the  installer.    1. Use only with type of gas approved for this furnace.  Refer to furnace rating plate.    2. Do not install this furnace where it could be exposed to drafts or other wind or  moisture conditions.  Refer to Section IV of this manual.    3. Provide adequate ventilation air to the furnace space. Refer to Section IV, C and 
                    
                    Summary of the content on the page No. 7 
                    
                        All installations and services must be performed by qualified service personnel.  : The vent and air intake elbows must be kept away from bushes,  shrubs or any vegetation that may restrict the flow of flue products. It must also  be kept clear of any leaves, weeds or other combustible materials. Keep the vent  hood clear of snow. Avoid locating the terminals in areas where standing water or  condensate drippage may be a problem.    : This CMA/CMC furnace has been designed to be installed as a d
                    
                    Summary of the content on the page No. 8 
                    
                        All installations and services must be performed by qualified service personnel.  : Copper and brass tubing and fittings (except tin lined) shall not be  used if the gas contains more than a trace (0.3 grains per 100 cubic ft.) of  hydrogen sulfide gas. Check with your gas supplier.    : TURN OFF THE ELECTRICAL POWER to the furnace before attempting  to change blower speed wiring.    : Turn off power to furnace before it is placed into service. The gas  piping system must have been leak tested b
                    
                    Summary of the content on the page No. 9 
                    
                        All installations and services must be performed by qualified service personnel.  II.  FURNACE SPECIFICATIONS  MODEL CMA3-50D36 CMA3-75D36             INPUT IN BTUH 50,000 75,000     OUTPUT IN BTUH 48,000 72,000     MAIN ORIFICE-NAT. #42    MAIN ORIFICE-LP #54    GAS SUPPLY PRESSURE         L.P. MINIMUM                                                11” IN.W.C.  NAT. MINIMUM                                              4.5”IN.W.C.  L.P. MAXIMUM  14” IN.W.C.    NAT. MAXIMUM   14” IN.W.C.    GAS M
                    
                    Summary of the content on the page No. 10 
                    
                        All installations and services must be performed by qualified service personnel.  MODEL CMC1-50D36 CMC1-75D36              INPUT IN BTUH 50,000 75,000     OUTPUT IN BTUH 48,000 72,000     MAIN ORIFICE-NAT. #42    MAIN ORIFICE-LP #54    GAS SUPPLY PRESSURE         L.P. MINIMUM                                                11” IN.W.C.  NAT. MINIMUM                                              4.5”IN.W.C.  L.P. MAXIMUM  14” IN.W.C.    NAT. MAXIMUM   14” IN.W.C.    GAS MANIFOLD PRESSURE         L.P
                    
                    Summary of the content on the page No. 11 
                    
                        All installations and services must be performed by qualified service personnel.  MODEL CMC1-50DV3 CMC1-75DV3              INPUT IN BTUH 50,000 75,000     OUTPUT IN BTUH 48,000 72,000     MAIN ORIFICE-NAT. #42    MAIN ORIFICE-LP #54    GAS SUPPLY PRESSURE         L.P. MINIMUM                                                11” IN.W.C.  NAT. MINIMUM                                              4.5”IN.W.C.  L.P. MAXIMUM  14” IN.W.C.    NAT. MAXIMUM   14” IN.W.C.    GAS MANIFOLD PRESSURE         L.P
                    
                    Summary of the content on the page No. 12 
                    
                        All installations and services must be performed by qualified service personnel.  INSTALLATION PARTS PACKAGES      CMA3-50D36N CMA3-75D36N                           PARTS PKG#      S00S4248 S00S4249  DESCRIPTION  PART # QTY PART # QTY  J-box cover 350020 1 350020 1  Wire nut 300132 2 300132 2  3" stainless steel hose clamp 300276 4 300276 4  2-3/8" radiator hose 410017 2 410017 2  CPVC adapter 320833 1 320833 1  LP conversion kit AOPS7741 1 AOPS7742 1      CMC1-50D36N CMC1-75D36N                
                    
                    Summary of the content on the page No. 13 
                    
                        All installations and services must be performed by qualified service personnel.  III.  GENERAL INSTRUCTIONS AND CLEARANCES – READ BEFORE START OF   INSTALLATION    1.  The BTU output capacity of the furnace proposed for installation should be based  on a heat loss calculation made according to the manuals provided by the Air  Conditioning Contractors of America (ACCA) or the American Society of Heating,  Refrigeration and Air Conditioning Engineers, Inc. (ASHRAE).    2.  This furnace is equippe
                    
                    Summary of the content on the page No. 14 
                    
                        All installations and services must be performed by qualified service personnel.  d. American National Standard (ANSI-C1/NFPA-70 Electric Code for all  electrical field wiring.  e. These gas-fired units have been investigated under standards ANSI Z 21.47  CAN/CGA Z223-2001 Central Furnace test standards.  f. These gas-fired units have been listed by ETL “For installation as central  furnace special type for single story dwelling.”      : The area around the furnace must be kept free and clear of
                    
                    Summary of the content on the page No. 15 
                    
                        All installations and services must be performed by qualified service personnel.  IV. GENERAL INSTALLATION     A.  FURNACE LOCATION    1.  For best performance, locate the furnace so that it is centralized with respect  to the duct system.    2.  The furnace installation is only intended for free air return through the furnace  door louvers. DO NOT connect a ducted return air system directly to the furnace.  An improper return air installation may create a hazard and damage equipment,  as well a
                    
                    Summary of the content on the page No. 16 
                    
                        All installations and services must be performed by qualified service personnel.  Coil Cabinet Model: CE113S / CE213T         Note: Coil cabinet cannot be utilized as a cottage base.    CE113S          CE213T   Figure 1B.         Cottage Base Model: 01COT-BASE  For CMA3 models only.   NOTE:  Serves as a plenum for single story applications with exposed supply air  systems.                                Figure 1C.       14                                                                          
                    
                    Summary of the content on the page No. 17 
                    
                        All installations and services must be performed by qualified service personnel.  B.  BASE INSTALLATION – CMA3 models only     1. Combustible Floor Base Model: 70 BASE (for CMA3 models only)    Use the base bottom panel as a template to mark floor opening locations (see  Figure 2). Cut a square opening in the floor for the supply air connector duct. Cut  the opening 1-inch larger than the square template opening. (duct requires 1-inch  clearance to combustible floor).                            
                    
                    Summary of the content on the page No. 18 
                    
                        All installations and services must be performed by qualified service personnel.  connector duct. Remove the bottom panel. Cut an opening in the distribution duct  slightly larger than the connector duct. (refer to Figure 2 for location of this cut.)  Cut the connector duct to length. Install the connector duct. Bend over each tab.  Insure an airtight seal by using high temperature sealant or tape on the joint.  Reinstall the bottom panel over the connector duct. Put the base top assembly in  pl
                    
                    Summary of the content on the page No. 19 
                    
                        All installations and services must be performed by qualified service personnel.  C.  ALCOVE INSTALLATION    In this application, a minimum of 18 inches of clearance must be provided to the  front of the unit. See Figure 4.    Note – access to diagnostic view port.    CMA3 SERIES        CMC1 SERIES   Figure 4.        D.  CLOSET INSTALLATION     1.  The return air opening into the closet  is to have a minimum free area of 250   sq. in. (see Figure 5).    2.  The return air opening may be located 
                    
                    Summary of the content on the page No. 20 
                    
                        All installations and services must be performed by qualified service personnel.  CMA3 SERIES        CMC1 SERIES  Figure 5.    :  Do not obstruct any return air openings, including the return  grille on the furnace. To do so may cause the furnace to activate the high  limit and shut down.     3.  The cross-sectional area of the return system leading into the closet (when  located in the floor or ceiling) shall not be less than 250 square inches.    4.  The total free area of openings in the floo