York YCUL0016 - Manual (Page 116)

YORK INTERNATIONAL 116 YORK INTERNATIONAL 117
FORM 150.63-EG1
UNIT LOCATION
The YCUL Condensing Units are designed for outdoor
installation. When selecting a site for installation, be
guided by the following conditions:
1.For outdoor locations of the unit, select a place having
an adequate supply of fresh air for the condenser.
2. Avoid locations beneath windows or between struc-
tures where normal operating sounds may be objec-
tionable.
3. Installation sites may be either on a roof, or at ground
level. (See FOUNDATION.)
4. The condenser fans are the propeller-type, and are
not recommended for use with duct work in the con-
denser air stream.
5. When it is desirable to surround the unit(s), it is rec-
ommended that the screening be able to pass the
required chiller CFM without exceeding 0.1" of water
external static pressure.
6. Protection against corrosive environments is available
by supplying the units with either copper fin, cured
phenolic, or epoxy coating on the condenser coils.
The phenolic or epoxy coils should be offered with
any units being installed at the seashore or where
salt spray may hit the unit.
In installations where winter operation is intended and
snow accumulations are expected, additional height
must be provided to ensure normal condenser air
flow.
Recommended clearances for units are given in DIMEN-
SIONS. When the available space is less, the unit(s)
must be equipped with the discharge pressure trans-
ducer option to permit high pressure unloading in the
event that air recirculation were to occur.
FOUNDATION
The unit should be mounted on a flat and level founda-
tion, ground or roof, capable of supporting the entire
operating weight of the equipment. Operating weights
are given in the PHYSICAL DATA tables.
ROOF LOCATIONS – Choose a spot with adequate
structural strength to safely support the entire weight
of the unit and service personnel. Care must be taken
not to damage the roof during installation. If the roof is
“bonded”, consult the building contractor or architect
for special installation requirements. Roof installations
should incorporate the use of spring-type isolators to
minimize the transmission of vibration into the building
structure.
Application Data
GROUND LEVEL INSTALLATIONS – It is important
that the units be installed on a substantial base that will
not settle, causing strain on the refrigerant lines and
resulting in possible leaks. A one-piece concrete slab
with footers extending below the frost line is highly rec-
ommended. Additionally, the slab should not be tied to
the main building foundation as noises will telegraph.
Mounting holes (11/16" diameter) are provided in the
steel channel for bolting the unit to its foundation. See
DIMENSIONS.
For ground level installations, precautions should be
taken to protect the unit from tampering by or injury to
unauthorized persons. Screws on access panels will pre-
vent casual tampering; however, further safety precau-
tions, such as unit enclosure options, a fenced-in enclo-
sure, or locking devices on the panels may be advisable.
Check local authorities for safety regulations.
REFRIGERANT PIPING
When sizing refrigerant pipe for split system air condi-
tioning, consideration must be given to the: (1) Suction
line pressure drop due to friction, (2) Liquid line pres-
sure drop due to friction, (3) Suction line velocity for oil
return, and (4) Liquid line pressure drop due to vertical
rise. Refer to DESIGN PARAMETERS for friction losses
for both the suction and liquid lines for the condensing
unit.
On a system where the evaporator blower is located
below the condensing unit, the suction line must be
sized for both pressure drop and oil return.
When the condensing unit is located below the evapora-
tor blower, the liquid line must be designed for pressure
drop due to friction loss and vertical rise. If the pressure
drop due to vertical rise and friction loss exceeds 30 psi,
some refrigerant will flash before it reaches the thermal
expansion valve.
All horizontal suction lines should be pitched at least 1/4
inch per foot in the direction of the refrigerant flow to aid
the return of oil to the compressor. All suction lines with
a vertical rise exceeding 3 feet should have a ‘P’ trap
at the bottom and the top to facilitate oil return. Suction
lines with a vertical rise exceeding 25 feet should be
trapped every 15 feet to provide drain points for the
oil when the circuit is deactivated. When the circuit is
reactivated, oil will return to the compressor more quickly
and in smaller slugs.
For more details, refer to ASHRAE Refrigeration Hand-
book, System Practices for Halocarbon Refrigerants.