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CMWCP - 2004
“Scroll” Water-Cooled Packaged Unit
Models: MWCP 18 A MWCP 30 A MWCP 35 A MWCP 55 A MWCP 70 A MWCP 75 A MWCP 85 A
MWCP MWCP MWCP MWCP MWCP MWCP MWCP
95 A 105 A 115 A 125 A 130 A 160 A 200 A
Contents Description .................................................................................................................... 2 Specification ............................................................................................................. 3- 7 Performance Table ........................................................................................................ 8 Outlines and Dimensions ...................................................................................... 9 - 12 Installation ............................................................................................................ 13 - 14 Piping Connections ............................................................................................. 15 - 16 Duct Connections ....................................................................................................... 17 Operation ..................................................................................................................... 18 Electrical Data ............................................................................................................. 19 Electronic Controller .......................................................................................... 20 – 21 Wiring Diagrams ................................................................................................... 22 - 31 Fan Curve ............................................................................................................. 32 – 36 Maintenance................................................................................................................. 37 Trouble Shooting......................................................................................................... 38
Note: 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 with them. Warning: Moving machinery and electrical power hazards. May cause severe personal injury or death. Disconnect and lock off power before servicing equipment.
"McQuay" is a registered trademark of McQuay International. All rights reserved throughout the world. 2003 McQuay International "Bulletin illustrations cover the general appearance of McQuay International products at the time of publication and we reserve the right to make changes in design and construction at any time without notice."
Page 1
Description The McQuay “SCROLL” MWCP water-cooled packaged units are designed for duct type air-conditioning system in commercial and industrial application. An optional plenum is available for MWCP18A-MWCP70A, for free standing applications. The MWCP water-cooled packaged unit has single or multiple hermetic compressors with independent refrigerant circuits. Each refrigerant circuit consists of a high efficiency condenser, a sealed strainer, and capillary tubes. Every McQuay MWCP unit has been leak tested, evacuated and fully charged with refrigerant R22 at the factory.
High Efficiency Hermetic Compliant Scroll Compressor (MWCP18A~MWCP125A)
• • • •
Quiet operation. Unmatched reliability with 70% fewer moving parts than comparably sized reciprocating compressors. Greater capability at handling liquid and debris in the system. High efficiency performance.
Enhanced Copper Tubes Condenser (MWCP70A~200A) Extra-high efficiency is attained by special designed shell-and-tube condenser with “T” groove copper tube surfaces for superior refrigerant-water heat transfer.
Anti-Corrosion Unit Casing Unit casing is constructed of electro-galvanized steel sheet. Casing surface is finished with epoxy polyester powder coating. Therefore, units are suitable for both commercial and industrial application.
Whisper- Quiet Operation Each unit is divided into separate compartments such that compressor noise is kept away from the supply air stream. Internal insulation of 1/2 inch thick fiberglass and double blowers design (only for MWCP85A~200A) further reduce noise level.
Quality Assurance Each unit is leak-tested, evacuated, fully charged with refrigerant and run tested in McQuay’s ISO9001 certified factory.
Page 2
Specifications Specifications for 50Hz MODEL
MWCP18A
MWCP30A
MWCP35A
MWCP55A
kcal/h
14620
22360
30100
45580
60370
Btu/h
58100
88800
119600
181000
240000
W W
17000 6000
26000 9000
35000 12000
53000 21000
70200 27000
COOLING
kW
4.34 (4.16)
7.1 ( 7.1)
9.7 (9)
14.29 (13.49)
19 (18)
HEATING
kW
6.55 (6.37)
10.1 (10.1)
14.2 (13.5)
24 (23.4)
31 (30)
0 - 100
0 - 100
0-33-67-100
0 - 50 - 100
1.7 + 3.3
3.7 x 2
TOTAL COOLING CAPACITY ELECTRICAL HEATER TOTAL POWER INPUT POWER SOURCE
V/Ph/Hz
CAPACITY STEPS
%
380-415V / 3 / 50Hz 0 - 100
REFRIGERANT
R22
REFRIGERANT CHARGE
kg
1.45
2.5
REFRIGERANT CONTROL
ALUMINIUM SLIT FINS / COPPER TUBES
ROWS
3
3
3
3
3
FPI
12
12
12
13
13
TYPE FAN
3.1 CAPILLARY TUBES
TYPE EVAPORATOR
DOUBLE SUCTION MULTI-BLADE CENTRIFUGAL TYPE
DRIVE MOTOR OUTPUT
AIR FLOW EXTERNAL STATIC PRESSURE
BELT DRIVE kW
0.55 (0.37)
1.1
2.2 (1.5)
3 (2.2)
4 (3)
m³/h
2880
4200
5400
8100
10800
CFM
1694
2470
3176
4765
6353
inWg
0.31 (0)
0.39 (0)
0.39 (0)
0.59 (0)
0.59 (0)
Pa
80 (0)
100 (0)
100 (0)
150 (0)
150 (0) 12.6
TYPE CONDENSER
WATER FLOW
m³/h
3.4
5.5
8.5
11
3.5
3.7
3.8
4
4.2
LENGTH
mm
1078
1078
1278
1722
1922
WIDTH
mm
647
647
677
736
836
HEIGHT
mm
1789 (2058)
1789 (2058)
1902 (2172)
1921 (2195)
2035 (2404)
kg
205 (220)
235 (250)
280 (300)
455 (485)
610 (650)
DIMENSION
mm
825 × 565
825 × 754
1025 × 775
725 × 725
825 × 825
1
1
1
2
2
NET WEIGHT AIR FILTER
TUBE IN TUBE mH2O
WATER HEADLOSS DIMENSIONS
QUANTITY TYPE
COMPRESSOR
SCROLL
QUANTITY POWER OUTPUT
SOUND PRESSURE LEVEL
MWCP70A
kW dB(A)
1
1
1
2
2
3.79 52
6 63
7.5 65
3.79 + 7.5 67
7.5 × 2 70
Note: 1.
The nominal cooling capacity is based on the following condition: entering air temperature 26.7ºC (80ºF) db, 19.5ºC (67ºF) wb, entering cooling
2.
Capacities are gross capacities which do not include a deduction for evaporator fan motor heat.
water temperature 29.4ºC (85ºF), leaving cooling water temperature 35ºC (95ºF). 3.
External static pressures are maximum allowable ESP based on standard motors at nominal airflow.
4.
Specifications are subject to change without prior notice.
5.
The numbers in the parentheses are applicable for the units with plenum.
Page 3
MWCP75A
MODEL TOTAL COOLING CAPACITY
ELECTRICAL HEATER TOTAL POWER INPUT
COOLING HEATING
MWCP85A
MWCP95A
68270
74820
83580
91160
98900
Btu/h
270910
297400
331640
362400
393160
W
79400
97000
97200
106000
115000
W
36000
36000
42000
42000
48000
kW
22
23.5
26.5
28
32.5
kW
40
40
47.5
47.5
53.5
0 - 50 - 100
0-33-67-100
5x2
4.4 x 3
V/Ph/Hz
CAPACITY STEPS
%
380-415V / 3 / 50Hz 0 - 50 - 100
0 - 50 -100
0-46-54-100
REFRIGERANT
R22
REFRIGERANT CHARGE
kg
4.3 x 2
4.1 x 2
7.1 + 5.7
REFRIGERANT CONTROL
CAPILLARY TUBES TYPE
ALUMINIUM SLIT FINS / COPPER TUBES
ROWS
2
FPI
12
TYPE FAN
2
3
3
4
12
12
12
12
DOUBLE SUCTION MULTI-BLADE CENTRIFUGAL TYPE
DRIVE MOTOR OUTPUT
AIR FLOW
EXTERNAL STATIC PRESSURE
BELT DRIVE kW
4
4
5.5
5.5
5.5
m³/h
13600
13600
16000
16000
19800
CFM
8000
8000
9412
9412
11647
inWg
0.79
0.79
0.98
0.98
0.98
Pa
200
200
250
250
250
TYPE CONDENSER
WATER FLOW
m³/h
13.8
15
18.7
20.6
23
4.3
4.3
4.5
4.5
4.5
LENGTH
mm
1962
1962
1962
1962
2182
WIDTH
mm
1060
1060
1060
1060
1243
HEIGHT
mm
1961
1961
1961
1961
2040
kg
720
800
930
940
1010
NET WEIGHT AIR FILTER
SHELL & TUBE
mH2O
WATER HEADLOSS
DIMENSIONS
DIMENSION
mm
529 x 660
593 x 686
6
6
QUANTITY TYPE
COMPRESSOR
MWCP115A
kcal/h
POWER SOURCE
EVAPORATOR
MWCP105A
SCROLL RECIPROCATE
QUANTITY POWER OUTPUT
SOUND PRESSURE LEVEL
2
2
2
2
3
kW
9x2
9.75 x 2
11.25 + 9.75
11.25 x 2
9x3
dB(A)
72
72
74
74
75
Note: 1.
The nominal cooling capacity is based on the following condition: entering air temperature 26.7ºC (80ºF) db, 19.5ºC (67ºF) wb, entering cooling
2.
Capacities are gross capacities which do not include a deduction for evaporator fan motor heat.
water temperature 29.4ºC (85ºF), leaving cooling water temperature 35ºC (95ºF). 3.
External static pressures are maximum allowable ESP based on standard motors at nominal airflow.
4.
Specifications are subject to change without prior notice.
5.
The numbers in the parentheses are applicable for the units with plenum.
Page 4
MODEL
MWCP125A
MWCP130A
MWCP160A
MWCP200A
kcal/h
109540
112660
141040
171020
Btu/h
434690
447800
560680
678030
W
127400
131000
164000
198720
W
48000
48000
60000
60000
COOLING
kW
34.5
36.75
48
61
HEATING
kW
55.5
55.5
71
84
0-33-67-100
0-33-67-100
0 - 50 -100
0-20-40-60-80-100
7.4 x 2
(14 x 2) + 12
TOTAL COOLING CAPACITY ELECTRICAL HEATER TOTAL POWER INPUT POWER SOURCE
V/Ph/Hz
CAPACITY STEPS
%
380-415V / 3 / 50Hz
REFRIGERANT
R22
REFRIGERANT CHARGE
kg
4.5 x 3
5.8 x 3
REFRIGERANT CONTROL
CAPILLARY TUBES TYPE
EVAPORATOR
ALUMINIUM SLIT FINS / COPPER TUBES
ROWS
4
4
4
4
FPI
12
12
12
12
TYPE FAN
DOUBLE SUCTION MULTI-BLADE CENTRIFUGAL TYPE
DRIVE MOTOR OUTPUT
AIR FLOW EXTERNAL STATIC PRESSURE
BELT DRIVE kW
7.5
7.5
11
7.5x2
m³/h
22000
22000
26400
31800
CFM
12941
12941
15529
530
inWg
1.18
1.18
1.18
1.38
Pa
300
300
300
350
TYPE CONDENSER
WATER FLOW
m³/h
25.4
26.3
31
4
mH2O
4.6
4.6
4.6
5.7
LENGTH
mm
2182
2182
2182
3012
WIDTH
mm
1243
1243
1243
1534
HEIGHT
mm
2040
2040
2040
2083
kg
1030
1150
1210
1400
593 x 686
629 x 673
6
8
WATER HEADLOSS DIMENSIONS NET WEIGHT AIR FILTER
SHELL & TUBE
DIMENSION
mm
593 x 686
QUANTITY
6
TYPE COMPRESSOR
QUANTITY POWER OUTPUT
SOUND PRESSURE LEVEL
SCROLL RECIPROCATE 3
3
2
3
kW
9x3
9.75 x 3
18.5 x 2
(18.5 x 2) + 9
dB(A)
76
76
77
79
Note: 1.
The nominal cooling capacity is based on the following condition: entering air temperature 26.7ºC (80ºF) db, 19.5ºC (67ºF) wb, entering cooling
2.
Capacities are gross capacities which do not include a deduction for evaporator fan motor heat.
water temperature 29.4ºC (85ºF), leaving cooling water temperature 35ºC (95ºF). 3.
External static pressures are maximum allowable ESP based on standard motors at nominal airflow.
4.
Specifications are subject to change without prior notice.
5.
The numbers in the parentheses are applicable for the units with plenum.
Page 5
Specifications For 60Hz MODEL TOTAL COOLING CAPACITY TOTAL POWER INPUT
COOLING
MWCP18A
MWCP30A
MWCP35A
MWCP55A
kcal/h
14450
19780
27520
42140
55040
Btu/h
57320
78630
109400
167520
218800
W
16800
23000
32000
49000
64000
kW
4.09 (3.91)
6.14
8.95 (8.25)
13.11(12.31)
17.5 (16.5)
0 - 100
0 - 100
0-33-67-100
0 - 50 - 100
1.5 + 2.8
3.1 + 3.6
POWER SOURCE
V/Ph/Hz
CAPACITY STEPS
%
460V / 3 / 60Hz 0 - 100
REFRIGERANT
R22
REFRIGERANT CHARGE
kg
1.5
1.8
REFRIGERANT CONTROL EVAPORATOR FAN
3 CAPILLARY TUBES
TYPE
ALUMINIUM SLIT FINS / COPPER TUBES
TYPE
DOUBLE SUCTION MULTI-BLADE CENTRIFUGAL TYPE
DRIVE MOTOR OUTPUT
AIR FLOW EXTERNAL STATIC PRESSURE
BELT DRIVE kW
0.55 (0.37)
1.1
2.2 (1.5)
3 (2.2)
4 (3)
m³/h
2880
4200
5400
8100
10800
CFM
1694
2470
3176
4765
6353
inWg
0.31 (0)
0.39 (0)
0.39 (0)
0.59 (0)
0.59 (0)
Pa
80 (0)
100 (0)
100 (0)
150 (0)
TYPE CONDENSER
WATER FLOW
3.4
5.5
8.5
11
3.5
3.7
3.8
4
4.2
LENGTH
mm
1078
1078
1278
1722
1922
WIDTH
mm
647
647
677
736
836
HEIGHT
mm
1789 (2058)
1789 (2058)
1902 (2172)
1921 (2195)
2035 (2404)
kg
205 (220)
235 (250)
280 (300)
455 (485)
610 (650)
DIMENSION
mm
825 × 565
825 × 754
1025 × 775
725 × 725
825 × 825
1
1
1
2
2
QUANTITY TYPE
COMPRESSOR
12.6
SCROLL
QUANTITY POWER OUTPUT
SOUND PRESSURE LEVEL
150 (0) SHELL & TUBE
m³/h
NET WEIGHT AIR FILTER
TUBE IN TUBE mH2O
WATER HEADLOSS DIMENSIONS
MWCP70A
1
1
1
2
2
kW
3.54
5.04
6.75
3.54 + 6.75
6.75 × 2
dB(A)
52
63
65
67
70
Note: 1.
The nominal cooling capacity is based on the following condition: entering air temperature 26.7ºC (80ºF) db, 19.5ºC (67ºF) wb, entering cooling
2.
Capacities are gross capacities which do not include a deduction for evaporator fan motor heat.
water temperature 29.4ºC (85ºF), leaving cooling water temperature 35ºC (95ºF). 3.
External static pressures are maximum allowable ESP based on standard motors at nominal airflow.
4.
Specifications are subject to change without prior notice.
5.
The numbers in the parentheses are applicable for the units with plenum.
Page 6
MODEL TOTAL COOLING CAPACITY TOTAL POWER INPUT
COOLING
MWCP85A
MWCP105A
MWCP115A
MWCP130A
kcal/h
68800
79120
92880
103200
130720
Btu/h
273500
314530
369230
410260
519660
W
80000
92000
108000
120000
152000
kW
22
25
28
34.5
41
0-33-67-100
0 - 50 -100
4.1 + 4.4 + 4.4
7.0 × 2
POWER SOURCE
V/Ph/Hz
CAPACITY STEPS
%
460V / 3 / 60Hz 0 - 50 -100
0 - 50 - 100
0-33-67-100
REFRIGERANT
R22
REFRIGERANT CHARGE
kg
5.2 × 2
5.3 × 2
3.7 x 3
REFRIGERANT CONTROL EVAPORATOR FAN
CAPILLARY TUBES TYPE
ALUMINIUM SLIT FINS / COPPER TUBES
TYPE
DOUBLE SUCTION MULTI-BLADE CENTRIFUGAL TYPE
DRIVE MOTOR OUTPUT
AIR FLOW EXTERNAL STATIC PRESSURE
BELT DRIVE kW
4
5.5
5.5
7.5
11
m³/h
13600
16000
19800
22000
26400
CFM
8000
9412
11647
12941
15529
inWg
0.79
0.98
0.98
1.18
1.18
Pa
200
250
250
300
300
TYPE CONDENSER
WATER FLOW
m³/h
15
20.6
23
26.3
31
4.3
4.5
4.5
4.6
4.6
LENGTH
mm
1962
1962
2182
2182
2182
WIDTH
mm
1060
1060
1243
1243
1243
HEIGHT
mm
1961
1961
2040
2040
2040
kg
800
940
1010
1150
1210
NET WEIGHT AIR FILTER
SHELL & TUBE mH2O
WATER HEADLOSS DIMENSIONS
DIMENSION
mm
529 × 660
QUANTITY
593 × 686
6
6
TYPE COMPRESSOR
SCROLL RECIPROCATE
QUANTITY POWER OUTPUT
SOUND PRESSURE LEVEL
MWCP160A
2
2
3
3
2
kW
9×2
9.75 × 2
7.5 × 3
9×3
15 × 2
dB(A)
72
74
75
76
77
Note: 1.
The nominal cooling capacity is based on the following condition: entering air temperature 26.7ºC (80ºF) db, 19.5ºC (67ºF) wb, entering cooling
2.
Capacities are gross capacities which do not include a deduction for evaporator fan motor heat.
water temperature 29.4ºC (85ºF), leaving cooling water temperature 35ºC (95ºF). 3.
External static pressures are maximum allowable ESP based on standard motors at nominal airflow.
4.
Specifications are subject to change without prior notice.
5.
The numbers in the parentheses are applicable for the units with plenum.
Page 7
Performance Table WATER TEMPERATURE OFF CONDENSER
AIR ON EVAPORATOR
MWCP18A
MWCP30A
MWCP35A
MWCP55A
MWCP70A
MWCP75A
MWCP85A
MWCP95A
MWCP105A
MWCP115A
MWCP125A
MWCP130A
MWCP160A
MWCP200A
2880
4200
5400
8100
10800
13600
13600
16000
16000
19800
22000
22000
26400
31800
WB TEMP ºC
DB TEMP ºC
MODEL
NOMINAL AIR FLOW m3/h
21ºC
TOTAL CAPACITY (kW)
SENSIBLE CAPACITY (kW)
35ºC
INPUT (kW)
TOTAL CAPACITY (kW)
SENSIBLE CAPACITY (kW)
40ºC
INPUT (kW)
TOTAL CAPACITY (kW)
SENSIBLE CAPACITY (kW)
INPUT (kW)
21
15
15.42
9.82
3.46
14.53
9.58
4.24
14.25
9.66
4.56
27
19
16.99
11.49
3.56
16.00
11.12
4.34
15.61
11.18
4.71
32
23
18.32
13.08
3.66
17.59
12.96
4.45
17.57
13.28
4.83
21
15
23.13
14.90
5.71
21.79
14.27
6.94
21.37
14.34
7.45
27
19
25.48
17.35
5.87
24.00
16.70
7.10
23.42
16.89
7.69
32
23
27.48
19.81
6.02
26.39
19.48
7.28
26.36
20.06
7.88
21
15
30.84
20.39
9.43
29.05
18.94
9.01
28.49
19.12
8.88
27
19
33.97
22.69
10.16
32.00
22.02
9.70
31.22
22.29
9.52
32
23
36.63
25.97
10.79
35.18
25.54
10.45
35.14
26.32
10.44
21
15
47.23
31.46
11.67
44.49
30.61
13.99
43.63
30.98
14.95
27
19
52.02
36.73
11.97
49.00
35.57
10.29
47.81
36.00
15.40
32
23
56.10
41.79
12.27
53.87
41.26
14.63
53.81
42.62
15.76
21
15
62.65
40.60
15.52
59.01
39.06
18.60
57.88
39.71
19.88
27
19
69.01
47.34
15.92
65.00
45.70
19.00
63.42
45.85
20.47
32
23
74.41
54.24
16.31
71.46
53.09
19.45
71.38
54.25
20.95
21
15
70.85
47.61
17.82
66.73
46.18
21.52
65.45
46.73
23.05
27
19
78.03
55.32
18.30
73.50
53.58
22.00
71.71
54.00
23.77
32
23
84.14
63.02
18.77
80.81
62.06
22.54
80.72
64.09
24.34
21
15
79.04
53.11
18.97
74.45
51.52
22.98
73.02
52.14
24.64
27
19
87.06
61.73
19.49
82.00
59.78
23.50
80.00
60.24
25.41
32
23
93.88
70.32
20.00
90.15
69.24
24.09
90.05
71.50
26.04
21
15
86.75
59.34
21.63
81.71
57.28
25.95
80.14
58.34
27.73
27
19
95.55
68.99
22.18
90.00
66.69
26.50
87.81
67.35
28.56
32
23
103.03
78.51
22.74
98.95
77.28
27.13
98.84
79.47
29.23
21
15
96.39
65.93
22.78
90.79
63.64
27.41
89.05
64.83
29.32
27
19
106.17
76.65
23.37
100.00
74.10
28.00
97.57
74.84
30.21
32
23
114.48
87.23
23.97
109.94
85.86
28.68
109.82
88.30
30.93
21
15
106.03
69.66
26.23
99.87
67.11
31.79
97.95
68.37
34.08
27
19
116.78
81.05
26.95
110.00
78.32
32.50
107.32
78.99
35.15
32
23
125.93
92.56
27.66
120.93
91.18
33.32
120.80
93.86
36.02
21
15
113.74
74.84
28.23
107.13
72.53
33.79
105.08
73.24
36.08
27
19
125.28
87.45
28.95
118.00
84.37
34.50
115.13
84.85
37.15
32
23
135.09
100.51
29.66
129.73
97.95
35.32
129.58
100.42
38.02
21
15
118.56
78.01
29.96
111.67
75.60
35.98
109.53
76.34
38.46
27
19
130.58
91.14
30.73
123.00
87.95
36.75
120.01
88.45
39.62
32
23
140.81
104.76
31.51
135.23
102.10
37.63
135.08
104.69
40.56
21
15
146.51
97.72
39.41
138.00
93.70
47.02
135.35
95.42
50.16
27
19
161.37
113.44
40.39
152.00
109.29
48.00
148.30
109.89
51.63
32
23
174.01
129.46
41.37
167.11
126.67
49.12
166.92
130.36
52.82
21
15
177.36
118.30
50.32
167.06
111.93
59.78
163.85
109.78
63.69
27
19
195.35
130.30
51.54
184.00
123.28
61.00
179.52
120.28
65.51
32
23
210.65
141.14
52.75
202.29
135.53
62.39
202.06
137.80
66.99
Note: 1.
Cooling capacity based on Nominal Airflow Rate under given conditions.
2.
Direct interpolation is permissible but extrapolation is not recommended.
3.
Ratings are gross capacities. For net capacities, deduct evaporator blower motor heat.
4.
The kW input ratings listed above are compressor kW.
Page 8
Outlines and Dimensions MWCP18A/30A
PLENUM
CONDENSATE DRAI N 1"
, L H PH z
CABLE ENTRY 2" WATER OUTLET 11 4"
EMERGENCY DRAI N 1"
WATER I NLET 11 4"
INSTALLATION CLEARANCES FRONT: REAR: LEFT: RIGHT:
900 600 900 900
Dimension in mm
MWCP35A
PLENUM
CONDENSATE DRAI N 1" CABLE ENTRY 2"
INSTALLATION CLEARANCES
, L H P H z
EMERGENCY DRAI N 1"
WATER I NLET 1/14" WATER OUTLET 1/1 4"
FRONT: REAR: LEFT: RIGHT:
900 600 900 900
Dimension in mm
Page 9
MWCP55A
PLENUM
CONDENASATE RRAI N 1"
WATER I NLET 2"
INSTALLATION CLEARANCES
CABLE ENTER 2"
, L H P H z
WATER OUTLET 2" EMERGENCY DRAI N 1"
FRONT: REAR: LEFT: RIGHT:
900 600 900 900
Dimension in mm
MWCP70A
PLENUM
CONDENSATE DRAI N 1" WATER OUTLET 2" , LH P H z
CABLE ENTER 2"
WATER I NLET 2" EMERGENCY DRAI N 1"
INSTALLATION CLEARANCES FRONT: REAR: LEFT: RIGHT:
900 600 900 900
Dimension in mm
Page 10
MWCP75A/85A/95A105A INSTALLATION CLEARANCES FRONT: REAR: LEFT: RIGHT: MODEL MWP25B/ 25A MWP30B/ 30A
900 1500 900 900
N ( DI MENSI ON) 2" 2- 1/ 2"
Dimension in mm AI R FI LTER COOLI NG COI L
WATER OUTLET N EMERGENCY DRAI N 1"
WATER I NLET N CONDENSATE DRAI N 1" CABLE ENTRY 2"
, LH P H z COOL HEAT
AUTO COM P1
W- PUMP FAN
ON/OFF
COM P2 COM P3
EG SAVER
TI M E TEMP UP
TEMP DOW N
MODE
COM P
RESET
MWCP115A/125A/130A INSTALLATION CLEARANCES FRONT: REAR: LEFT: RIGHT:
900 1500 900 900
Dimension in mm
AI R FI LTER
CONDENSATE DRAI N 1"
WATER OUTLET 2 1/ "2 WATER I NLET 2 1/ 2" EMERGENCY DRAI N 1"
, LH P H z COO L HEAT
AUTO COMP1
W- PUM P FAN
ON/ O FF
COMP2 COMP3
EG SAVER
TI M E TEMP UP
TEMP DOW N
MODE
COMP
RESET
CABLE ENTRY 2"
Page 11
COOLI NG COI L
MWCP160A INSTALLATION CLEARANCES FRONT : 900 REAR : 1500 LEFT : 900 RIGHT : 900
Dimensions in mm
MWCP200A INSTALLATION CLEARANCES FRONT : 900 REAR : 1500 LEFT : 900 RIGHT : 900
Dimensions in mm
Page 12
Installation General CAUTION To protect warranty, this equipment must be installed and serviced by authorized McQuay service personnel or a qualified service person experienced in air conditioning equipment installation. Installation must comply with all applicable codes, particularly in regard to electrical wiring and other safety elements such as relief valves, HP cutout settings, design working pressures and ventilation requirements consistent with the amount and type of refrigerant charge.
Inspection As soon as the unit is received, it should be inspected for any damage that may have occurred in transit. If damage is evident, it should be noted on the carrier’s freight bill. A separate request for inspection by the carrier’s agent should be made in writing at once. Concealed damage must be reported within 15 days of receipt of shipment. Check shipment against the bill of lading to verify that all items were delivered. Any shortages should be noted on the delivery receipt, and a claim filed immediately.
Limitations 1. An excessively high waterflow and a low water temperature may cause condensate to freeze on the surface of the evaporator coil. 2. An excessively low waterflow and a high water temperature may cause the unit to shut down on its highpressure cutout. 3. These units are not suitable for outdoor installation. 4. These units should be installed in accordance with: a) Regulations of local utility or other authorities having jurisdiction. b) Wiring must conform to provisions of local ordinances.
Handling Each unit is skidded at the factory. Care should be used during handing to avoid damage to the unit and components. Normally, the unit can be moved into position using a lift truck or pipe roller and under no circumstances should they be “walked” on the corners of the crate. The skids should not be removed till the unit is set in position. If the unit must be lifted by a crane or hoist, spreader bars and pads must be used to prevent damage. (See Table 1 for shipping weights.)
Location and Clearances The packaged unit is designed for installation on a flat and level concrete foundation. It must be capable of supporting the operating weight of the unit. Table 1 –Shipping Weights MODEL
WEIGHT(kg)
MODEL
WEIGHT (kg)
MWCP18A MWCP30A
295 (315)
MWCP95A
1095
325 (345)
MWCP105A
1105
MWCP35A
375 (400)
MWCP115A
1200
MWCP55A
560 (600)
MWCP125A
1220
MWCP70A
725 (780)
MWCP130A
1340
MWCP75A
885
MWCP160A
1400
MWCP85A
965
MWCP200A
1590
NOTE: Make sure there is adequate clearances and floor strength through doors and passageways.
Page 13
The units are constructed of general purpose, indoor application and are not intended for wet, corrosive or explosive atmospheres. ON INSTALLATIONS WHERE THE UNIT OR COOLING TOWER COULD BE EXPOSED TO LOW AMBIENT CONDITIONS, FREEZE PROTECTION IS THE RESPONSIBILITY OF OTHERS. Installation should allow for water drain, ventilation and clearances for service, including removal of compressor(s) and condenser. Recommended minimum clearances are shown on the unit dimensions drawing (See page7~11.)
Acoustical Considerations With any mechanical system, a certain amount of vibration and noise is generated. To insure a successful installation of these units, McQuay has provided the following: 1. 2.
Internal vibration isolators for compressors. Acoustically treated fan section (standard).
If return air duct is to be used, a flex connector must be field supplied. Care must be exercised to isolate the unit and piping from walls and ceiling. Besides vibration which is transmitted by conduction, radiated noise and fan noise must also be addressed. Compressors, pumps etc., all generated noise can be radiated to the occupied space. The most common approach to reducing this possibility is to locate the units in least sensitive areas. This could be near stairs, elevators or lavatories. Good acoustical practices should be employed when designing the walls between the machine room and the occupied space. All openings around doors should be sealed. The return air opening must be acoustically treated. Noise will also be carried through the fan and supply ductwork to the occupied space. When the sound attenuation package is required, you should consider installing sound attenuation in the supply ductwork.
Page 14
Piping Connections General All system piping should be installed in accordance with local code ordinances. The piping should be designed with a minimum number of bends and changes in elevation to keep costs to a minimum and unit performance to a maximum. A good installation should include the following: 1. Vibration eliminators to reduce vibration and noise transmission to the building. 2. Shut-off valves to isolate the unit from the piping system during service. 3. Manual or automatic air vent valves at the high points of the system. 4. Some means of maintaining adequate system water pressure (e.g., regulating valve and/or expansion tank). 5. Install temperature and pressure indicators at the unit to aid in servicing and trouble shooting. 6. Installation of a strainer to remove foreign matter from the water before it enters the pump. It should be located far enough upstream of the pump to prevent cavitation at the inlet. Consider Water Piping All internal condenser water piping is completed factory assembled. Field piping should be connected to the pipes that are stubbed out at the panels. Supply water must be connected to the factory piping as indicated by the markings on the unit.
FIG.1-CONDENSER WATER PIPING COOLING TOWER
Water Cooling Tower Piping When installing these units with a cooling tower, some means of controlling head pressure must be provided. Water flow through the cooling tower should be constant at the same time. It must be possible to vary the water flow through the condenser to keep the condensing pressure and temperature constant according to load and outside temperature and wet bulb conditions to assure proper operation of the thermal expansion valve or valves. This may be accomplished by installing a 3-way water-regulating valve as shown in Fig.1. The valve should be set to maintain 65ºC minimum leaving condenser water temperature. The use of a three way water regulating valve with bypass is highly recommended since it maintains constant condensing pressure regardless of outside temperature conditions and insures proper operation of the evaporator expansion valve. It is important to follow the instructions of the water regulating valve manufacturer in regard to installation recommendations and valve adjustment procedures. Thermometer wells should be located at the condenser inlet and outlet to and in performance and service work.
Page 15
Condensate Drain Two standard drain connections: 1. On the drain pan that forms the partition between the coil and condensing section. 2. On the auxiliary drain pan that forms the unit base. A trap should be placed in the evaporator condensate drain line to prevent hot outside air from being pulled into the evaporator section and to allow the condensate to drain away. The trap can be placed at any location in the drain line as long as it has a minimum of 2" head as shown in Fig.2. Drain lines running to the outside of the building should be extended beyond the wall to prevent condensate from running down the building surface. Condensate Drain insulation: The drain should be insulated where water drippage, due to condensation.
FIG.2-CONDENSATE DRAIN TRAP
Page 16
Duct Connections Supply Air The standard McQuay MWCP unit is provided with a fan outlet collar for connection of supply ductwork. McQuay recommends that a straight duct having the same dimensions as the fan outlet be used. This duct should be at least 3 duct diameters in length prior to installing any elbows or transition. See Table 2 for the minimum length of straight duct required for your particular unit. Table 2 – Duct Connection Sizes MODEL MWCP18A MWCP30A MWCP35A MWCP55A MWCP70A MWCP75A MWCP85A MWCP95A MWCP105A MWCP115A MWCP125A MWCP130A MWCP160A MWCP200A
FAN SUPPLY SIZE (mm) 225 250 300 380 460 380 380 380 380 460 460 460 460 560
MINIMUM LENGTH STRAINGT DUCT (mm) 675 750 900 1140 1380 1140 1140 1140 1140 1380 1380 1380 1380 1680
If the required length of straight ductwork is not used and transitions or elbows are installed close to the fan outlet, extra pressure losses will occur. These losses are referred to as "system effects". For more details on this subject refer to A.M.C.A. Standard 210, titled "Fan and System".
Return Air The McQuay MWCP units are designed for "free air return". The minimum returns air temperature is 55ºC. The equipment room serves as the return air plenum. If the return air is ducted to the unit, a flex connection must be supplied. Only return air should be ducted to the unit. Outside air should not be brought into the return area.
Insulation Insulate ductwork that passes through unconditioned space during cooling. Insulation should include a vapour barrier to prevent absorption of moisture.
Page 17
Operation General The McQuay MWCP unit is designed for single power source connection. No separate supply is required for the controls. The units are supplied for use on 380/415V-3Ph-50Hz or 460V-3Ph-60Hz power supply. The control voltage for the control panel operation is 220~240V-1Ph-50Hz/60Hz.
Caution! • • •
• •
The unit must not be restarted within 3 minutes after shutting down. Make sure that the unit is properly grounded by checking the ground terminal. Each system contains factory mounted, wired, adjusted and tested controls required to operate and protect the unit. The control system includes compressor overload protection, motor winding protection, high and low pressure cutouts, to guard against compressor damage due to high discharge head pressure and system leakage. The unit has a single point power connection with each compressor circuit being individually fused. This will permit additional compressors to operate when on compressor are down.
Page 18
Electrical Data Install electrical wiring in accordance with the National Electric Code and/or local regulations. A fused disconnect switch must be used in a separate circuit from the main power panel. The switch should be reasonably close to the unit for convenience in servicing. Field and elementary wiring diagrams associated with the McQuay MWCP units are shown in page 17~22. The electrical data is shown in the wiring diagrams. NOTE: Elementary wiring diagrams are subject to change without notice.
Table 3 - Motor Size MODEL MWCP18A MWCP30A MWCP35A MWCP55A MWCP70A MWCP75A MWCP85A
MOTOR SIZE (kW) 0.55 (0.37) 1.1 2.2 (1.5) 3(2.2) 4(3) 4 4
MODEL MWCP95A MWCP105A MWCP125A MWCP130A MWCP160A MWCP200A
MOTOR SIZE (kW) 5.5 5.5 7.5 7.5 11 7.5 X 2
Table 4 – Motor Electrical Data MOTOR SIZE (kW) 0.37
FLA
LRA
FLA
LRA
FLA
1.17
5.57
1.07
5.1
0.94
4.47
0.55
1.53
7.65
1.40
6.86
1.26
6.55
1.1
2.94
16.16
2.69
14.80
2.24
14.54
1.5
3.70
21.30
3.39
19.50
2.92
19.14
2.2
5.08
32.10
4.65
29.40
4.20
32.50
3
6.72
43.90
6.15
40.20
5.40
46.00
4
8.70
59.40
8.00
54.50
7.20
60.00
5.5
11.90
81.60
10.90
74.40
9.49
67.38
7.5 11
15.70 22.60
104.00 153.00
14.40 20.70
95.00 140.00
11.90 17.80
85.68 122.82
380V-3P-50Hz
415V-3P-50Hz
460V-3P-60Hz LRA
After Installation But Prior To Start Up 1. 2.
Visually check power wiring for size and type. It must meet all local codes and N.E.C. codes. Verify that field wiring matches the 3-phase power requirements of the unit. See caution on schematic diagram in the control panel. 3. Check the unit visually for indication of leaks in the refrigerant circuit. 4. Check the drive alignment of the pulleys using the four-point method prior to adjusting belt tension (see page 23 for alignment and belt tension). 5. Check the fan wheel position in the scroll, by rotating the fan manually. If any rubbing occurs, make necessary corrections. 6. Install all panels on the air side of the unit after internal unit inspection is completed. 7. Be sure all sensors are installed in the ductwork (supply and return) and in the cooling water lines. Check to see that all piping such as cooling water and drains are completed and tested. The steam and drain traps must be installed. 9. Verify that water pumps (cooling) function properly and that proper flows have been set. 10. Are recommended pressure taps and temperature wells installed for trouble shooting, if required. 11. Be sure cooling tower fans are wired correctly and fans are turning in the right direction. 12. Check settings of high pressure, low pressure and low limit controls. Push all manual reset buttons to assure that controls are functional.
Page 19
Electronic Controller 1. Function Instruction Cool / Heat / Fan Mode Pre-select the compressor: Auto (COMP1&2&3) COMP1&2
COMP1&3
COMP1
COMP2&3
COMP2
COMP3
Auto.
Temperature setting ranging from 16ºC ~ 30ºC. Programmable On/Off timer with 1 hour interval. Energy saver function. Alarm function. A LED indicates the states of the unit.
2.
Controller Panel Instruction LED Di spl ay
R
Temp. Down Set t i ng. Pr eset t emp mi ni mum 16℃ Temp. Up Set t i ng. Pr eset t emp maxi mum 30℃
Mai n Power ON/ OFF
MODE Pr essi ng t hi s but t on wi l l advance t he mode i n t he f ol l owi ng sequence: COOL→ HEAT→ FAN
Ener gy Savi ng Sel ect i on. Ener gy Savi ng or nor mal r unni ng st at us can be sel ect ed.
Compr essor Runni ng Mode Sel ect i on But t on Any of t he r unni ng mode can be sel ect ed:
Ti me Set t i ng. Pr eset t i me 1 t o 15 hour
AUTO( COMP1&2&3) → COMP1→ COMP2→ COMP3
COMP2&3← COMP1&3← COMP1&2← Reset
FIG.3 – CONTROLLER PANEL
3. a) b) c) d) e)
Operation Finish checking all the items (after installation but prior to start up). Press MODE button to select the Cool/ Heat/ Fan. If required, press TIMER button to preset time. Under the cooling mode, press COMP button to pre-select the compressor. Press ON/OFF button to start up the unit. In cooling, the start sequence is, switch ON 2s water pump 10s fan 1 min COMP1(if selected) 1 min COMP2(if selected) 1 min COMP3(if selected) In heating, the start sequence is, switch ON 2s fan 5s electric heater. In fanning, the start sequence is, switch ON 2s fan.
f)
When the unit runs, you can press TEMP button or EG-SAVER button, so that the indoor temperature is according to your requirement. g) Shut off the unit. In the heating mode, the sequence is, switch OFF 2s off.
Page 20
electric heater shuts off 30s
fan motor shuts
4. ALARM FUNCTION 1). The controller board is designed with 10 alarm signals input and 1 alarm output AL1-AL2. NO.
Input
Defect Description
Defect Code
Defect Respondence
Defect Indicator
1
FL-SW
Flow switch open
E9
System stops
COOL indicator flashes quickly
2
OV-PUMP
Water pump overload
E8
System stops
W – PUMP indicator flashes
3
OV-FAN
Fan motor overload
E7
System stops
FAN indicator flashes quickly
4
OV-COMP3
COMP3 overload
E6
COMP3 stops
COMP3 indicator flashes quickly
5
OV-COMP2
COMP2 overload
E5
COMP2 stops
COMP2 indicator flashes quickly
6
OV-COMP1
COMP1 overload
E4
COMP1 stops
COMP1 indicator flashes quickly
7
HL-COMP3
E3
COMP3 stops
COMP3 indicator flashes quickly
8
HL-COMP2
E2
COMP2 stops
COMP2 indicator flashes quickly
9
HL-COMP1
E1
COMP1 stops
COMP1 indicator flashes quickly
10
TH (cool)
E0
System stops
COOL, HEAT indicator flashes quickly
11
TH (heat)
E0
Heater off, 30s, fan stops
COOL, HEAT indicator flashes quickly
COMP3 high/low pressure switch open COMP2 high/low pressure switch open COMP1 high/low pressure switch open Thermistor sensor short or open Thermistor sensor short or open
2). When it alarms, the digital segment displays the related defect code, the alarm output AL1-AL2 is closed with it (normal open), the buzzer beeps for a long time, the ON/OFF indicator and other related indicator flashes quickly with it. 3). When 2 or more than 2 defects are detected at the same time, the system will do with each defect and keep the memory, but the defect code displays the super class E0~E9. 4). When alarm signal output, press RESET switch to clear away the alarm output for convenient repair, press RESET switch again, the system will check all kinds of alarm signals and alarm output with the defect. 5). The system still remains the defective state when the defect is eliminated; only after pressing RESET switch, the system recovered to the operation state.
Page 21
Wiring Diagrams Wiring Diagrams for 50Hz MODEL : MWCP18A/30A/35A
MODEL: MWCP55A/70A
Page 22
MODEL: MWCP75A
MODEL: MWCP95A
Page 23
MODEL: MWCP85A/105A
MODEL: MWCP115A
Page 24
MODEL: MWCP130A
MODEL: MWCP160A
Page 25
MODEL: MWCP200A
Page 26
Wiring Diagrams for 60Hz MODEL: MWCP18A/30A/35A
MODEL: MWCP55A/70A/85A
Page 27
MODEL: MWCP105A
MODEL: MWCP115A/130A
Page 28
MODEL: MWCP160A
Page 29
Electrial Parameter (50Hz) Model
MWCP 18A
MWCP 30A
4
4
Power Source Power Wire (R/S/T) Power Supply Wire
Neutral Wire Earth Wire
Section Area (mm2) Quantity Section Area (mm2) Quantity Section Area (mm2) Quantity
MWCP MWCP MWCP 35A 55A 70A 380V/3N~/50Hz 4
1.5
1.5
Earth Wire
10
10
1.5
1.5
1.5
2.5
2.5
2.5
MWCP 130A
MWCP 160A
MWCP 200A
16
25
25
4
6
6
4
4
4
1.5 1
2.5
2.5
2.5
2.5 1
MWCP 95B
Neutral Wire
10
6
1.5
MWCP 105A
MWCP 115A
Power Source
Power Supply Wire
MWCP 85A
3
Model
Power Wire (R/S/T)
MWCP 75B
MWCP 125B
380V/3N~/50Hz Section Area 2 (mm ) Quantity Section Area 2 (mm ) Quantity Section Area (mm2) Quantity
16
16
16
16 3
4
4
4
4 1
4
4
4
4 1
Electrical Wiring Connection (50Hz) Thermostatic controller Contactor Overload(OL1)
Cooling tower fan motor
Breaker Overload(OL2)
Water pump motor Terminal block Contactor PCB(OV-PUMP)
Control panel
PCB(W-PUMP)
PCB(FL-SW)
OL1 Water flow switch
OL2 L
L
Cooling water pipe Note: Operate cooling in winter,We suggest adding a Thermostatic controller for cooling water to control the cooling tower fan motor.Wiring connection as drawing.
Page 30
Electrial Parameter (60Hz) Model Power Source Power Wire Power (R/S/T) Supply Wire Earth Wire
MWCP 18A
MWCP 30A
4
4
Section Area (mm2) Quantity Section Area (mm2) Quantity
4
2.5
2.5
2.5
MWCP 105A
Earth Wire
MWCP 85A
6
10
10
2.5
2.5
2.5
1 MWCP MWCP 115A 130A 460V/3N~/60Hz
Power Source Power Supply Wire
MWCP 70A
3
Model Power Wire (R/S/T)
MWCP MWCP 35A 55A 460V/3N~/60Hz
Section Area 2 (mm ) Quantity Section Area 2 (mm ) Quantity
16
16
MWCP 160A
16
25
4
6
3 4
4 1
Electrical Wiring Connection (60Hz) Thermostatic controller Contactor Overload(OL1)
Cooling tower fan motor
Breaker Overload(OL2)
Water pump motor Terminal block Contactor PCB(OV-PUMP)
Control panel
PCB(W-PUMP)
PCB(FL-SW)
OL1 Water flow switch
OL2 L
L
Cooling water pipe Note: Operate cooling in winter,We suggest adding a Thermostatic controller for cooling water to control the cooling tower fan motor.Wiring connection as drawing.
31
Fan Performance Curve Supply Air Blower Adjustment The RPM of the supply air blower will depend on the required CFM, the unit accessories and the static resistance of both the supply and the return air duct system. With this information, the RPM for the supply air blower can be determined from the fan performance curves. Knowing the required blower RPM and the blower motor HP, the supply air motor pulley can be determined. After the supply air blower motor is operating, adjust the resistance in both the supply and the return duct systems to balance the air distribution throughout the conditioned space.
Drive Alighment
Belt Adjustment
FIG.4 – ALIGNMENT AND BELT TENSION
To determine the deflection force required use the formula: Deflection = Belt Span/64 CAUTION: 1. Do not over tighten the belts or the bearings may be come damaged. The best tension for a belt drive is the lowest tension at which the belts will not slip under the highest required load. 2. The belts should be checked at a certain time in case too loose. Table 5-Belt Tensioning Information SUPER GRIPBELTS Belt Cross Section
Small P.D. Range (mm)
Deflection Force (N) Min. Max
SPZ
56~95 100~140
13 20
20 25
SPA
80~132 140~200
25 35
35 45
SPB
112~224 236~315
45 65
65 85
32
Panel Checks A. Verify 3 phases’ power to unit. B. Close units disconnect and verify that crankcase heaters are energized. Allow the heater to remain on a minimum of 24 hours before attempting startup. This is important to assure no refrigerant is in the oil startup. Fail to do this could cause compressor failure.
Initial Start Up After the operator has familiarized itself with the sequence of operation for the unit and all options provided, the unit can be put in operation. Proceed as follows. 1. Energize cooling tower water pump and tower fans. 2. Turn the fan switch to the ON position. 3. The “Sequence of Operation” instruction covered are shown in the control wiring diagrams. 4. If no unusual noise or adverse conditions exist allow the unit to run. If these conditions do exist, turn off the unit and investigate cause. Take an air flow measurement in the straight duct off the unit discharge using a pitot tube. This measurement should be taken about three quarters (3/4) of the way down the straight duct off the fan, just before any transition or elbow. If a condition of low or high air flow exists, a pulley change may be required. Once it is ascertained that the air quantity leaving the unit is at the design, the thermostats should be set to the desired space temperature. The system should now function as designed.
33
RPM
TOTAL PRESSURE - Pa
MODEL : MWCP18A
SUPPLY AIR VOLUME – CMH(1000’S)
VELOCITY PRESSURE -Pa
RPM
TOTAL PRESSURE - Pa
MODEL : MWCP30A
SUPPLY AIR VOLUME – CMH(1000’S)
VELOCITY PRESSURE -Pa
Page 34
RPM
TOTAL PRESSURE - Pa
MODEL : MWCP35A
SUPPLY AIR VOLUME – CMH(1000’S)
VELOCITY PRESSURE -Pa
RPM
TOTAL PRESSURE - Pa
MODEL: MWCP55A/75A/85A/95A/105A (MWCP75A/85A/95A/105A Use Double Blowers)
SUPPLY AIR VOLUME – CMH(1000’S)
VELOCITY PRESSURE -Pa
Page 35
RPM
TOTAL PRESSURE - Pa
MODEL : MWCP70A/115A/125A/130A/160A (MWCP115A/125A/130A/160A Use Double Blowers)
SUPPLY AIR VOLUME – CMH(1000’S)
VELOCITY PRESSURE -Pa
RPM
TOTAL PRESSURE - Pa
MODEL : MWCP200A Use Double Blowers
SUPPLY AIR VOLUME – CMH(1000’S)
VELOCITY PRESSURE -Pa
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Maintenance General At initial startup and periodically during operation, it will be necessary to perform certain routine service checks to assure the unit functions properly. This is also the best way to avoid unnecessary downtime and expense. Routine maintenance should include the following: 1. Tighten all belts, screws, and wire connections. 2. Clean evaporator coils mechanically or with cold water, if necessary. Usually any fouling is only matted on the entering air face of the coil and can be removed by brushing. 3. Align or replace belts if needed. 4. Clean or replace filters as needed. 5. Check for blockage of condensate drains. 6. Check power and control voltages. 7. Check running amperage. 8. Check operating temperatures and pressures. 9. Check and adjust temperature and pressure controls. 10. Check operation of all safety controls.
Condensers The frequency of cleaning depends on so many variables that it is impossible to recommend a schedule. Some will need cleaning once a year and in rare cases, cleaning will be required several times a year. The shell & tube condensers can be cleaned not only by mechanical methods but also by chemical methods due to its construction. McQuay does not recommend any particular chemical preparation. The same treatment may not be applicable to all installations. But in any case: a) Use only preparations from an established, reliable source. b) Follow directions exactly, particularly regarding amounts to use and flushing or neutralizing procedure after cleaning. Proper operation cooling tower overflow rate should be checked frequently. If a tower is operated with insufficient overflow, the resulting mineral concentration in the water can cause rapid and heavy fouling inside the condenser tubes. This condition will necessitate frequent cleaning and could lead to severe corrosion. Chemical additives, including those to stop algae and related growths, should be obtained only from a reputable, established supplier, and use specifically according to directions. Excessive treatment of the water can cause more harm than none at all. Pumps, piping, and the tower any damaged in addition to the condenser. Double check the system to make sure that fouling is actually causing the trouble. High head pressure alone does not mean a fouled condenser. The following possibilities should always be checked before cleaning is undertaken. 1. Refrigerant overcharge. 2. Air in system or faulty head pressure gauge; (check standby pressures against refrigerant tables) 3. Incorrectly set, or defective, water regulating valve; (check its setting) 4. High water temperatures entering condenser; (check tower fan and system)
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Trouble Shooting PROBLEM
Lack of Cooling Effect
POSSIBLE CAUSE 1. Faulty compressor or lack of compression. 2. Temperature of air entering evaporator too high. 3. Fouled condenser and/or evaporator tube surface. 4. Low refrigerant charge. 5. Improper air flow through evaporator. 6. Room thermostat not operating properly. A. Due to Low Pressure Cut-out 1. Reduced air flow through evaporator. 2. Low refrigerant charge. 3. Restricted refrigerant line. 4. Faulty low-pressure cut-out or improper setting.
ACTION 1. Check discharge pressure for compression. Inspect compressor and replace if necessary. 2. Reduce load to design kW value. 3. Inspect surfaces and clean. 4. Repair refrigerant leak, add refrigerant. 5. Determine flow and adjust correctly belt tension. 6. Inspect thermostat and replace if necessary.
1. Inspect surface & clean, check evaporator fan drive. 2. Repair refrigerant leak, add refrigerant. 3. Determine the cause of restriction and repair. 4. Readjust or replace.
B. Due to High Pressure Cut-out
Tripping of Compressor(s)
1. Air in refrigerant system. 2. Excess refrigerant charge. 3. Faulty high-pressure cut-out or improper setting.
1. Re-evacuate refrigerant system and charge with new refrigerant. 2. Bleed off excess refrigerant. 3. Readjust or replace.
C. Due to Compressor Overload Protector tripping 1. Compressor over-current, under voltage or single phasing. 2. Excessive discharge pressure. 3. Compressor over-heating due to low refrigerant. 4. Compressor motor has a winding shorted. 5. Liquid refrigerant in compressor causing valve plate damage and lack of compression. 6. Defective overload protector. Excessive belt "scream" when fans start up Note:
1. Check electrical supply, contractors, wires and rectify fault. 2. See section B above. 3. Check refrigerant charge (fix leak), add if necessary. 4. Replace compressor. 5. Check that crankcase heater is functioning properly. 6. Replace protector.
1. Apply 'Grako Sprazon' belt dressing.
1. Slipping belts.
This condition service which should be attempted only by qualified service personnel. Contact your nearest McQuay service representative.
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REGISTERED S&E
ISO 9002
©2003 McQuay International
+1 (800) 432-1342
www.mcquay.com
