McQuay Seasonpak PAB-020S Installation And Maintenance Data

Brand: McQuay

Model: Seasonpak PAB-020S

Category: Split-system air conditioners

Type: Installation And Maintenance Data

BULLETIN NO.

115

AUGUST 1967

FORM 206034Y

INSTALLATION AND

MAINTENANCE DATA

MODEL PAB

AIR COOLED WATER CHILLER

7-1/2

THRU 60 TONS

INC.. 13600 INDUSTRIAL PARK BLVD., P.O. BOX 1551, MINNEAPOLIS, MINNESOTA 55440

PHONE:

377-9750

AREA CODE: 612

STANDARD WARRANTY

McQuay, Inc. warrants to the extent of the purchase price that new

products of its manufacture are, when originally sold, free of defects

in material and factory workmanship if properly installed, cared for,

and operated, under normal conditions, with competent supervision.

McQuay’s obligations under this warranty shall be fully discharged by

correction of such defects in any part or parts which, within one year

of shipment of the products to the original purchaser, shall be re-

turned

sealed containers, tagged as to serial and model numbers,

with

transportatlon

charges prepaid, to the factory or service location

designated by McQuay. McQuay shall not be liable for any loss,

domage, or expense, directly or indirectly arising from defects

its

products, the use of its products,or any other cause. McQuay does

not assume responsibility for any expenses (including labor and

travel expenses) incurred in the field incidental to the repair or re-

placement of its products.

This warronty extends only to the original purchaser and shall not

apply to any products which must be replaced because of normal wear,

which have been the subject to misuse, negligence, or accident,

which have beer repaired or altered by persons other than those

authorized by McQuay to service its products, or to any

product on

which a serial number has been altered or removed.

This warranty

does not apply to any motor, switches, controls,

accessories,

other parts, manufactured by others and purchased by

McQuay unless

the manufacturer

warrants

the same to McQuay

and

then only to the

extent of such manufacturer’s warranty to

McQuay.

The

decision

of McQuay’s service department as to whether a defect

within

the terms of this

warranty

shall

be final.

This warranty supersedes and is in lieu of

all

other warranties,

ex-

pressed or implied

ond no

representative,

dealer,

distributor or any

other person.

authorized

or permitted

to make

any other or further

warranty or to incur

obliga

McQuay to any other Lability not

strictly in accordan

further

warranty

this policy

(except to the extent that such

writing and signed by an official of Mc-

Quay for

additional

considerationn

in accordance with an established

policy for

such

further

warranties).

McQuay’s

failure

object

to provisions contained

a customer’s

purchase orders or other communications shall not be deemed a

waiver

of the terms or

conditions

hereof or acceptance of such pro-

visions

ADDITIONAL FOUR-Y EAR WARRANTY

OF MOTOR-COMPRES

In oddition to the standard warra

for further consideration, McQua

purchase price, that the motor

new unit is, when originall

factory workmanship if

under normal conditions

compressor assem

e extentof the

each such

ared for, and operated,

rvision.

The term

“motor-

lyconsisting

of the

stator,

suction valve,

dis-

in which these parts are enclosed.

warranty shall be fully discharged by

in any port or parts which, within four

ioni

of the standard one-year warranty, shall be

ainers, tagged OS to serial and model numbers,

arges prepaid, to the

factory

or service location

Mcf3irhy shall not be liable for any loss, damage, or expense, directly

IndIrectly

arising from defects in its products, the use of its prod-

ucts, or ony other cause.

McQuay

does not assume any responsibility

for any expenses (including labor and travel expenses) incurred in the

field

incidental

to the repair or replacement of its products.

This warranty extends only to the

original

purchaser and shall not

apply to any products which must be

replaced

because of normal wear,

which have been subject to misuse, negligence, or accident, or which

hove been repaired or altered by persons other than those authorized

McQuay to service its products, or to any product on which a

serial

number has been altered or removed.

The

decision

of McQuay’s service department as to whether a defect

within

the terms of this warranty shall be

flnal.

This warranty supersedes and is

lieu of all other warranties, ex-

pressed or implied and no representative, dealer, distributor, or ony

other person.

authorized or permitted to make any other or further

warranty or to incur or obligate McQuay to any other liability not

strictly

accordance with this

policy.

INSTALLATION

GENERAL

SERVICEABILITY

Equipment of this type is intended for installation by

qualified servicemen’only. As a condition of the war-

ranty, the check, test, and start-up procedure must be

performed by such personnel and properly reported on

the form provided. Failure to do so voids the warranty.

Arrangement for service should be made prior to instal-

lation, as it is not included in the warranty or the

catalog price. See warranty terms on Page 3.

The compressor compartment is accessible from the

top and two sides by easily removed panels.

All control and starting equipment is located in the

control cabinet. The control panel is protected by a

weatherproof enclosure having a

gasketed

and hinged

door.

The condenser fan motors on belt driven units are

accessible through generously sized access doors for

checking the fan motor, belts, and drives.

INSPECTION

On belt drive units, the condenser fan bearings are

equipped with external lubrication fittings.

When the equipment is received, all items should be

carefully checked against the bill of lading to be sure

that ail crates and cartons have been received. All

units should be carefully inspected for damage when

received and all damage should be reported immedi-

ately to the carrier, and a claim filed for damage. The

unit nameplate should be checked to be sure it agrees

with the power supply available.

The direct drive fan motors are serviced through the

fan opening.

REFRIGERANT CHARGE

LOCATION

Every model PAB SEASONPAK air cooled water chiller

is supplied with a full refrigerant charge for the job

requirements

(see

Table

Pages 8 and

9).

Charge for

specific units can

obtained

f’rom

the

nameplatc.

The

McQUAY

line of air cooled water chillers is de-

signed for outdoor application. The chiller unit should

be located so that all four sides of the unit have free

area for inlet air flow. The units have vertical conden-

ser air discharge, with air taken in from the underside

of the unit.

HANDLING

A level and sufficiently strong base is required to

support the SEASONPAK air cooled water chiller. If

necessary, additional supports should be provided to

transfer the weight of the unit to the nearest adequate

structural members of the building.

The unit location should be such that the service-

man has free access to the compressor compartment,

refrigerant system components (i.e., strainerdriers),

condenser fan motors, and electrical control cabinet.

\,‘ibration

isolators are recommended under all roof

mounted units or

where

vibration transmission is crit-

ical

Recommended

mounts are shown in

Table

Page 6.

Care should be taken to avoid rough handling or shock

due to dropping the unit. Never push or pull the unit

from anything other than the skids. Do not drop either

end of unit off of truck tail gate. For lifting, slings

should be provided, with spreader bars to protect the

aluminum housing. The dual units are furnished with

permanent full length skids. The single compressor

units are shipped on wooden skids. Lifting adapter

holes are furnished on the dual unit skids. Lifting

lugs are furnished on the single unit side channels.

All legs have convenient holes for use in moving the

unit.

The

single compressor unit leg base

plates

have

three holes for convenient location of legs for fasten-

ing to “I” beam or channel bases.

Page

ELECTRICAL

ELECTRICAL CONTROL CENTER

The adjustable safety controls are separated from the

starting controls by means of a partition dividing the

control cabinet and individual access doors. The con-

trol box is further arranged with a dead-front panel

which covers all

exposed electrical contacts and

terminals, to provide absolute safety for the operator.

Figure 6, Page 10, shows dead-front panel removed to

show internal controls and wiring.

FIELD WIRING

Wiring should be done in accordance with all ap-

plicable codes and ordinances.

Three main power leads must be hooked up to the

unit power terminal block. Table 8, Page 16, gives

the recommended lead wire sizes for three conduc-

tors in a raceway for a normal installation.

Maximum voltage variation equals 10% of nameplate

value. Phase voltage unbalance

must not

exceed 2%.

A flow switch (FC) is provided with the unit and

must be field wired across terminals as shown on

Diagrams 2 and 3, Pages 12 thru 15.

Refer to wiring diagrams provided with units for

specific wiring recommendations for each model.

Wiring Diagrams 2 and 3, Pages 12 thru 15, show

basic wiring and accessory circuits.

Always ground unit for safety.

FUSES AND CIRCUIT BREAKERS

The fuses and circuit breakers for the compressor,

condenser fan motor circuit and control circuit are

located in the control box. In addition, there are small

fuses for the compressor control circuit located in the

end of the compressor terminal box. Most local elec-

trical codes also require a disconnect switch in the

power supply, located within reach of the unit. In

many areas, the circuit breaker can be used in place

disconnect switch. Check on local

ordinances

covering

specific

rcquircments.

CRANKCASE HEATERS

The compressors are equipped with crankcase heaters.

Some models have heaters installed externally below

the crankcase and others have heaters inserted into

the crankcase.

When the system is to be started up initially, the

crankcase heater power should be turned on before

starting the system for a time sufficient for all

rcfrig-

erant in the crankcase to be evaporated. This should

be a minimum of 4 hours, and preferably over night.

The crankcase should be up to approximately 80 F.

before the system is started, to minimize the possibil-

ity of lubrication problems or valve damage on start

up.

LOCKOUT-TIMER OPERATION (Optional)

(Refer to Diagram

The desired time delay period is set by loosening

the nut at the actuator arm and adjusting the arm

in relation to the calibrated dial. The nut is

tightened.

The sustained contact switch is closed. (Normally

closed R2 in Diagram 2, Page 13).

The clutch motor is energized through the closed

contact. (The relay remains unenergized).

The motor drives the actuator arm and winds

the reset spring during the timed delay

period.

At the end of the delay period, the actuator arm

closes the

contact, energizing the

relay.

The

contact closes and holds the

relay

in.

2. The

contact

closes,

energizing

the load.

The

contact opens,

de-energizing

the motor.

The motor and actuator are reset by the reset

spring. The r3 contact opens up again since it

is actuated only by the actuator arm and is in-

dependent of the relay coil.

When the sustained contact switch is opened, the

relay coil becomes deenergized. The r5 contact

opens up, de-energizing the load.

The timer is now ready for the next closing of the

sustained contact switch and timed delay period.

DIAGRAM 1

LOCKOUT-TIMER

(INTERNAL WIRING)

(DIAC.

2 PAGE 13)

R3 & R4

(DIAG.

3 PAGE

LINKAGE

L---_----

Page

START-UP PROCEDURE

Do not start the SEASONPAK air cooled water chiller F.

until the following steps have been completed.

Check all auxiliary components of the installation.

Open the compressor suction and discharge shut

off valves until back seated. Back seating the

valve closes the gauge ports; however, if gauges

are provided, close valve one turn toward the closed

position. Always replace seal caps.

Open the manual liquid line shut off valve at the

condenser.

Check that circuit breakers and system switch are J.

in “off” position. Throw the main power disconnect

to “on”.

Check to see that the water temperature thermo-

stat is installed in the entering water line. The L.

thermostat well is to be full of heat conducting

compound and the bulb must be secured with the

retaining fitting.

Check the compressor oil level. Prior to start-up,

the oil level should be visible in the oil

sight-

glass.

Check the main system on-off switch to see that it

is in the“off’ position. The

pumpdown

switches

should be thrown to the “manual” position.

Check

resets of all safety controls.

Check

if crankcase heaters havewarmed the crank-

case of compressors. Start the auxiliary equipment

for the installation.

Set the circuit breakers to “on” position.

Turn on the system by pushing the system

“on-

off”

switch to “on”.

Start

unit(s)

by turning

pumpdown

switches to

“auto” position.

Page 17

OPERATION

During full load operation, check the compressor oil

level. It should be near the center of the oil sight

glass

during

operation.

Check the refrigerant

charge

frequently at the

moisture/liquid indicator. A steady clear glass of

liquid refrigerant indicates sufficient charge. A

green colored button in the center of the moisture

indicator indicates a dry system (should moisture

enter the system, the color will turn yellow). The

button was

green before it left the factory and

should be green after a period of operation on

start-up. A filter-drier core change is recommended

for a persistent yellow indicator. (Page 26).

Check the temperature control

thecmostat

by ob-

serving operation at reduced loads. The thermostat

is factory set for 44F leaving chilled water tem-

perature when the entering temperature is 54F.

Refer to CHECKING CONTROLS section, Pages

20 and 21.

Checkvoltage and amperage of the compressor

mo-

tor(s)

and fan motors (see Field Wiring, Page

11).

When gauges ace furnished, close gauge

ports

back seating valves after readings ace checked.

This will prolong the gauge life and prevent

refrig-

erant loss. Replace seal caps.

See SERVICE INFORMATION section, Pages 28

and 29 for Trouble Shooting

Chart.

PERIODIC SERVICE

(At end of first week of operation and once a month

thereafter.)

A. Turn on water circulating pump.

Check

compressor oil level. Oil should cover ap-

proximately

l/2

of the oil level glass.

Copeland

Compressors ace furnished with oil fill plug on

the side of crankcase, should it be necessary to

add oil. (See Page 25, Paragraph E).

B. Turn

pumpdown

switches

and S4

to "auto”

posi-

tion.

Check liquid sight glass ahead of expansion valve

for proper refrigerant charge.

C. Observe operation for several minutes, noting

un-

usual sounds, or possible unusual cycling of

compressors.

EXTENDED SHUTDOWN

belt driven units,

check

belt tension and ob-

serve condition of belts.

A. Close the liquid line shut-off valve.

Check the surface of the condenser coil for ob-

B. Wait for the compressor to pump down until it

struction.

If necessary, flush with cold water,

shuts off.

brush off, or use vacuum cleaner.

E. Make general inspection of entice system for any

unusual sound or condition.

NORMAL REFRIGERANT CHARGE

The condenser coil has a built-in subcooler. For opti-

mum operation. the liquid sight glass in the liquid line

between the receiver and

subcooler

should be substan-

tially free of bubbles. A completely clear sight glass

indicates a possible overcharged system. No adverse

affect need be expected unless overcharge is suffici-

ent to affect an excessive head pressure caused by

appreciable liquid flooding of condenser portion of

coil. The minimum charge at which the unit will

oper-

ate properly is with

clear

sight glass between

the

filterdrier and thermostatic expansion valve.

WEEK END OR SHORT PERIOD SHUTDOWN

Turn

pumpdown

switches

and S4 to “man”

position. The compressor or compressors will con-

tinue to run for a short period, until the system

pumps down, and stops on opening of low pccssuce

control.

Turn off water circulating pump (Water circulating

pump is often left on the line as an assist against

damage by freezing of water).

WARNING:

Do not open main

electrical

discon-

nect

switch as heater

cable

and crankcase heater

will

de-energized.

START UP FOLLOWING WEEK END SHUTDOWN

Page 18

OPERATION

Turn off the water circulating pump. (Water circu-

lating pump often is left on the line as an assist

against damage by freezing of water, if cooler is

not going to be drained).

Turn off the power to the compressor(s), condenser

fan motors, crankcase heaters, and water circu-

lating pump.

Be sure that the cooler section, and all outside

piping is properly protected from freezing down to

minus 20F.

However, it is advisable to drain the

cooler and all external piping for additional protec-

tion against extended power failure, or possible

electrical component failure.

Close the suction and discharge shut-off valves.

Tag all opened disconnect switches warning against

starting up the compressor before properly re-open-

ing the shut-off valves.

START-UP AFTER EXTENDED SHUTDOWN

Inspect all equipment.

Check surface of the condenser coil for paper

other obstruction.

Open the suction and discharge service valves.

Check circuit breakers; must be in “off’ position.

Turn on the electric power to the system.

Open the liquid line shut-off valve(s).

Check crankcase heaters and crankcase warmth.

Start the water circulating pump.

Throw

pumpdown

switches to “man” position.

Start the unit

(S1

and circuit breakers on, and

thermostat

TCl

calling for cooling).

Throw

pumpdown

switches

“auto”

for

restart

and normal operation.

After the unit has run for several minutes, check

the oil level in the crankcase. and observe flow

through the refrigerant sight glass for sufficient

refrigerant

charge.

IMPEDANCE RELAY OVERLOAD PROTECTION

In order to provide reset of the unit from the con-

ditioned space or at the unit, an impedance

relay

is incorporated in the control circuit. Basically. this

type of control is centered around a relay with a

high impedance holding coil connected in series with

the basic relays and

contactors,

but also in

parallel

with the automatic safety

reset

control or controls.

The

impedance

relay normally closed contacts are lo-

cated in the safety control circuit.

normally open

reset button installed at the panel or remotely is con-

nected

in parallel with the relay contacts.

For typical operation. refer to Diagram

Pages

and

15.

Note that coil of the impedance relay

is in

series with the group of controls Ml,

M3,

and

R3.

The

coil is also in parallel with the

high

pressure control

HP1 and the normally closed

relay

contacts

R5.

normal operation, HP1 and

are

closed

and,

there-

fore

there is no voltage across

relay

coil

R5.

However,

when

the

system goes out on high head pressure, con-

trol

HP1

opens:

coil is now in

series

with

the

group

controls

Ml,

and

R5.

Although the

relay

coil

is in

series

with the group of controls. there is

suffi-

cient

voltage

across

it to open the normally closed

contact

R5.

When

the high

pressure

control

HP1

closes

againl

on reduction in head

pressure,

t he

normally

closed

contact

is still held open

voltage across

coil

R5.

It is. therefore, necessary to push reset switch

to jumper contact

and drop out the impedance

relay

so that the system can start. A remote reset switch in

parallel with

may

installed for remotely restart-

ing the unit.

Where compressors have external overload protec-

tion. both the HPC and the external overload control

circuit is reset

the impedance circuit. Where com-

pressors have

internal

overload protection. automatic

reset,

only

the

HPC

outage

reset

the

imredance

circuit

Papa

CHECKING

CONTROLS

All controls are checked and adjusted prior to leaving

the factory. However, after the unit has operated satis-

factorily for a reasonable length of time, a check of

the operation and safety controls can be made as

indicated below:

Oil Pressur e Safety Switch

The oil failure pressure switch is activated by

pressure differential between the oil pump pres-

sure and the crankcase pressure. Upon start up,

the normally closed pressure actuated contact of

this control opens when the pressure differential

increases to about 15 psig. If oil pressure does not

reach this differential, the thermal time delay re-

mains energized and opens a bi-metallic safety

contact, de-energizing the complete control circuit.

If pressure reaches the prescribed differential

within 120 seconds, the thermal time delay is de-

energized and the control circuit remains closed.

If, during the operation, the oil pressure differen-

tial falls below 10 psig, the thermal time delay is

again energized and the control will shut down the

compressor.

To check the control, trip the circuit breaker to

the “off’ position. Throw control circuit to “on”

to pull in contactor. The contactor should drop out

after approximately 120 seconds. After checking

the control, wait approximately 2 to 3 minutes for

the bi-metal thermal element to cool and then reset

control manually. The compressor can then be

started. Repeated successive operations of the

control will require a longer period before it can

be reset, since the bi-metal thermal element will

get hotter and will take more time to cool.

High Pressure Control

The high pressure switch will shut down the com-

pressor and close the liquid line solenoid valve

when the compressor discharge pressure reaches

390

psig.

To check the control, shut down the con-

denser fan and observe the cut out point. During

testing, stand by the system on-off switch to shut

down the unit should the safety device malfunc-

tion. Be sure the gauges used are accurate. The

high pressure relief valve is set for 425 psig.

Low

Pressure

Control

This pressure switch is connected to the low side

of the system and its purpose is to shut down the

compressor at the end of the

pumpdown

cycle. It

will open at 35 psig and automatically reset at

approximately 60 psig. The control can be checked

by throwing the individual

pumpdown

switches to

the manual position and observing the cutout point

on the gauge.

Freezestat Thermostatic Contro l

(TC2)

This control has a bulb located in a well in the

water piping leaving the cooler. To check this con-

trol, remove the operating thermostat bulb in enter-

ing water to chiller from its well to prevent it from

shutting down the system. Then drop the water

temperature until the freeze control in the leaving

water of chiller shuts down the system. The control

should be set to cut out when the water tempera-

ture leaving the chiller reaches 36F

1F.

Thermostat

(TC1)

The thermostat supplied on all packaged water

chillers are factory calibrated for use in the return

water line to the cooler inlet. The thermostat bulb

is installed in a well in the return water line in

order to be more stable under temperature changes

due to load conditions. Figure 9, Page 24, illus-

trates the recommended method of installing the

bulb and well in the return water line. The return

water does not change temperature as rapidly as

the outlet

becaus e of the “fly wheel effect” of the

total water system. This results in a stable, non-

recycling control of the outlet water temperature.

Normally the thermostat requires no adjustment

in the field other than the dial setting for the re-

quired control point. The control is preset at the

factory

maintain a 44F average leaving water

temperature throughout the loading and unloading

sequence of the unit, based on a full load cooling

range of 10F. It should be realized, however, that

there will be a fluctuation in the leaving water

temperature as the unit cycles, unloads and loads.

The magnitude of fluctuation will decrease as the

number of capacity control steps increases.

On a two stage thermostat, the dial setting indi-

cates the average leaving water temperature that

the control will maintain. At a 44F setting, the

high stage should actuate at approximately

5lF

return

water

and

leaving

based

cooling

nge

The low stage will open at 46F return or

41F leaving

(5O

TD at 50% capacity).

Page

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McQuay Seasonpak PAB-020S Installation And Maintenance Data

Brand: McQuay

Model: Seasonpak PAB-020S

Category: Split-system air conditioners

Type: Installation And Maintenance Data

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McQuay Seasonpak PAB-020S Installation And Maintenance Data

McQuay Seasonpak PAB-020S Installation And Maintenance Data

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