Nordyne M4RC-072D-35C, Installation Instructions Manual

20

Table 4

1 Pipe Installations

Vent

Upflow

Downflow

Up

Option 1

Option 7

Right

Option 2*

Option 8*

Left

Option 3*

Option 9*

2-Pipe Installations

Vent

Upflow

Downflow

Up

Option 4

Option 10

Right

Option 5*

Option 11*

Left

Option 6*

Option 12*

Table 4. 

Vent & Inducer Blower Options

 CAUTION:

It  is  good  practice  to  label  all  wires  prior 

to disconnection. Wiring errors can cause 

improper and dangerous operation.

1. Disconnect the electrical harness from the inducer 

assembly.

2. Remove the inducer assembly ground wire from the 

blower deck.

3. Remove three screws securing the inducer assembly 

to the header box.

4. Rotate the inducer assembly to its new position.
5. Secure the inducer assembly to the header box by 

reinstalling the three screws. If the inducer assembly 
is rotated to the left or right side of the furnace, use the 
extra screw provided in the parts package.

6. Remove the cabinet plug from side of furnace and 

reinstall in hole on opposite side of cabinet. NOTE: The 
cabinet plug must always be used to close the hole in 
the side of the furnace when rotating the inducer.

7. Install in-line drain assembly and tubing.
8. If applicable, install the condensate drain lines For M4RC 

series see 

Figure 44

. For M4RL series see 

Figure 45

.

9. Reconnect the electrical harness to the inducer 

assembly.

10. Reconnect the inducer assembly ground wire to the 

blower deck or door.

11. Verify operation as detailed on the furnace label.

Pressure Switch Tubing

Figure 24 (page 21)

 & 

Figure 25 (page 21)

 display 

the proper routing of pressure switch tubing for *M4 
Series furnaces. All upflow (M4RC)  furnaces have two 
switches, one connected to the static tap on the inducer 
assembly and the other to the collector box. Downflow 
(M4RL Series) furnaces require only one switch connected 
to the inducer’s static tap as shown in 

Figure 25

.

Figure 23

Figure 23. 

Alternate Removal Method

1

4

2

7

3

6

5

Inducer & Venting Options

To increase installation flexibility, the inducer assembly can 
be rotated up to 3 different positions. Each variation has 
slightly different requirements with regard to condensate 
disposal and, in some cases, the need to seal the furnace 
cabinet.

1. Prior to vent installation, determine the number of pipes 

to be connected to the furnace (1-pipe or 2-pipe), the 
airflow of the furnace (upflow or downflow), and then 
the side that the pipes will exit from the furnace.

2. Select the option from 

Table 4

 that properly matches 

your installation type and then find your setup (by Option 
number) in 

Figure 44 (page 44)

 & 

Figure 45 (page 

45)

.

It is important that Direct Vent (2-pipe) systems maintain 
an airtight flow path from the air inlet to the flue gas outlet. 
The furnace ships from the factory with two holes in the 
cabinet for the air inlet and flue gas outlet. In certain 
configurations, it is necessary to remove and relocate 
a plastic cap in the furnace cabinet. If changing the 
position of the air inlet and flue gas outlet, it is required 
that the previous hole be closed off with the plastic cap 
to maintain air tightness in the furnace. Measurements 
for hole locations on *RC and *RL series furnaces are 
shown in 

Figure 41 (page 37)

.

Inducer Assembly Rotation

 WARNING:

Inducer  rotation  must  be  completed  before 

the furnace is connected to gas and electric. If 

both utilities have been connected, follow the 

shutdown procedures printed on the furnace 

label and disconnect the electrical supply.