Pressure Tubing Removal / Replacement - A.O. Smith 12 40GPC T 100 Service Handbook

Standard residential high efficiency atmospheric vent (fvir) gas water heaters

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Table Of Contents

Table of Contents

Important: Use only factory authorized replacement

parts. If you lack the necessary skills to properly

perform the installation, you should not proceed, but

get help from a qualified service technician.

Tools required: Phillips Head Screwdriver.

Removing the Air Intake Chamber Box:

1. Set the gas control valve/thermostat to its lowest

setting by pressing the "COOLER" and "HOTTER"

buttons together at the same time holding for 1

second. Then press the "COOLER" button to the

lowest setting (Figure 74).

2. Turn gas control switch to the "OFF" position

(located right side of the gas control valve/

thermostat) and turn off the gas supply to the unit

(Figure 75).

3. Disconnect the electric connection by unplugging

the transformer from the wall outlet (Figure 75).

4. Remove the manifold cover/ outer door from the

unit by depressing on the lower portion and pulling

outward.

5. Remove the air pressure tubing from the air

pressure switch by pulling downward on the

tubing at the connection to the air pressure switch

(Figure 76).

6. Using a phillips head screwdriver, remove the 4

screws securing the air intake chamber box to the

water heater's side (Note: keep these screws in a

safe place for reinstallation later) (Figure 77).

7. Rotate the top of the air intake chamber box from

left to right (only a few inches in both directions)

while pulling outward at the bottom removing

the air intake chamber box from the combustion

chamber pipe saving the air intake chamber

gasket for reinstallation (Figure 77).

8. Upon removal of the air intake chamber box,

locate the air pressure tubing at the back of the air

intake chamber box and unplug the tubing. Note

the routing of the air pressure tubing through the

water heater's opening near the bottom. Remove

the old air pressure tubing (Figures 76 & 77).

9. Connect the new air pressure tubing into the back

of the air intake chamber box by pushing it on the

connector (Figure 78).

10. Route the new air pressure tubing through the

water heater's opening near the bottom (Note:

mirrors the position of the old tubing) (Figures 77).