Water Furnace SAH Series Installation Manual page 10

SAH AIR HANDLER INSTALLATION MANUAL
General Installation Information cont.
Air Handler Installation
The air handler is attached to the shipping pallet with four
external shipping brackets.
An air filter must always be installed upstream of the air
coil on the return air side of the air handler and must be
field supplied. Filtration can be added external to the unit
or the integral filter rack may be used. A 1" filter access rack
has been built into the cabinet. Remove the filter access
cover and install the proper sized filter. Standard 1" size
permanent or throw away filter may be used. If there is
limited access to the filter rack for normal maintenance, it is
suggested that a return air filter grille be installed. Be sure
that the return duct is properly installed and free of leaks
to prevent dirt and debris from bypassing the filter and
plugging the air coil.
The cabinet should be sealed so that unconditioned warm
air can not enter the cabinet. Warm air will introduce
moisture into the cabinet which could result in water blow-
off problems, especially when installed in an unconditioned
space. Make sure that the liquid line, suction line and drain
line entry points into the cabinet are well sealed. Use the
butyl tape supplied with the air handler to seal around the
copper lines entering the cabinet.
All wall penetrations should be sealed properly. The line
set should not come into direct contact with water pipes,
floor joists, wall studs, duct work, floors, walls and brick. The
line set should not be suspended from joists or studs with
a rigid wire or strap which comes into direct contact with
the tubing. Wide hanger straps which conform to the shape
of the tubing are recommended. All line sets should be
insulated with a minimum of 3/8" closed cell insulation. The
line set insulation should be pliable, and should completely
surround the refrigerant line. As in all R-410a equipment,
a reversible liquid line filter drier is required to insure all
moisture is removed from the system. This drier is factory
installed in the Manufacturers Split compressor section.
This drier should be replaced whenever "breaking into" the
system for service. All exterior insulation should be painted
with UV resistant paint or covering to insure long insulation
life.
Connection to the Coil
Connect the refrigerant line set to the 'A' coil tubes.
Nitrogen should be bled through the system at 2 to 3 PSI
to prevent oxidation inside the refrigerant tubing. Use a low
silver phos-copper braze alloy on all brazed connections.
The Split compressor section is shipped with a factory
charge and the service valves are not to be opened until the
line set and air handler have been leak tested, purged and
evacuated. A damp towel or heat sink should be used on
the service valves to prevent damage caused by excessive
heat.
Refer to the Refrigerant Line Sizing table to determine the
proper line set configuration for the system being installed.
Line sets over 60 feet in length are not recommended. If the
line set is kinked or deformed and cannot be reformed, the
bad section of pipe should be replaced. A restricted line set
will affect unit performance. Line sets should be routed as
directly as possible, avoiding any unnecessary bends and
turns.
VAPOR LINE
THERMAL
EXPANSION
VALVE BULB
(Cover completely
with insulation
provided)
TXV
EQUALIZER
LINE
Leak Testing
The refrigeration line set must be pressurized and checked
for leaks before purging and charging the unit. To pressurize
the line set, attach refrigerant gauges to the service ports
and add an inert gas (nitrogen or dry carbon dioxide)
until pressure reaches 60 to 90 PSIG. Never use oxygen or
acetylene to pressure test the system. Use an electronic leak
detector or a good quality bubble solution to detect leaks
on all connections made in the field. Be sure to check the
service valve ports and stems for leaks. If a leak is found,
repair it and repeat the above steps. For safety reasons do
not pressurize the system above 150 PSIG. Purge pressure
from the line set slowly when the pressure test is complete.
The system is now ready for evacuation.
System Evacuation
Ensure that the line set and air coil are evacuated before
opening service valves. The line set and air coil must be
evacuated to 250 microns with a good quality vacuum
pump and use a vacuum gauge to ensure that air and
moisture are removed. With the system shut off from the
vacuum pump a sufficient system vacuum is achieved when
a 500 micron vacuum can be held for 30 minutes. A fast
rise to atmospheric pressure indicates a leak, while a slower
rise to around 1500 microns indicates moisture is still
present in the system and further evacuation is required.
10
LIQUID LINE
THERMAL
EXPANSION
VALVE
DISTRIBUTOR
BODY