035-18204-001-B-0703
12
Unitary Products Group
EXTENDING THE SERVICE PORTS
(Refer to Figure 6.)
1.
Loosen the screws securing the service ports in
shipping position.
2.
Push the service ports through the corner post.
3.
Tighten the screws to secure the service ports for
installation.
INSTALLATION
Since the condensing units are shipped with a holding
charge of refrigerant-22, they can be checked for a
refrigerant leak by depressing the stem on either of the
service ports that extend through the cabinet. As soon
as some internal pressure is relieved release the stem.
DO NOT release the entire holding charge.
If the unit has already lost its holding charge, it should
be leak tested and the necessary repairs should be
made. If the unit has maintained its holding charge, you
can assume that it has no leaks and proceed with the
installation.
Before installing the liquid line between the condensing
unit and the evaporator coil, prepare as follows:
1.
Burnish the external surfaces of the liquid connec-
tion on the condensing unit and the end of the field-
supplied piping for the liquid line.
NOTE:
Clean surfaces are essential for a well-brazed
connection.
2.
Carefully clean the internal surfaces of the above.
Any particles left on these surfaces may lead to a
future system malfunction.
NOTE:
Use only copper tubing that has been espe-
cially cleaned and dehydrated for refrigerant
use. If the tubing has been open for an
extended period of time, it should be cleaned
before being used.
The liquid line connections can now be brazed while
maintaining a minimum flow of dry nitrogen through the
piping as follows:
1.
Remove the cap from the 1/4" access port on the
liquid line service valve.
2.
Connect a supply of dry nitrogen to this access
port.
NOTE:
The filter-drier should be installed in the liquid
line as close to the evaporator coil as possible.
Do not allow the filter-drier to be exposed to
the atmosphere for an extended period of time.
Once it absorbs moisture from the atmo-
sphere, it loses its effectiveness.
3.
The matched air handlers are shipped with a small
R-22 charge and they should be checked for leaks
before installation. Drill a small hole through the
sealing cap or disc in both the liquid and suction
connection. If there is a pressure release, the
evaporator has no leaks and you can proceed with
installation. If the charge has been lost, the coils
should be leak tested and the necessary repairs
made.
4.
Move the dry nitrogen supply from the access port
on the liquid line service valve of the condensing
unit to the hole through the suction disc on the
evaporator coil.
5.
Unbraze the coil's liquid line disc while maintaining
a flow of dry nitrogen across the connection and
through the hole in the liquid line disc.
NOTE:
If the liquid line has a solenoid valve, the valve
should be opened manually to permit the nitro-
gen to flow freely.
6.
After the disc has been removed, burnish the exter-
nal surfaces and clean the internal surfaces as out-
lined above.
7.
Move the dry nitrogen supply back to the access
port on the liquid line service valve.
Dry nitrogen should always be supplied
through a connection while it is being brazed or
unbrazed because the temperature required to
make or break a brazed joint is sufficiently high
to cause oxidation of the copper unless an inert
atmosphere is provided. The flow of nitrogen
should be continued until the joint has cooled.
When making a braze connection, wrap a wet
rag around all tubing inside the unit to help pre-
vent damage to other components.
The dry nitrogen should always be supplied
through a pressure regulating valve.