A.O. Smith GAHH 40 100 ユーザーズマニュアル

41

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: 3/4” Open-End Wrench or Crescent 

Wrench, Phillips Head Screwdriver, Ratchet with 1/4” 

socket or 1/4” Nut Driver.

Removing Old Inner Door/Manifold/Burner Assembly:
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 81).

 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 82).

3.  Disconnect the electric connection by unplugging 

the transformer from the wall outlet (Figure 82).

4.  Remove the manifold cover/ outer door from the 

unit by depressing on the lower portion and pulling 

outward.

5.  Unplug all the electrical connections from the 

bottom of the gas control valve/thermostat   

(Figure 83).

6.   Disconnect the electrical flag terminals and air 

pressure tubing to the pressure switch (Figure 84).

7.  Using a 3/4” open end wrench or a crescent 

wrench remove the manifold tube from the gas 

control valve/thermostat (turning counterclockwise 

-natural gas). Grasp the manifold tube and push 

down slightly to free the manifold tube from the 

gas control valve/thermostat (Figure 83).

8.  Use a 1/4” nut driver or 1/4” socket & ratchet to 

loosen the 2 hex head screws on the inner door 

so the inner door/manifold/burner assembly can 

be removed (Figure 85).

9.  Remove inner door/manifold/burner assembly by 

grasping the manifold and pulling straight back. 

Care should be taken when inner door and burner 

assembly passes through jacket opening that it 

does not damage any of the electrical wiring or 

the air pressure hose (Figure 86).

g

COOLER

HOTTER

Electronic Control Display

ON/OFF 

SWITCH

ON

OFF