McQuay PE046W Installation Manual

USED ON ALL PE, PH. PJ, PG
TPE, TPF, TPH, TPJ MODELS
THROUGH DECEMBER
31,1982
USED ON ALL
AND PF UNITS SINGLE AND DUAL
MODELS THROUGH DECEMBER
PE046W-06OW
GENERAL
Prior to January 1, 1982 a number of different control panels were utilized on the model PE and PF centri­fugal water chilling units. None of these panels are now in production, this bulletin will provide general information on these superseded panels to assist ser­vice personnel in understanding the operating se­quence as well as providing control settings and functions.
Each unit control oanel contained necessarv
operating
and
1.
Leaving Water Cycling Thermostat (CT or LRT)
2.
Guardistor Motor Protection High Pressure Cutout (HP)
3.
4.
Low Pressure Cutout
5.
Oil Pressure Differential Switch (OD)
6.
High Oil Temperature Thermostat (OT or HOT)
7.
Vane Closed Switch (VD)
8.
Low Pressure Override Switch
9.
Oil Pump Time Delay Relay (OTD)
10.
Oil Pump Motor Capacitor
11.
Oil Pump Motor Contactor Oil Pump Motor Overload Relays (OL)
12. Electronic Control Module (Temperature and
13. Current)
Generally, control item identifications and identifying
symbols on wiring diagrams were maintained the same from panel to panel; however, there were cases where a control with the same function did carry a different symbol than had been used on similar panes of an
earlier design. The table of operating and safety con­trols starting on page 14 will identify controls and also show where differences did exist.
Notes
1.
2.
3.
-
The information following is of a general nature and applies to all control panels illustrated on pages 4 through 6, except for the temperature/ motor load control modules. Details on the dif­ferent control modules which were used are pre­sented starting on page 7.
When functions covered by a specific control panel differ from the write-up below, these differences will be covered with the control panel details on
pages 4 through 6.
A control summary table is presented starting on
page 14, the summary contains the control identifi­cations and other details of protection and operat­ing controls used in the panels.
controls.
All panels basically included:
(GR)
(LP)
(LPO)
(1
M)
protective
OPERATING SEQUENCE
The following operating sequence generally applies to control panels built through January 1, 1982. Informa-
/l/82
tion on panels utilized after 1 rent product manuals.
Assuming all interconnecting control and power wiring connections to the panel are complete and the off” switch is in the “on” position, the operating
controls will be allowed to call for unit operation.
is contained in cur-
“on-
NOTE
If power to the control panel is supplied by a separate transformer, it should be rated 2KVA with an inrush rating of The disconnect switch in the power lines supplying this transformer must be marked to prevent the switch from being opened and de-energizing the control circuit. Oil heaters are required whenever the unit is shut down. It is most important that power is available to the heaters at all times the unit is not operating.
An open section in the control circuit has been provided for connection of chilled and condenser water pump starter interlocks and flow switches. The purpose of these interlocks is to prevent the compressor from starting unless both chilled and condenser water pumps are running and flow has been established.
The cycling thermostat with its control bulb located in the leaving chilled water line will, when cooling is re­quired, close its contacts and energize the starting sequence built into the control panel (assuming the chilled water pump is running and flow has been estab­lished) closing of the cycling thermostat contacts will first call for oil pump operation by energizing the pump motor contactor and the oil cooler solenoid valve through the clutch coil contacts on the oil time delay relay (OTD).
Once the oil pump is running, two switches and a timing relay must be satisfied before the compressor will be allowed to start.
1.
The oil pressure differential switch will close when
the oil/suction pressure difference is 50 psig or
greater. If adequate oil pressure is not developed,
this switch will not close and the compressor will be
prevented from starting.
Before the compressor can start, the inlet guide vanes must be closed. The vane closed position is sensed by a pressure switch which is activated when the unloader piston has moved the guide vanes to the fully closed position capacity). Until the vanes are in the minimum
load position, the compressor starting position in
the control circuit will not be energized. The control circuit also incorporates a timing relay
(OPT) which will stop the oil pump if adequate oil pressure is not developed or the compressor does not start within 60 seconds from the closing of the cycling thermostat.
Once adequate oil pressure has been developed and the oil differential and vane closed switches have
closed, the condenser pump will be energized by the condenser pump relay contacts (HWR). The con­denser pump must cycle with the compressor. A
second set of condenser pump relay contacts com-
plete a circuit to the motor control relay(s) (MCR), energizing it or them and as a result energizing the compressor motor starter to bring the compressor on line.
Once the compressor is running, the temperature control module will direct the opening or closing of the compressor suction inlet guide vanes as require­ments for more or less cooling are relayed by the sensor located in the leaving chilled water line.
12KVA.
(10
percent
2
In addition to temperature, the current section of the control module is constantly monitoring the amount of current being drawn by the compressor motor. The current limit is manually set for the required current limit level (percent of rated load amperes). Regardless of demands for added cooling capacity, the current sensing section of the module will not permit the compressor vanes to open beyond the point where added capacity will require a value of motor current which would exceed the current limit setting.
When load conditions change and the need for less cooling is relayed to the temperature control section through the sensor in the leaving chilled water, com­pressor capacity will be reduced as the building load drops. When the compressor has been unloaded to 10 percent and the load continues to fall, leaving chilled water temperature will also drop until the setting of the cycling thermostat is reached
below design leaving water temperature), at this point the contacts in the cycling thermostat will open and the following sequence will take place:
1.
The condenser pump relay will be de-energized and the condenser pump will stop.
The motor control relay will be de-energized,
2. opening the compressor starter contacts and stopp­ing the compressor.
The oil pump will continue to run for an additional
3. 30 seconds after the cycling thermostat contacts open. Keeping the oil pump running after the com­pressor has stopped will accomplish the following:
a. Bearing lubrication is assured during the spin-
down period.
b. If the compressor cycled off before the vanes
were at minimum load position, the unloading piston will be driven toward the minimum load
position. (The vanes must be at the minimum load position before the compressor can start on the next call for cooling.
4.
The compressor and oil sump heaters are energized and stay on until the compressor starts again.
5.
A timing relay is incorporated into the control cir­cuit to limit compressor starts to not more than one every 40 minutes (timed from start). If the com-
pressor operating period prior to shutdown was
less than the time setting, it will be necessary for the time remaining on the timer to elapse before the compressor will be permitted to restart. If the
running time prior to shutdown was equal to or greater than the time setting, the compressor will be permitted to restart any time the cycling thermo­stat calls for cooling. A second type of relay was used on later units where a 20 minute interval from
stop to start was utilized.
In
the event of a power failure during compressor operation, the compressor bearings will be protected by oil stored in the emergency cylinder. The spring loaded piston in this cylinder will force oil into the
various lubrication passages and assure that all bear-
ings are lubricated during the
The exception to the above paragraph is the
through 135W units. These units utilized a solenoid valve “SD” and condensing pressure to force oil
from the supply line,oil filter and oil cooler into
the compressor bearings.
GUARDISTOR
The compressor motor is protected by the Guardistor
MOTOR PROTECTION
)
spindown
period.
(3’F
PE095W
motor protection circuit. This circuit utilizes ther­mistors buried in the motor winding to sense tem­perature changes. At a preset temperature the resis­tance of the thermistor increases rapidly, this increase in resistance and the resulting voltage drop causes the guardistor relay to open and in turn to de-energize relay
“Rl”
which opens the operating circuit and
energizes motor control relay (MCR). The Guardistor circuit, once opened, requires manual
resetting before the compressor can be restarted. If power to the control panel is interrupted for any reason, the circuit will open and will have to be
manually reset once power is restored to the control panel.

CAPACITY CONTROL MODULE

The capacity control module, regardless of the type
incorporated in the control panel, will perform the
functions described below. Where a given control
performs in a different manner, the differences will
be covered with details for that particular module
starting on page 7. The control module is powered from a 5 volt supply
(through a current transformer and resistor located in the compressor starter).
The control in response to signals relayed from a sen-
sor located in the leaving chilled water will regulate
compressor capacity by opening and/or closing two
solenoid valves “SA” (unload) and “SB” (load).
Opening and/or closing these valves permits oil pres-
sure to build up or drain from opposite ends of a
cylinder containing a floating piston. The compressor
suction inlet guide vanes are linked to the piston and
are positioned by moving it in one direction or the
other until the vane opening is adequate to satisfy
the load requirements.
The temperature control module on a call for increased
cooling capacity can continue to open the suction inlet
vanes until current drawn by the motor reaches the
setting of the current limit control. Once this current value is reached, the current limit section of the control will not permit additional loading of the compressor.
The current limit is adjustable from 40 to 100 percent
of rated load current.
The temperature controller can increase or decrease
compressor capacity through solenoid valves
and “SB”.
follows.
Loading Unloading Holding
Some older units included solenoid valve “SC”, this
valve was actuated by a low pressure switch and was
utilized to override the normal control and unload the
compressor on a sudden drop in suction pressure,
such as might be caused by a slow opening or sticking
expansion valve. On later units the “SC” valve was
eliminated and the low pressure override switch
actuated valve “SA” directly.
Most of the later panels included a service switch to permit override of the capacity control and allow manual control of compressor load level. This switch
has been included as a tool for the service mechanic and should not be utilized for any other purpose.
3
The valve action to load or unload is as
-
SB energized, SA de-energized
-
SA energized, SB de-energized
-
SA and SB de-energized
de-
“SA”
Control Panels Used on Models
Through December
SOLID STATE
TEMPERATURE/CURRENT
LIMIT CONTROLLER
SEE PAGE 8
_,
PE063,079,100
31,1982
During the production life of this control panel improvements were made. Among these improvements were a number of different temperature/current limit control modules. The different modules used are shown below with page references for
\
AND 126
ial
information.
TUBE TYPE TEMPERATURE/ CURRENT LIMIT
CONTROLLER
SEE PAGE 7
NOTE
*%mii
I
SOLID STATE
TEMPERATURE/CURRENT
LIMIT CONTROLLER
SEE PAGE 11
1.
Panel power supply - l-60-1 15V
2. Disconnect switch in power supply to the control panel must be on at all times. The oil heaters receive power through this panel.
3. If panel power is supplied through a transformer, it must have a minimum rating of 2 KVA with an inrush of 12 KVA.
4. All panels incorporate a timer to limit starts to a maximum of three (3) in a two hour period. (40 minutes between starts). Later panels 20 minutes between stop and start.
5. Earlier versions of this panel included a high discharge temperature cutout (“HDT”).
SOLID STATE TEMPERATURE/CURRENT LIMIT CONTROLLER
SEE PAGE 9
6. Later versions included a low oil temperature cutout (“LOT”).
7. Later versions included a system monitor relay and indicating light. The system monitor was utilized to indicate a problem in the system external to the unit control box. For example, the compressor starter open because its overload relays have tripped.
8. Protection against damage caused by compressor surging was added and a lockout relay and indica­ting light was incorporated on later versions of the panel. This was labeled “Surg Gard”.
4
This Control Panel was used on all models PE075W through 135W units produced.
SOLID STATE TEMPERATURE/ CURRENT LIMIT CONTROLLER
SEE PAGE 11 THIS CONTROL
MODULE IS USED AS A RETROFIT DEVICE TO
REPLACE THE ORIGINAL TUBE TYPE WHICH IS NO LONGER AVAILABLE.
1. Panel power supply - 1-60-l
15V
2. The disconnect switch in the power supply to the control panel must be on at all times. The oil
heaters receive power through this panel.
3. If panel power is supplied through a transformer,
it must have a minimum rating of 2 KVA with an inrush of 12 KVA.
4. The control panel includes a time delay relay limit compressor motor starts to a maximum of three (3) in a two hour period. (40 minutes between starts.
)
to
5. Panel includes a compressor start time delay relay (CTD) which is set for 5 seconds. This permits oil pressure to build up and bearings to be lubricated prior to having the compressor start.
6. The compressor is protected during
spindown after a power Failure by solenoid valve “SD”. This is a normally open valve when its coil is de-energized with this valve open condenser gas pressure forces oil from the oil supply line and compressor oil passages to assure bearing lubri­cation.
5
Control Panel used on all Model PF and all model
Single and Dual Units Produced through December
PEO46W
through
31,1982.
PE06OW
THIS CONTROL MODULE
HAS BEEN USED WITH
THIS CONTROL PANEL
AS A RETROFIT DEVICE.
SEE PAGE 11
1.
Panel power supply - 1-60-l 15V
CONTROL MODULE IS MOUNTED
AT REAR OF CONTROL PANEL
BUT IT CAN BE ADJUSTED
FROM THE FRONT.
SEE PAGE 10
2. The disconnect switch in the power supply to the control panel must be on at all times. The oil heaters receive power through this panel.
3. If panel power is supplied through a transformer, it must have a minimum rating of 2 KVA with an inrush of 12 KVA.
4. All panels include a timer to limit starts to a
maximum of three
(3)
in a two hour period
(40
minutes between starts).
THIS CONTROL MODULE IS
MOUNTED AT THE REAR
OF THE CONTROL PANEL
ACCESS FOR ADJUSTMENTS
REQUIRES THAT THE REAR
PANEL BE REMOVED.
SEE PAGE 9
5. The cooling tower pump motor must cycle with the compressor (lead compressor on dual com-
pressor units.) The control panel control circuit has
capacity to accomodate a pump motor starter
holding coil or relay with a maximum rating of 10 volt amperes.
6. All interlock contacts must have a minimum rating
of 5 amperes.
7. The alarm circuit will accomodate a load not
ceeding 10 volt amperes.
6
ex-
TUBE TYPE (0.45 TO 0.5 VOLTS)
CURRENT LIMIT CALIBRATION
1.
Turn the current limit adjust­ment clockwise past the 100 percent setting until it hits the stop.
2.
With the unit running check the leads on the line side of the starter to locate the phase carrying the greatest current. Attach the ammeter to this
phase. (Remember if the compressor starter is a star/ delta type, the load side leads will carry phase current. In addition, depending on the
method used to wire the line side it may also be possible to read phase current on both sides of the contactor. Phase
current.) Before attempting to calibrate this con­troller, be sure you know which current you are reading.
When the compressor motor is drawing rated load
3. amperes,
the current resistor combination located in the compressor motor starter should provide a voltage between
0.45 and 0.5 volts to the control module. If you are reading phase amperes, line amperes can be calculated. Line amperes = Phase amperes x
1.732.
4.
The selector switch located to the right of the temperature adjustment can be used to increase or decrease compressor load. Using the switch grad­ually increase the motor load to 105% of rated load amperes. the 100% point turn, the “CR1 and screws all the way clockwise. With these adjust-
ment screws all the way clockwise the current limit controller is prevented from functioning.
It may not always be possible to load the compressor to rated load amperes because of system loading conditions. When this condition exists, see Section 9 below.
5.
With the compressor drawing 105% of rated load amperes, slowly turn the counter clockwise the cover of the micro-relay is removed the action of the “CR1 and
6.
Readjust the load on the compressor to reduce the current drawn to 100% of rated load amperes. At this point slowly turn the counterclockwise
7.
Allow the unit to continue operating for a period of time and recheck the settings of “CR1 and CR2”. When checking the
necessary to temporarily place a jumper across
terminals “D and E”. (If this jumper is not used,
the compressor will not load beyond 100%
After relay “CR1 and CR2” adjustments are verified
8.
current equals 58% of line
transformer/adjustable
(If
the module will not load beyond
CR2”
adjusting
NOTE
“CRI”
adjusting screw
until the relay energizes. (If
CR2”
relays can be observed.)
“CR2”
adjusting screw
until the relay energizes.
“CR2”
adjustment it will be
1.
remove the jumper between terminals “D and E” and turn the current limit adjustment knob clock­wise against the stop. Loosen the set screw in the knob and adjust the knob to indicate 100% and retighten the set screw.
At times the system load may not be adequate to
9. allow compressor loading to rated load amperes. When this condition is encountered, reduce the current limit controller to an obtainable current value. Using this reduced current, the calibration currents can be calculated as shown below.
Example -- Assume a unit with a nameplate rated load ampere value of 400 and an operating load condition that will not allow loading the compressor beyond 320 line amperes.
Calculate the percent of full load setting amperes at the operating condition.
Load
Settrng %
,Load
Amps.
Avail.-(.OSxRated
Rated Load Amperes
z
320 - (.05x400) xl 00
zz
320 - 20 =
400
759’0
400
Load
Amps)xlOO
Calculate the calibration amperes
“CR2”
calibration amperes =
“CR 1” calibration amperes=CR2+(.05xRated
0.75xRated
=
0.75x400 = 300 amps.
=
300+(.05x400) = 320 amps
Load Amperes
Load Amperes)
If phase amperage is being read, it will be necessary to adjust the calibration amperes. Pro­ceed as shown below.
1.
Rated Load Phase Amperes
=
0.58 x Nameplate Rated Load Amperes
= 0.58 x 400 = 232
2.
Phase Amperes at Load Condition should equal
%
of rated load amperes =
3.
4.
“CR2”
phase current calibration amperes = Rated
320 x 0.58 = 185.6
Phase
Rated Load Phase Amperes
= 185.6 x 100 = 80%
232
Amperes x 100
load phase amperes x % of rated load amperes = 232 x
.80
= 185.6
5.
“CRl”
phase calibration amperes = rated load
phase amperes xl
.05 =
185.6 x 1.05 = 194.9.
TEMPERATURE CALIBRATION
1.
Set the temperature control knob to indicate the required design leaving water temperature.
2.
With the unit operating adjust the unit capacity until the required design leaving water is indi­cated on the thermometer located in the chilled water leaving the chiller. Allow the unit to run until the temperature has stabilized at the proper temperature. Check the temperature adjustment knob, if it is not reading the same as the leaving
water, loosen the set screw and set the knob to read the correct temperature.
3.
This temperature control module requires the use of a leaving water temperature sensor part number
350A160HOl
950 ohms at a temperature of 45°F. See Figure
10B. Page 12 for additional temperature vs. re-
sistance relationships for the sensor.
4.
If the panel surrounding the control module does
not have two plug buttons or holes located at about the center line of the temperature controller, it will be necessary to remove the grey panel sur-
rounding the control module. The plug buttons or holes will allow access to terminals “X and T” as
will removal of the panel.
5.
Connect a voltmeter to terminals “X and T”. (These terminals are located to the left of the tem­perature controller.)
With the leaving chilled water at the required tem-
6.
perature, turn the calibration adjustment (located below the selector switch) until the lowest possible voltage reading is obtained on the voltmeter. (This is called the null voltage). Once this voltage
.The sensor has a resistance rating of

SOLID STATE CONTROL MODULE

sett-
ing has been determined any change in capacity (increase or decrease) will cause the voltage to in-
crease above the null value.
Recheck the calibration by rotating the temperature
7.
set point adjustment knob slowly back and forth. The lowest voltage reading should be obtained when the dial reading agrees with the thermometer at the leaving water sensor.
8.
With the voltmeter still connected to terminals
“X and T” the sensitivity can be adjusted.
Set the temperature control to the design
a.
conditions.
Turn the manual selector switch to the stop
b.
position. Adjust the control point knob to obtain the
C.
lowest voltage reading possible. Adjust the sensitivity screw to obtain the lowest
d.
possible voltage reading. Remove the voltmeter and return the selector
e.
switch to the auto position and adjust the temperature control to the design point.
CURRENT LIMIT CALIBRATION
Turn the current limit adjust-
ment until it hits the stop just past 100% current limit.
With the unit running, check
the leads on the line side of the starter to locate the phase carrying the greatest current. Attach the ammeter to this phase. (Remember if the compressor starter is a star/ delta type, the load side leads will carry phase current.) In addition, depending on the
method used to wire the line
side, it may also be possible
to read phase current on both sides of the contactor. Phase
current rent.) Before attempting to calibrate this con­troller, be sure you know which current you
are reading.
With the compressor motor drawing rated load amperes, the current transformer/adjustable re­sister combination located in the starter should be delivering a 5 volt signal to the control module. If
you are reading phase amperes, line amperes can be calculated. Line Amperes = Phase Amperes,
x 1.7322.
Proper calibration of the current limit section of the control module requires that the calibration take place in steps. Begin to load the compressor until the ammeter reads 40 percent of rated load amperes, adjust the current limit calibration screw
until both the load and unload lights are out and the amber light is on. Progressively load the machine to 60, 80, and 105 percent and follow the same calibration procedure at each load level. Continue to watch the ammeter reading with the compressor
knob
clockwise
=
58% of line cur-
motor drawing 105 percent of rated current and allow the compressor to continue running. Make any fine adjustments required during this operating period.
Leave the current limit control against the stop.
5. Loosen the screw securing the knob to the shaft
and reinstall the knob so the 100 percent current
limit indication is against the stop and retighten the
locking screw. The current limit control is now calibrated.
TEMPERATURE CALIBRATION
1.
Turn the unit control point to indicate the required design leaving water temperature.
This temperature control module requires the use of
2. a leaving water temperature sensor part number 350A160H04. 55F. The sensor has a resistance rating of 40,700 ohms at a temperature of 45°F. See Figure Page 12 for additional temperature vs. resistance relationships for the sensor. If temperature is in the range of 20°F to This sensor has a resistance of 1380 ohms at 45°F. See Page 13, Fig. 1 1 B for additional relationships.
With the unit operating, adjust the unit capacity
3. until the required design leaving water temperature is indicated on the thermometer located in the chilled water leaving the chiller. Allow the unit to run until the temperature has stabilized at the proper temperature.
4.
Once the design leaving water temperature is
obtained, adjust the temperature calibration screw
until both the load and unload lights remain out.
Allow the machine to continue to run at the
5. stabilized leaving water temperatures, if an addi-
tional adjustment in calibration is required. Make
it as described in Step 4.
Remove the control point knob and reinstall it to
6.
indicate the correct leaving water temperature.
for temperatures between 35 and
4o”F,
use sensor number
35OA160H08.
10A,
8
SOLID STATE CONTROL MODULE
CURRENT LIMIT
side, it may also be possible to read phase cur-
rent on both sides of the contactor. Phase current = 58% of line current.) Before attempt­ing to calibrate this controller, be sure you know which current you are reading.
With the compressor motor drawing rated load amperes, the current transformer/adjustable re­sister combination located in the starter should be delivering a 5 volt signal to the control module.
If you are reading phase amperes, line amperes
can be calculated. Line Amperes = Phase Amperes
x 1.7322.
Proper calibration of the current limit section of the control module requires that the calibration take place in steps. Begin to load the compressor until the ammeter reads 40 percent of rated load amperes, adjust the current limit calibration screw until both the load and unload lights are out and the amber light is on. Progressively load the machine to 60, 80, and 105 percent and follow the same calibration procedures at each load level.
Continue to watch the ammeter reading with the
CALIBRATION
Turn the current limit adjustment knob clock­wise until it hits the stop
just past 100% current
limit. With the unit running, check the leads on the
line side of the starter to locate the phase car­rying the greatest cur­rent. Attach the am­meter to this phase. member if the compres­sor starter is a star/ delta type, the load side leads will carry phase current.) In addition, de­pending on the method used to wire the line
(Re-
compressor motor drawing 105 percent of rated current and allow the compressor to continue runn­ing. Make any fine adjustments required during this operating period.
5.
Leave the current limit control against the stop.
Loosen the screw securing the knob to the shaft and reinstall the knob so the 100 percent current limit indication is against the stop and retighten the locking screw. The current limit control is now calibrated.
TEMPERATURE CALIBRATION
1.
Turn the unit control point to indicate the required design leaving water temperature.
2.
This temperature control module requires the use of a leaving water temperature sensor part number
350A160H07
The sensor has a resistance rating of 2215 ohms at
a temperature of 45°F. See Figure 1 1 A, Page 13 for
additional temperature vs. resistance relationships
for the sensor. If the sensor operating temperature
is between 20 and 40°F a sensor part number
350A160H08
resistance of 1380 ohms at 45°F. See Figure 1 1 B,
Page 13 for additional information.
3.
With the unit operating, adjust the unit capacity until the required design leaving water temperature is indicated on the thermometer located in the chilled water leaving the chiller. Allow the unit to run until the temperature has stabilized at the proper temperature.
4.
Once the design leaving water temperature is ob­tained, adjust the temperature calibration screw until both the load and unload lights remain out.
5.
Allow the machine to continue to run at the stabilized leaving water temperatures, if an addi- tional adjustment in calibration is required. Make it as described in Step 4.
6.
Remove the control point knob and reinstall it to indicate the correct leaving water temperature.
for temperatures between 35 and 55F.
will be required. This sensor has a
OLD
PF SOLID STATE CONTROL MODULE
GENERAL
1.
All adjustments to the control module will re­quire removal of the
rear panel from the con-
trol box.
2.
Calibration of both cur­rent limiting and tem­perature are made at
the rear of the control
box.
3
With the
motor drawing rated load amperes the cur­rent transformer/adjust-
able resistor located in
the motor starter should be delivering a 5 volt
signal to the control module. If you are read-
compressor
phase amperes line amperes = Phase amperes x
1.732.
4.
Adequate adjustment of the current limit and temperature sections of the control module will
require that load and unload indicating lights be added to the unit. These lights should be tied in
parallel with the load and unload solenoid valves. A green light (load) should be tied in parallel with solenoid “SB” and a red light (unload) in parallel with a solenoid “SA”. Older model units will have two separate solenoids. Later units will have a com-
4-way
bination newer units the valves will be located in a box on the rear of the compressor.
valve with two solenoid coils. On
CURRENT LIMIT CALIBRATION
1. The current limit section of the control module should be set to limit the current drawn by the
9
compressor to 105 percent of rated load amperes.
This adjustment should be made in steps to ensure proper setting at the recommended 105 percent level.
The model PF unit is generally supplied with Star/
2. Delta starters mounted and wired. With the com­pressor running, check the leads on the line side of
the starter. Up through 164 amperes you may find three power leads supplying the line of contactor
#l
Number 1 with jumpers from Contactor tactor #2. three leads from the disconnect to Contactor 1 should read line amperes. Above 164 amperes, the starter will have 6 leads from the disconnect to the starter, 3 leads will be connected to Con­tactor #I
connected to these leads will read phase amperes. To check whether you are reading line or phase amperes on a star/delta starter, check the amper­age on any of the six leads on the motor side of the starter, the ammeter will read 58 percent of line
current. If the line and load side of a star/delta
starter have the same ampere reading, you are
reading phase amperes.
Adequate calibration of both the current limit and
3
temperature section of the control module will
require that indicating lights be added to each con-
trol panel. When adding these lights they should be
tied in parallel with the load (SB) solenoid and un-
load
indicate that the machine is loading, a red light
to indicate it is unloading.
4.
Attach an ammeter to the phase on the line side of
the starter carrying the greatest current.
After the indicating lights have been added, reduce
5. the setting on the current limit controller close to its minimum point and gradually load the com-
pressor until both indicating lights are out. Read the ammeter at this point and establish the percent of rated load current being drawn. (For this
An ammeter connected to any of the
and 3 to Contactor
(SA)
solenoid. A green light is suggested to
#2.
An ammeter
to Con-
illustration assume it is about 70 percent.) Increase the setting on the load limit control and gradually load the machine by increasing the compressor load and the setting of the current limit controller until the ammeter reads approximately 90 percent of rated load current and both of the indicating lights are out. Repeat this procedure once more until the compressor is drawing 105 percent of
rated load amperes.
Allow the compressor to continue running and
make any adjustment in the load limit that may be required to keep the indicating lights out when the compressor is drawing 105 percent of rated load amperes.
Reduce the load on the compressor and attempt to reload beyond ammeter reading equivalent to 105 percent of rated load amperes. When the current limit control is correctly adjusted, the
load indicating light will go out with the ammeter
indicating a current draw equivalent to 105 percent of rated load amperes.
TEMPERATURE CALIBRATION
1.
This temperature control module requires the use
of a leaving watertemperature sensor, Part Number
350A160H04.
of 40,700 ohms at a temperature of 45°F. See
Figure
versus temperature relationships for the sensor.
2.
Calibration of the temperature sensor is also made through the rear of the control box. Check the thermometer located in the leaving chilled water and adjust the temperature until the required design water temperature is obtained. At this point both the load and unload lights should be out; if they
are not, move the temperature adjustment screw
until both lights remain out.
3.
Allow the unit to continue to operate and make any
fine adjustments required during this period.
The sensor has a resistance rating
IOA,
Page 12 for additional resistance
PF
SOLID STATE CONTROL MODULE (DISCONTINUED JANUARY, 1982)
GENERAL
With the compressor motor drawing rated load amperes the current transformer/adjust­able resistor located in the
motor starter should be deliver­ing a 5 volt signal to the con-
trol module. If you are reading
phase amperes, line amperes
= phaseamperes x 1.732.
Adequate adjustment of the current limit and temperature sections of the control module will require that load and un­load indicating lights be added to the control panel. These lights should be tied in parallel
with the load and unload sole-
noid valves. A green light
(load) should be tied in parallel
with solenoid “SB” and a red
light in parallel with solenoid “SA”. Older units will have two separate sole- noid valves, later units will have a single four (4) way valve with two operating solenoid coils. On
10
newer units the valves will be located in a box attached to the rear of the compressor.
CURRENT LIMIT CALIBRATION
1.
The current limit section of the control module should be set to limit the current drawn by the compressor to 105 percent of rated load amperes. This adjustment should be made in steps to ensure proper setting at the recommended 105
percent level. The model PF unit is generally supplied with star/delta starters mounted and wired, be aware of what current value you are
reading on your ammeter.
2. With the compressor running, check the leads on the line side of the starter. Up through 164 amperes you may find three leads supplying the
line side of Contactor
tactor #I
to the three leads from the disconnect to Con-
tactor #I
amperes, the starter will have 6 leads from the disconnect to the starter, 3 leads to Contactor connected to these leads will read phase amperes.
To check whether you are reading line or phase
to Contactor
should read line amperes. Above 164
#I
and 3 to Contactor
#I
with jumpers from Con-
#2.
An ammeter connected
will
be connected
#2.
An ammeter
amperes on a star/delta starter, check the amper­age on any of the six leads on the motor side of the starter, the ammeter will read 58 percent of line current. If the line and load side of a star/ delta starter have the same ampere reading, you are reading phase amperes.
3.
As previously stated, adequate calibration of both the current limit and temperature section of the control module will require that indicating lights be added to each control panel. When adding these lights they should be tied in parallel with the load (SB) solenoid and unload (SA) solenoid. A green light is suggested to indicate the machine is loading, a red light to indicate it is unloading.
Attach an ammeter to the phase on the line side of
4. the starter carrying the greatest current.
After the indicating lights have been added, reduce
5. the setting on the current limit controller close to its minimum point and gradually load the com-
pressor until both indicating lights are out. Read the ammeter at this point and establish the percent of rated load current being drawn. (For this illustration
assume it is about 70 percent.) Increase the
setting on the load limit control and gradually load the machine by increasing the compressor load and the setting of the current limit controller until the ammeter reads approximately 90 percent of rated load current and both of the indicating lights are out.
Repeat this procedure once more until the pressor
amperes.
6.
Allow the compressor to continue running and
make any adjustment in the load limit that may be
is drawing 105 percent of rated load
com-
required to keep the indicating lights out while the compressor is drawing 105 percent of rated load
amperes.
7.
Reduce the load on the compressor and attempt to reload beyond an ammeter reading equivalent to 105 percent of rated load amperes. When the current limit control is correctly adjusted, the indicating lights will go out when the compressor is drawing a current equivalent to 105 percent of rated load amperes.
TEMPERATURE CALIBRATION
Adjust the temperature control knob to indicate the required design leaving water temperature.
This temperature control module requires the use of
a leaving water temperature sensor part number 350A160H04. 40,700 ohms at a temperature of 45°F. See Figure
IOA,
Page 12 for additional resistance versus
temperature relationships for the sensor.
With the unit operating, continue to adjust the control until the design leaving water temperature is indicated on the thermometer located in the water line leaving the chiller. Allow the unit to run
until the leaving water has stabilized at the required temperature.
Once the design water temperature is obtained,
adjust the temperature calibration screw until both the load and unload lights are out.
Allow the machine to continue to run at the sta­bilized temperature, if additional fine tuning of the calibration is required it can be done at this time.
Remove the temperature control knob and reinstall it to indicate the correct leaving water temperature.
The sensor has a resistance rating of
SOLID STATE CONTROL MODULE (USED FOR
CURRENT CALIBRATION
1.
Start the unit and place the control module selector switch in the manual position.
2.
Open the starter door and place the
amprobe drawing the highest current on the load side of the starter.
3.
Remove the control module
cover. Set current demand limit selec-
4. tor switch clockwise the stop (100%). Set the blue current limit cali-
5. bration screw (located just to
the left of the temperature con­trol stem) to the full counter­clockwise position.
6. Check the compressor motor nameplate rated load amperes
on the amprobe. Manually adjust the load until the amperes drawn by the motor match the motor rated load amperes. If a star/delta starter is being used be sure you are reading line amperage.
7. When the nameplate and are equal, turn the current limit calibration screw clockwise until the amber light just comes on and stop. This places the unit in current hold. The internal circuitry of the module will now insure that, should the current increase to 105 percent of
rated load amperes, the controller will unload the compressor. To verify that the calibration is correct, manually
(RlA)
against the amperage reading
on the power lead
amprobe
ampere values
against
11
REl-ROFlT
unload and then reload the compressor to the rated
load ampere value and verify that the current over­ride light glows. The current limit control portion of
the module is now in calibration.
8.
Check the knob setting, if it needs correcting snap
the top off the control knob, loosen the screw and
rotate the knob to indicate 100% of current. Tighten screw and replace top.
TEMPERATURE CONTROL CALIBRATION
1.
Remove control module cover.
2.
Allow unit to operate until leaving water tem­perature stabilizes. With the thermometer located in leaving chilled water, read the water temperature.
3.
On the control module turn the temperature control
knob to a point where both the unload (red) and load (green) lights remain off. Move the knob to the midpoint between these points.
4.
Check voltage between control module terminals “IOM” and “COM” using a DC voltmeter. The voltage reading should be close to
5.
Read the leaving water temperature once more. Check this temperature against the temperature indicated by the pointer at the base of the tem­perature control stem. If they do not agree, hold the stem and rotate the pointer until it indicates a temperature on the scale corresponding to the thermometer reading.
6.
Replace the control module cover. Check the temperature indicated by the knob against the cover temperature scale. If the reading is not correct, snap the top off the knob, loosen the screw and rotate the knob until it indicates the correct temperature. Tighten the screw and replace the top of the knob.
ON MANY OLDER
7.5V
UNlTS)
(
f
0.5V).
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