035-18877-001-B-0203
10
Unitary Products Group
DRAIN CONNECTION
The drain line MUST be trapped because the coil is located
on the negative side of the supply air blower, and it must be
protected from freezing temperatures.
A 7/8” OD drain connections extends through right hand side
of the cabinet. Refer to Figure 9 for recommended drain pip-
ing.
The drain connection is located on the same side of the unit
as the refrigerant connections. The line should be insulated
where moisture drippage will be objectionable or cause dam-
age to the area.
The 3” dimension must equal or exceed the negative static
pressure developed by the supply air blower. If it does not the
condensate will not drain properly and may overflow the drain
pan. The trap must be at least 2-1/2” deep to maintain a
water seal under all operating conditions, especially during
blower start-up.
NOTE:
The unit may have to be raised off the floor to allow
enough height for the trap.
REFRIGERANT MAINS
Many service problems can be avoided by taking adequate
precautions to provide an internally clean and dry system and
by using procedures and materials that conform with estab-
lished standards.
Use hard drawn copper tubing where no appreciable amount
of bending around pipes or other obstructions is necessary.
Use long radius ells wherever possible with one exception -
small radius ells for any traps in a vapor riser. If soft copper is
used, care should be taken to avoid sharp bends which may
cause a restriction.
Fiber glass insulation and a sealing material such as perma-
gum should be packed around refrigerant lines where they
penetrate a wall to reduce vibration and to retain some flexi-
biltiy.
Support all refrigerant lines at minimum intervals with suitable
hangers, brackets or clamps.
Braze all copper to copper joints with Sil-Fos 5 or equivalent
brazing material.
DO NOT USE SOFT SOLDER
.
Never braze or solder the liquid and vapor lines together for
support purposes, they must be completely insulated, one
from the other.
Refer to the installation instructions (035-18549-001) for the
matching outdoor unit for piping limitations, line sizes and
other design considerations.
INSTALLING REFRIGERANT MAINS
The units are evacuated and dehydrated at the factory and
shipped with a holding charge of Refrigerant-22. The suction
and liquid connections are sealed with copper discs. Refer to
the appropriate condensing unit installation instructions for
charging data.
Before starting installation of the mains be sure the unit has
not developed a leak in transit by drilling a small hole in the
sealing discs. If pressure still exists, the circuit may be con-
sidered leak free. If pressure does not exist the coil should be
leak tested.
NOTE:
To
minimize the possibility of system failure
due to dirt and moisture, a filter-drier must be
installed in the liquid line as close to the evap-
orator as possible. Filter-driers are not sup-
plied with the evaporator blowers. They are
supplied with the matching condensing sec-
tions.
If solenoid valves are required, they must be purchased and
installed in the field. 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 liquid and suction connections must be piped outside the
unit. Refer to the unit drawing for locations and the dimen-
sions of these connections.
FIGURE 9 - RECOMMENDED DRAIN PIPING
5 "
2 - 1 / 2 "
P L A S T I C
E L L
S T E E L
S T U B
C O N N E C T I O N
H O S E C L A M P S
E V A P O R A T O R
C O I L
D R A I N P A N
D R A I N
P L U G
Dry nitrogen should flow through the system at
all times when heat is being applied and until
the joint has cooled.
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