®
550.13-N10Y
11
Unitary Products Group
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 (Form 515.41-N3Y) 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 vapor
and liquid connections are sealed with copper discs.
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.
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.
Make sure the refrigerant in the lines has been recovered
then drill a small hole through the discs to prevent any inter-
nal pressure from blowing them off and to allow the flow of
dry nitrogen through the connections when unbrazing the clo-
sures.
The liquid and vapor connections must be piped outside the
unit. Refer to the unit drawings for the locations and the
dimensions of these connections.
Before brazing the refrigerant lines to these connections,
remove the short panel from the unit frame and slide the
grommets onto the refrigerant lines. After the brazed joints
have cooled, slide the grommets back into place and secure
the panel to the unit frame
NOTE: These coils can only be piped from one side of the
unit.
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 13 for recommended drain
piping.
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.
SUPPLY AIR BLOWER ADJUSTMENT
The RPM of the supply air blower will depend on the required
CFM, the unit accessories and the static resistances of both
the supply and the return air duct systems. With this informa-
tion, the RPM for the supply air blower can be determined
from the blower performance in Table 6.
Knowing the required blower RPM and the blower motor HP,
the settings (turns open) for the supply air motor pulley can
be determined from Table 6
Each motor pulley has:
1.
A threaded barrel with two flats (or notched recesses
180° apart.
2.
A movable flange with one set screw.
After the movable flange has been rotated to the proper num-
ber of “turns open”, the set screw should be tightened against
the flat on the barrel to lock the movable flange in place. If
the pulley includes a locking collar, the locking collar must be
loosened to adjust the setting of the movable flange.
Note the following:
1.
The supply air CFM must be within the limitations shown
in Table 7 and 8.
2.
All pulleys can be adjusted in half turn increments.
FIGURE 13 : RECOMMENDED DRAIN PIPING
5 "
2 - 1 / 2 "
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