McQuay seasoncon ALP-067A Instruction Manual

BULLETIN NO. IM 173
JULY 1978
INSTALLATION AND
MAINTENANCE DATA
PACKAGED AIR COOLED CONDENSING UNIT
TYPE ALP-067A THRU 159A
GROUP McQUAY-PERFEX Inc. 13600 Industrial Park Blvd., P.O. Box 1551, Minneapolis, Mn. 55440 @)

NOTICE:
Installation and maintenance are to be performed only by
qualified personnel who are familiar with local codes and
regulations,and experienced with this type of equipment.
CAUTION: Sharp edges and coil surfaces are a potential
injury hazard. Avoid contact.
page 2

Nomenclature
PROPELLER FANS
LOW POWER CONSUMING
AIR COOLED CONDENSER
AL
- 089 A D
REFRIGERANT CIRCUITS
(D=Dual; S=Single)
DESIGN VINTAGE
NOMINAL CAPACITY (TONS)
Inspection
When the equipment is received,all items should be carefully checked
against the bill of lading to insure a complete shipment. All units
should be carefully inspected for damage upon arrival. All shipping
damage should be reported to the carrier and a claim should be filed.
The unit serial plate should be checked before unloading the unit to
be sure that it agrees with the power supply available.
INSTALLATION
Handling
Care should be taken to avoid rough handling or shock due to dropping
the unit.
Do not push or pull the unit from anything other than the
base, and block the pushing vehicle away from the unit to prevent
damage to the sheet metal cabinet.
(See Figure 1.)
FIGURE 1 SUGGESTED PUSHING ARRANGEMENT
GOOD PUSHING ARRANGEMENT
CABINET DAMAGE UNLIKELY
POOR PUSHING ARRANGEMENT
CABINET DAMAGE LIKELY
page 4

Never allow any part of the unit to fall during unloading or moving
as this may result in serious damage.
To lift the unit,
2+"
diameter lifting holes are provided in the base
of the unit. Spreader bars and cables should be arranged to prevent
damage to the condenser coils or unit cabinet.
(See Figure 2.)
FIGURE 2
TABLE 1
SUGGESTED LIFTING ARRANGEMENT
SPREADER BAR REQD.
-MUST USE THESE RIGGING HOLES
(NOTE
CONTROL 60x L~cATI~NI
SHIPPING WEIGHTS
ALP UNIT SIZE UNIT WEIGHT
(Ibs)
067ASlD
4125
078ASlD
4308
089A 4963
106A 5134
ALP UNIT SIZE
126A
136A
149A
159A
UNIT WEIGHT (Ibs)
6021
6095
6873
7202
Location
Due to the vertical condenser design, it is recommended that certain
precautions be taken before installation to orient the unit so that
prevailing winds blow parallel to the unit length thus minimizing
effects on condensing pressure. If it is not practical to orient
the unit in this manner,a wind deflecting fence should be consi-
dered.
It is also necessary to provide adequate clearance on all sides of
the unit for service access and satisfactory performance. At least
60 in. (1 fan diameter) should be allowed on each side of the unit
for condenser air inlet and compressor removal on units 067
& 078.
If parallel units are installed side by side, 120 in. should be al-
lowed between units. This will prevent excessive condensing temper-
atures and enhance system performance and operating economy. Clear-
ance for service access should be at least 78 in. at the control cen-
ter end for compressor removal on units 089 through 159 and 42 in.
on units 067 and 078. Allow 36 in.clearance at the end opposite
the control center for ease of access to bearings and drives.
These
clearances are illustrated in Figure 3.
page 5

FIGURE 3 CLEARANCE AROUND UNIT
t
60” MINIMUM CLEARANCE (2)
60” MINIMUM CLEARANCE (2)
NOTE:
(I) Minimum vertical clearance above unit should be 10
feet.
(2) Clearance to condenser coil must be increased if more
than one side is obstructed or between adjacent units.
Consult your
McQUAY sales representative.
Service Access
Each end of the unit must be accessible after installation for peri-
odic service work. Compressors and manual liquid line shutoff valves
are accessible from the control center end of the unit through re-
movable access panels on unit sizes 089 through 159 and hinged side
access doors on unit sizes 067 and 078. All operational, safety,
and starting controls are located in the unit control center. They
are protected by a keylocked,weatherproof enclosure which contains
internal"dead front"
doors for protection of service personnel from
high voltage starting controls while servicing low voltage opera-
tional controls. All resettable or adjustable controls are located
just below the main control center. There is one resettable control
enclosure on each side of the unit and each enclosure contains con-
trols for compressors on that side of the unit. Capped connections
for field service gauges are also located inside these enclosures.
In addition,
each of these enclosures are removable to improve access
to compressors for field replacement.
The condenser fans, motors,and drives are accessible through a walk-
in,
keylocked access door. The access door is located at the end of
the unit opposite the control center.
An internal fan guard is located below the condenser fans and drives
on units 089 through 159. This guard must be removed to service the
fan drives but MUST always be reinstalled when service work is com-
plete.
On unit sizes 067 and 078,an interlock switch kills power to conden-
ser fans whenever the door is opened for service work on fans or
drives.
CAUTION: Disconnect all power to the unit while servicing condenser
fan drives.
page 6

Vibration Isolators
Vibration isolators are recommended for all roof mounted installa-
tions or wherever vibration transmission is a consideration.
Table
2 lists spring isolators for all ALP unit sizes. Figure 4 shows
isolator locations in relation to the unit control center. Figure 5
gives dimensions that are required to secure each
McQuay isolator
selection to the mounting surface.
Table 3 shows the isolator loads at each location shown in Figure 4
and the maximum loads for each McQuay selection.
TABLE 2
VIBRATION ISOLATORS
216404B-27 2164046-26
TABLE 3 IS0 LATOR LOADS
page 7

REFRIGERANT PIPING
General
McQuay type ALP condensing units are adaptable to either chilled
water or air handling air conditioning applications. The only re-
striction on applications is that the evaporator be selected for a
system using refrigerant 22.
Evaporator Above Condensing Unit
Figure 6 shows an installation where the evaporator is installed
above the condensing unit. It is shown for an air handling instal-
lation but all components shown are recommended for chilled water
installations except that a refrigerant distributor is not usually
required for shell-and-tube evaporators.
FIGURE 6 EVAPORATOR ABOVE CONDENSING UNIT
Legend
a
Filter-drier
b Solenoid valve
:
Sight-glass/moisture indicator
Thermal expansion valve
e Suction line, pitched toward compressor
f Liquid line
9
Vibration absorber
Notes:
1. Piping shown is for one circuit only, second circuit is similar.
2. All piping & piping components are by others.
Evaporator Below Condensing Unit
Figure 7 shows an installation where the evaporator is installed be-
low the condensing unit. It is shown for an air handling installa-
tion but all components shown are recommended for chilled water in-
stallations except that a refrigerant distributor is not usually re-
quired for shell-and-tube evaporators. Mote that a double suction
riser is shown for this arrangement.
Risers "A + B" are sized so that their combined cross-sectional in-
ternal area will allow full load unit operation without excessive
pressure drop (see notes, Table 4). Riser
"B"
is sized to provide
adequate suction gas velocity for proper oil return at minimum load
conditions.
This riser becomes effective only when the trap shown
in riser "A"fills itself with oil. It should be emphasized that
the trap shown in riser "A"should be designed to contain a minimum
internal volume to keep the total system oil requirements at a mini-
mum. Table 4 gives recommended line sizes for both single and double
suction lines and for liquid lines.
page 9

Figure 9 shows typical field wiring that is required for unit instal-
lation.
Items that require field wiring are: liquid line solenoids
(SVl & SV2),
optional hot gas bypass solenoid
(SV5) and the cooling
thermostat as well as the unit power supplies.
FIGURE 9 TYPICAL FIELD WIRING
PBl
DISCONNECT UNIT MAIN
BY OTHERS--\,,< TERMINAL BLOCK
3pH ---_H ___
POWER ___/-:__
CONI, llNlT COMPRESSORS
cAND FAN MOTORS
;BK SuppLy
_ _ __I’_ - -
WH I
\SEPARATE
II?,“-IOA
LEGEND
POWER FOR CONTROLS
I
‘,‘--
DISCONNECT BY OTHERS OPTIONAL FdSEU
i g_ ~~~SLT~OM~~~,~~NNECTION
01
8
A NOTE
I
TRANSFORMER
FUSE-IO A
0 II
-FLOW SWITCH
(C.W. SYSTEMS)
irJH_WHlTt WlhlNG fNEUT1.
SVl,2-LIOUID ’ INE
SOL. VALVE
REFRIGERANT CIRCUIT I
SAFETY AND OPERATING
SVS-HOT GAS BY PASS
CONTROLS
SOL VALVE
R3,4-COMP. 384 START
TIME CLOCK;;- RELAYS
R5,6,7,E -SAFETY RELAYS
PSI.2 -PUMPDOWN
SWITCHES
TDl1,12,13-COMP SEOUEN-
CING TIME DELAYS
Rx-EVAP. FAN INTERLOCK
PREVENTS OPENING
SV’S WITHOUT LOAD
RELAYS PROVIDE
RECYCLING PUMP
DOWN DURING OFF
SEASON
REFRIGERANT CIRCUIT
2
SAFETY AND OPERATING
CONTROLS
UNIT CONDENSER
FANS
OPERATING CONTROLS
POWER SUPPLY
FOR CONTROLS
’ I 1
I I I
PUMP STARTER PUMP STARTER
CIRCUIT R9
RIO
NOTE; CIRCUIT SHOWN ASSUMES CONTINUOUS
66
T
-C
PUMP OPERATIIN~FOR INTERMITTENT
CC. W. SYSTEMS1
a0 __:
I I 1
PUMP OPERATION CONSULT McOUAY
I I I
Thermostat Wiring
Since it is impossible for McQuay to anticipate the type of installa-
tion that an ALP condensing unit may be used on, we do not factory
install a thermostat.
We do,however,
provide numbered terminals in-
side the unit control center to which a thermostat may be connected.
These terminals are shown and labeled "Terminals For Thermostat" on
the electrical schematics.
On a two circuit unit it is important to connect the thermostat so
that as successive stages of cooling are called for, the compressors
in the unit will be started to alternately increase the condenser
load from refrigerant circuit 1 to circuit 2. This is illustrated
in Table 9.
Figure 10 shows how to install 2 independent four stage
thermostats for controlling an 8 stage unit and Figure 11 shows typi-
cal field wiring for an 8 stage thermostat.
page 14

Flow Switch for Chilled Water Applications
A WATER FLOW SWITCH MUST BE MOUNTED in either the entering or leav-
ing water line to insure that there will be adequate water flow and
cooling load to the evaporator before the unit can start. This will
safeguard against slugging the compressors on start up.
It also
serves to shut down the unit in the event that water flow is inter-
rupted to guard against evaporator freeze up.
A flow switch is available from McQuay under ordering number
860-
175033x-00. It is a "paddle"
size from 1" to 6" nominal. type switch and adaptable to any pipe
Certain minimum flow rates are required
to close the switch and are listed in Table 11. Installation should
be as shown in Figure 13.
TABLE 11
FIGURE 13
FLOW SWITCH MINIMUM FLOW RATES
NOMINAL MINIMUM REQUIRED
PIPE SIZE
FLOW TO ACTIVATE
(INCHES)
SWITCH (GPM)
1
6.00
1 l/4
9.80
1 l/2
12.70
2
18.80
2 l/2
24.30
3
30.00
4
39.70
5
58.70
6
79,20
FLOW DIRECTION
MARKED ON SWITCH
1.00 NPT FLOW SWITCH
CONNECTION
G% O:Nl.,.
AFTER SWiTCH
BEFORE SWITCH
Electrical connections in the unit control center should be made at
terminals 11 and 12. The normally open contacts of the flow switch
should be wired between these two terminals. There is also a set of
normally closed contacts on the switch that could be used for an in-
dicator light or an alarm to indicate when a "no flow" condition
exists.
Evaporator Fan Interlock for Air Handler Coil Installations
It is important to interlock the air handler evaporator fan with the
condensing unit control center to insure that there will be a cooling
load on the evaporator before the unit can start, to prevent com-
pressor slugging. A pair of terminals for each refrigerant circuit
is available in the unit control center for this purpose. These
terminal numbers are shown in Figure 12.
page 18

Control Center
All electricalcontrols are enclosed in a weatherproof control cen-
UNIT LAYOUT AND PRINCIPLES OF OPERATION
ter with keylocked,hinged access doors. The control center is com-
posed of three separate enclosures. The upper enclosure is the
largest and contains all of the 208,230, or 460 volt compressor and
fan motor starting controls. Also included in this enclosure but
partitioned separately are the exposed terminal type
- 115 volt oper-
ational controls. A "dead front"cover over the high voltage section
protects service personnel from high voltage starting controls while
servicing low voltage operational controls.
Below the upper enclosure are two smaller,separate enclosures that
contain 115 volt adjustable or resettable controls. There is one of
these enclosures on each side of the unit, and each contains controls
for the compressors on that side.
Power supply conduits are intended to come into the bottom of the
upper enclosure and between the two lower enclosures. It is recom-
mended that the unit disconnect switch be mounted away from the unit
but Figure 14 recommends a unit mounting arrangement if the discon-
nect must be unit mounted.
FIGURE 14 POWER CONDUIT ENTRY
CONTROL ~
CENTER
DISCONNECT
Power
into
unit
ALP-089A THRU 159A ALP
- 067A THR U 078A
page 19