7.  Restore Airplane to Normal
A.  On passenger/cargo convertible and advanced interior airplanes, install passenger cabin temperature sensor fan (Ref 21-61-34 and 21-61-35, respectively).
B.  Reconnect tubing to sensor duct (passenger cabin, if applicable) and to temperature sensor case (control cabin).
C.  Install passenger cabin temperature sensor and/or temperature bulb (Ref 21-61-31 and/or 21-62-21).
D.  If applicable, install filter in passenger air inlet grille and install air inlet grille (Ref 25-24-315).
E.  Install control cabin temperature sensor (Ref 21-61-61).
F.  Operate equipment cooling system (Ref 21-58-0) or temperature control system (Ref adjustment/test) as applicable on passenger airplanes, and on Passenger/Cargo Convertible airplanes, APU (Ref Chapter 49).
G.  Hold thin sheet of paper or streamer over control cabin and passenger cabin temperature sensor inlets and verify that air is being drawn into the inlet.
NOTE:  If it is impractical to operate equipment cooling system, temperature control system or APU (Cargo Convertible), a check for free flow of air at the control cabin exhaust tube outlet and passenger cabin outlet, if applicable, after running air through the tube a minute or so should suffice.
H.  Shut down equipment cooling and APU if no longer required.
5C8 
Jun 20/85  BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details.  21-61-0 Page 703 

AIR MIX VALVE - REMOVAL/INSTALLATION
1. General
A.  Two air mix valves, one for each cooling system, are located in the air conditioning bay. Since both installations are identical only one is shown.
2.  Remove Air Mix Valve (Fig. 401)
A.  Lower air conditioning equipment bay door.
B.  Open the following circuit breakers (P6-4):
(1)  
TEMP CONTROL

(a)  
AUTOMATIC-R (passenger cabin) or AUTOMATIC-L (control cabin)

(b)  
MAN

(2)  
AIR CONDITIONING

(a)  POS IND
C.  Remove bonding jumper from mix valve.
D.  Remove position transmitter and valve actuator electrical connectors.
E.  Loosen V-clamps and slide onto adjacent ducts.
F.  Slide flexible couplings onto adjacent ducts (Ref 21-51-61, Removal/Installation).
NOTE: Support mix valve during flexible coupling removal.
G. Remove bolt attaching support rod to mix valve body and remove mix valve from airplane.
3.  Install Air Mix Valve
A.  If new flexible couplings are to be used replace existing couplings on ducts with the new couplings (Ref 21-51-61, Removal/Installation).
B.  Check that V-clamps are on ducts and raise mix valve into position.
500 
Nov 01/74  BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details.  21-61-11 Page 401 

Air Mix Valve Installation  511 
21-61-11Page 402   Figure 401 BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details.  Aug 15/68 

C.  Install bolt through support rod and mix valve lug.
D.  Install flexible couplings (Ref 21-51-61 R/I).
NOTE:  Adjust support rod as necessary for mix valve alignment with air ducts.
E.  Install V-clamps.
NOTE:  When installing mix valve V-clamp tee bolts, check that bolts do not extend below lower surface of clamp ring (Fig. 401).
F.  Check that bonding surfaces are clean then install bonding jumper.
G.  Install position transmitter and valve actuator electrical connectors.
H.  Close circuit breakers opened in 2.B.
I.  Provide electrical power.
J.  Check that pneumatic system is not pressurized.
K.  Check that applicable temperature selector is in OFF position.
L.  Check that mix valve is in full cold position and that indicator reads accordingly (See NOTE).
NOTE:  Full cold is indicated when the pointer aligns with the inner of the two closely spaced index marks at the COLD end of the indicator scale. Full hot is with pointer alignment at inner index mark at other end of scale.
M.  Open OVERHEAT circuit breaker (P6-4).
N.  If indicator reads correctly proceed to O. If not, adjust as follows:
(1)  
Remove mix valve position transmitter (potentiometer) cap, loosen transmitter retaining screws and rotate transmitter housing relative to its shaft until indicator pointer and inner index mark align.

(2)  
Tighten retaining screws.