McQuay seasoncon ALP-159A Installation And Maintenance Data

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

(N

OTE

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

c

AND 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

PUMP STARTER

CIRCUIT

R9

RIO

NOTE; CIRCUIT SHOWN ASSUMES CONTINUOUS

6

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 electrical

controls 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

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