Freon System Checks; Installation Of Voi-Shan Seals Diagram - Piper Navajo Chieftain PA-31-350 Service Manual

CAUTION
Be careful not to seal the water drain outlets in the evaporator boxs.
f. Inspect the evaporator boxes to insure that the foam rubber gaskets are installed. These gaskets are located
at the junctures of the parts to prevent re-circulation of the cool air. If any air is recirculated. it reduces the amount
being transmitted to the outlets.
112
NOTE
USE VOI-SHAN SEALS NUMBER VSF1015A6BX (PIPER CODE 486 476) FOR 3/8 DI-
AMETER TUBE. VSF1015A8BX (PIPER CODE 486 479) FOR 1/2" DIAMETER TUBES
VSF1015A12BX (PIPER CODE 486 478) FOR
3/4"
DIAMETER TUBES
Figure 14-46. Installation of VOI-SHAN Seals
g. Inspect side panel air ducts to insure they are not crushed. The panels are usually crushed by leaning
against the side panels ,hen upholstered panels are not in place.
14-132. FREON SYSTEM CHECKS. Freon. because of its chemistry. is difficult to confine with rubber hoses and
seals. For this reason an acceptable leak rate has been established. and due to temperature and system operation the
leak rate will vary. Following are some areas of the system which should be inspected to prevent freon leaks:
a. Improper tightening of "B" nuts is a source of freon leaks. An alternate method of tightening "B" nuts in
lieu of torque values is as follows:
I. Hand tighten "B" nut: move the tube from side to side while tightening the nut to aid seating the nut
and flare to the nipple.
2.
With the proper wrench. tighten the nut 1/4 turn.
3. Loosen the "B" nut and repeat steps I and 2.
b. Flared fittings are sometimes difficult to seal. On the hard-to-get-at fittings. it may be necessary to install
Voi-Shan seals. (Refer to Figure 14-46.) I To install the seal. place seal over the nipple end and place tube flare over
seal and nipple. Tighten per the procedure given in paragraph a. except tighten only once.
CAUTION
When installing Voi-Shan seals check for cracks and scored flared ends
and nipple ends. Replace parts as necessary.
c. Leaks are most frequently found in the nacelle area or around the evaporators.
I. In the nacelle. the fittings at the condensor and at the aft side of the firewall and the fittings in the
immediate area.
Reissued: 9/23/80
ACCESSORIES AND UTILITIES
NAVAJO CHIEFTAIN SERVICE MANUAL
4H20
ACCESSORIES AND UTILITIES