Marstair 537 series User manual

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TECHNICAL MANUAL
for IMPACT-L WALL MOUNTED
SPLIT SYSTEMS.
This manual provides technical and installation information for IMPACT-L WALL MOUNTED split systems comprising:
INDOOR UNIT 537 series IMPACT-L
MATCHED WITH 550 series MCU or MCU+ condensing units
551 series MHPUL heat pump units
542 series DCUE ducted condensing units.
INDEX PAGE
GENERAL Part numbers 2
Dimensions and weights 3 - 4
Unit features/accessories 4
SELECTION Unit combinations, performance data 5
Optional electric heating, airflows 6
Sound power and sound pressure levels 6 - 7
ELECTRICAL Electrical data, recommended fuse sizes 8 - 10
UNIT IMPACT-L, condensate removal, air deflection 11 - 12
INSTALLATION MCU(+)/MHPUL units and DCUE units 13 - 15
Pipework, restrictors 16 - 18
PCB configuration 19
Electrical connections 19
IMPACT-L remote controller mounting 20
Evacuating and charging 20 - 21
WIRING IMPACT-L units 22
DIAGRAMS MCU(+)/MHPUL 23 - 25
DCUE 25 - 26
Interconnection 27 - 31
OPERATION User maintenance 31
IMPACT-L remote controller operation 32
IMPACT-L Electric heaters 34
Condensate pump 36
FAULT All units 38
FINDING Displays, diagnostics 38
COMPONENT Exploded views of units with 40 - 42
IDENTIFICATION component identification
TEV Ltd.,
Armytage Road, Brighouse,
West Yorkshire. HD6 1QF, UK.
Tel: [phone]
Fax: [phone]
Email: [email protected] 53799174-07

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IMPACT-L WALL MOUNTED SPLIT SYSTEMS
The IMPACT-L WALL MOUNTEDrange of split systems comprises 537 series IMPACT-L wall mounted indoor units,
550 series condensing units and 551 series heat pump outdoor units, or 542 series electronic ducted condensing
units.
By choosing appropriate combinations, the installer can provide:
AIR CONDITIONERS with a cooling range of 1.65 - 9.9 kW,
or HEAT PUMP systems with a cooling range of 2.0 - 8.6 kW, and a heating range of 1.9 - 9.4 kW with an
outdoor temperature of minus 1°C
PART NUMBERS
537 Series IMPACT-L INDOOR UNITS
Electronic IMPACT 20L IMPACT 40L IMPACT 60L IMPACT 80L IMPACT 100L
Part Number 53700064 53700065 53700066 53700067 53700068
550 Series CONDENSING UNITS (MCU/MCU+)
MCU 1Ph
Recip MCU 15 MCU 30 MCU 40 MCU 3Ph Recip MCU 30 MCU 40
R407C 55022045 55022047 55022048 R407C 55022053 55022054
R22 55022151 55022153 55022154 R22 55022074 55022075
MCU 1Ph
Scroll MCU 60 MCU 80 MCU 90 MCU 3Ph Scroll MCU 60 MCU 80 MCU 90 MCU 100
R407C 55022050 55022051 55022052 R407C 55022056 55022057 55022058 55022059
R22 55022071 55022072 55022073 R22 55022077 55022078 55022079 55022080
MCU+ 1Ph
Recip MCU+ 15 MCU+ 30 MCU+ 40 MCU+ 3Ph Recip MCU+ 30 MCU+ 40
R407C 55022002 55022004 55022005 R407C 55022011 55022012
R22 55022155 55022157 55022158 R22 55022032 55022033
MCU+ 1Ph
Scroll MCU+ 60 MCU+ 80 MCU+ 90 MCU+ 3Ph Scroll MCU+ 60 MCU+ 80 MCU+ 90 MCU+ 100
R407C 55022007 55022008 55099009 R407C 55022014 55022015 55022016 55022017
R22 55022029 55022030 55022031 R22 55022035 55022036 55022037 55022038
551 Series HEAT PUMP UNITS (MHPUL)
MHPUL 1Ph
Recip MHPUL 15 MHPUL 30 MHPUL 3Ph Recip MHPUL 30
R407C 55122040 55122042 R407C 55122048
R22 55122080 55122082 R22 55122066
MHPUL 1Ph
Scroll MHPUL 50 MHPUL 80 MHPUL 90 MHPUL 3Ph Scroll MHPUL 50 MHPUL 80 MHPUL 90
R407C 55122044 55122046 55122047 R407C 55122050 55122052 55122053
R22 55122062 55122064 55122065 R22 55122068 55122070 55122071
542 Series DUCTED CONDENSING UNITS (DCUE)
Electronic DCUE 1Ph DCUE 15 DCUE 30 DCUE 40 DCUE 60 DCUE 80
R22 54200002 54200004 54200005 54200007 54200008
R407C 54200027 54200029 54200030 54200032 54200033
Electronic DCUE 3Ph -- DCUE 30 DCUE 40 DCUE 60 DCUE 80
R22 -- 54200015 54200016 54200018 54200019
R407C -- 54200035 54200036 54200038 54200039

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UNPACKED DIMENSIONS AND WEIGHTS
IMPACT INDOOR UNITS
Model IMPACT
20L 40L 60L 80L 100L
HEIGHT mm 490 490 490 490 490
WIDTH mm 550 850 1150 1450 1750
DEPTH mm 204 204 204 204 204
WEIGHT kg 14 20 24 30 34
CONDENSING UNITS
Model MCU(+) 15 MCU(+) 30 MCU(+) 40 MCU(+) 60 MCU(+) 80 MCU(+) 90 MCU(+) 100
HEIGHT* mm 620 620 620 720 720 820 820
WIDTH mm 900 900 900 1000 1000 1000 1000
DEPTH mm 300 300 300 300 300 350 350
WEIGHT
kg 1 Ph 45 48 53 65 66 76 --
3 Ph -- 48 53 63 64 73 81
*Includes 60mm for mounting feet.
HEAT PUMP OUTDOOR UNITS
Model MHPUL 15 MHPUL 30 MHPUL 50 MHPUL 80 MHPUL 90
HEIGHT* mm 620 620 720 820 820
WIDTH mm 900 900 1000 1000 1000
DEPTH* mm 300 300 300 350 350
WEIGHT
kg 1 Ph 47 50 64 75 77
3 Ph -- 50 62 72 75
*Includes 60mm for mounting feet.
DUCTED CONDENSING UNITS
Model DCUE 15 DCUE 30 DCUE 40 DCUE 60 DCUE 80
HEIGHT* mm 560 560 560 625 625
WIDTH mm 1075 1075 1075 1245 1245
DEPTH mm 565 565 565 565 565
WEIGHT kg 69 70 72 81 84
*Includes 60mm for DCUE and 115mm for DHPUE mounting feet.
PACKED DIMENSIONS AND WEIGHTS
IMPACT-L INDOOR UNITS
Model IMPACT
20L 40L 60L 80 L) 100 L
HEIGHT mm 616 616 616 616 616
WIDTH mm 720 1020 1320 1620 1920
DEPTH mm 290 290 290 290 290
WEIGHT kg 16 22 27 33 37
CONDENSING UNITS
Model MCU(+) 15 MCU(+) 30 MCU(+) 40 MCU(+) 60 MCU(+) 80 MCU(+) 90 MCU(+) 100
HEIGHT mm 620 620 620 720 720 820 820
WIDTH mm 980 980 980 1080 1080 1090 1090
DEPTH mm 340 340 340 340 340 390 390
WEIGH
T kg 1 Ph 47 50 55 67 68 78 --
3 Ph -- 50 55 65 66 75 83

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HEAT PUMP OUTDOOR UNITS
Model MHPUL 15 MHPUL 30 MHPUL 50 MHPUL 80 MHPUL 90
HEIGHT mm 620 620 720 820 820
WIDTH mm 980 980 1080 1090 1090
DEPTH mm 340 340 340 390 390
WEIGHT
kg 1 Ph 49 52 66 77 79
3 Ph -- 52 64 74 77
DUCTED CONDENSING UNITS
Model DCUE 15 DCUE 30 DCUE 40 DCUE 60 DCUE 80
HEIGHT mm 580 580 580 650 650
WIDTH mm 1090 1090 1090 1270 1270
DEPTH mm 610 610 610 610 610
WEIGHT kg 74 76 76 86 90
FEATURES / ACCESSORIES
INDOOR UNITS
IMPACT-L
Adjustable air deflectors STD
De-ice thermostat STD
Electric heating *
3 fan speeds STD
Remote infrared control STD
Programmable timer STD
Condensate pump *
Flame retardant material STD
Long life washable filter STD
High or low level mounting STD
Key: * = factory / site option. STD = standard. --- = not available
OUTDOOR/DUCTED UNITS
MCU MCU+ MHPUL DCUE
CSR hard start (1 phase) * * * *
PTC hard start (1 phase) * * * *
Fan speed head pressure control * STD STD STD
LP cutout Auto * STD STD STD
HP cutout auto (with manual backup) * * * STD
HP cutout auto --- STD STD ---
HP cutout manual * * *
Isolator * * --- ---
3 minute start time delay * STD STD STD
Wall mounting brackets * * * *
Contactor STD STD STD STD
Overload (standard on 3Ph) * * * *
MHPUL condensate drain --- --- * ---
Low ambient start --- --- --- STD
Ducting kits --- --- --- *
Volt free relay * * * ---
Key: * = site option. STD = standard. --- = not available

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PRODUCT SELECTION
Combinations of indoor unit and (ducted) condensing / heat pump unit can be chosen to give either air
conditioning or heat pump systems.
UNIT COMBINATIONS
Air Conditioning Systems Heat Pump Systems
IMPACT-L MCU(+) or DCUE IMPACT-L MCU(+) or DCUE IMPACT-L MHPUL unit
20 15 20 15
40 30 40 40 40 30
60 40 60 60 60 50
80 80 80 90* 80 80
100 90* 100 100* 100 90
* Ducted unit not available at this size
AIR CONDITIONER PERFORMANCE DATA (kW)
UK CONDITIONS
ROOM 21°C/15°C
AMBIENT 27°C/19°C
NEMA (EUROVENT)
ROOM 27°C/19°C
AMB 35°C/24°C
TROPICAL
ROOM 29°C/19°C
AMB 46°C/24°C
IMPACT-L +
MCU(+) or DCUE MIN SPEED EVAP MAX SPEED EVAP MAX SPEED EVAP MAX SPEED EVAP
TOTAL SHR SENS TOTAL SHR SENS TOTAL SHR SENS TOTAL SHR SENS
20L + 15 1.4 0.71 1.1 1.9 0.77 1.5 2.1 0.78 1.6 1.6 0.98 1.6
40L + 30 2.3 0.77 1.8 3.1 0.83 2.5 3.4 0.84 2.9 2.9 0.96 2.8
40L + 40 2.7 0.74 2.0 3.6 0.78 2.8 4.0 0.78 3.1 3.2 0.98 3.1
60L + 40 3.0 0.78 2.3 3.9 0.88 3.5 4.4 0.86 3.8 3.7 0.99 3.7
60L + 60 3.7 0.74 2.7 5.1 0.80 4.1 5.4 0.81 4.4 4.4 0.98 4.3
80L + 80 4.2 0.74 3.2 5.7 0.87 4.9 6.4 0.85 5.4 6.0 0.92 5.5
80L + 90* 5.2 0.71 3.7 6.5 0.83 5.4 8.1 0.76 6.2 7.3 0.87 6.4
100L + 90* 5.6 0.73 4.1 7.5 0.84 6.3 8.8 0.84 7.4 8.1 0.88 7.1
100L + 100* 6.5 0.73 4.8 9.3 0.77 7.2 9.9 0.76 7.5 8.7 0.87 7.6
* Ducted unit not available in this size
For MED speed duties, interpolate between MIN speed and MAX speed duties.
Rating conditions are to BS2852: Part 1: 1982: UK condition C; NEMA condition A; Tropical condition B.
HEAT PUMP PERFORMANCE DATA
a. Cooling, (MAX speed outdoor unit fan). (kW)
UK CONDITIONS NEMA (EUROVENT)
ROOM 21°C/15°C AMBIENT 27°C/19°C R27°C/19°C A35°C/24°C
MIN SPEED INDOOR FAN MAX SPEED INDOOR FAN MAX SPEED INDOOR FAN
IMPACT-L TOTAL SHR SENS TOTAL SHR SENS TOTAL SHR SENS
20L 1.2 0.75 0.9 1.7 0.81 1.4 2.0 0.78 1.6
40L 2.2 0.78 1.7 3.0 0.83 2.5 3.3 0.85 2.8
60L 3.5 0.72 2.6 4.8 0.82 3.9 5.3 0.81 4.3
80L 4.9 0.77 3.8 6.3 0.82 5.1 7.1 0.85 6.0
100L 6.1 0.73 4.4 7.9 0.79 6.3 8.6 0.83 7.2
b. Heating, (Room 20°C/12°C, outdoor unit fan at MAX speed) (kW)
HEATING OUTPUT AT 7°C AMBIENT HEATING OUTPUT AT -1°C AMBIENT
MAX SPEED INDOOR FAN MAX SPEED INDOOR FAN
IMPACT-L kW COP kW COP
20L 2.3 2.23 1.9 2.00
40L 4.0 2.78 3.1 2.30
60L 5.4 2.60 4.3 2.20
80L 8.7 2.90 7.2 2.70
100L 11.2 3.02 9.4 2.93

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OPTIONAL ELECTRIC HEATING
at 230V 50Hz at 240V 50Hz
IMPACT-L (kW) (kW)
20L 0.7 0.8
40L 1.4 1.5
60L 2.1 2.25
80L 2.75 3.0
100L 3.2 3.5
AIRFLOWS IMPACT UNITS
MIN Speed MED Speed MAX Speed
IMPACT-L CFM m3/s CFM m3/s CFM m3/s
20L 125 0.06 170 0.08 210 0.10
40L 275 0.13 345 0.16 420 0.20
60L 360 0.17 440 0.21 645 0.30
80L 465 0.22 695 0.33 905 0.43
100L 550 0.26 750 0.35 1110 0.52
AIRFLOWS OUTDOOR/DUCTED UNITS
MIN Speed MAX Speed Min. Speed Max. Speed
Model CFM m3/s CFM m3/s Model CFM m3/s CFM m3/s
MCU(+) 15 MHPUL 15 1200 0.57 1720 0.81 DCUE 15 680 0.31 930 0.44
MCU(+) 30 - 1200 0.57 1720 0.81 DCUE 30 685 0.32 885 0.42
MCU(+) 40 MHPUL 30 1080 0.51 1530 0.72 DCUE 40 680 0.31 800 0.38
- - ---- - 8850.421115 0.53
MCU(+) 60 MHPUL 50 1250 0.59 1660 0.78 DCUE 60 885 0.42 1115 0.53
MCU(+) 80 - 1250 0.59 1660 0.78 DCUE 80 740 0.34 1040 0.48
MCU(+) 90 MHPUL 80 1440 0.68 2420 1.14 - ----
MCU(+) 100 MHPUL 90 1440 0.68 2420 1.14 - ----
SOUND POWER and SOUND PRESSURE LEVELS
537 SERIES IMPACT-L
SOUND POWER LEVELS SOUND PRESSURE LEVELS
Frequency Hz
MODEL SPEED 125 250 500 1K 2K 4K dBA dBA NC
20L Min 42.1 48.6 52.2 47.4 40.7 34.8 52.1 31.6 26 Med 45.5 51.3 54.6 51.8 45.3 39.1 55.6 35.1 30
Max 48.3 53.9 57.2 55.2 48.8 42.9 58.7 38.2 33
40L Min 45.9 51.4 53.3 51.3 46.9 44.6 55.6 35.1 30 Med 47.5 53.1 55.4 53.5 48.9 45.8 57.6 37.1 32
Max 50.7 55.6 58.0 56.6 51.9 48.0 60.4 39.9 35
60L Min 56.4 51.1 52.8 50.2 47.2 42.4 55.2 34.7 27 Med 56.6 53.0 55.4 52.9 48.6 43.6 57.3 36.8 31
Max 58.0 57.8 60.3 58.9 53.7 48.9 62.6 42.1 37
80L Min 46.5 49.5 51.2 47.6 41.4 34.3 51.9 31.4 25 Med 48.2 50.6 52.6 49.1 43.2 35.7 53.3 32.8 26
Max 53.4 57.5 60.0 58.3 53.0 47.6 62.0 41.5 36
100L Min 43.3 47.5 46.8 44.7 40.5 38.3 49.7 29.2 22 Med 48.6 51.1 52.3 49.7 43.6 39.4 53.8 33.3 27
Max 54.9 59.9 62.6 61.5 56.2 52.0 65.1 44.6 40
SoundPowerLevelswere obtainedin full conformitywithBS 4196:Part5: 1981.Quantitiesare shownin dBwith astandard
reference of 1 pW.
Sound Pressure Levels are dB relative to 2 x 10-5N/m2and are calculated from the results under anechoic conditions and
are quoted as an average of all points on a hemisphere of a radius of 3m away from the centre of the unit.

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SOUND POWER and SOUND PRESSURE LEVELS
550/551 SERIES MCU, MCU+ and MHPUL
MAXIMUM SPEED SOUND POWER LEVELS SOUND PRESSURE
LEVELS
Frequency Hz
MCU(+) MHPUL Compressor 125 250 500 1K 2K 4K dBA dBA NC
15 15 Recip 77.2 67.3 68.7 64.7 60.0 53.9 69.7 49.2 44
30 30 Recip 77.4 67.5 68.5 64.8 60.2 53.8 69.8 50.0 44
40 -- Recip 77.3 67.4 68.6 64.7 60.1 53.9 69.8 49.3 44
-- 50 Scroll 73.6 68.2 67.1 65.5 61.1 54.3 69.7 49.2 44
60 -- Scroll 72.9 67.7 67.8 66.4 61.9 54.1 70.3 49.8 45
80 -- Scroll 70.9 68.6 68.1 65.3 59.5 53.8 69.7 49.2 43
-- 80 Scroll 75.4 72.9 69.1 68.8 62.6 56.6 72.4 51.9 47
90 90 Scroll 81.8 71.8 69.2 68.6 63.1 57.4 72.8 52.3 47
100 -- Scroll 79.4 73.7 71.5 68.5 63.8 58.1 73.4 52.9 47
MINIMUM SPEED SOUND POWER LEVELS SOUND PRESSURE
LEVELS
Frequency Hz
MCU(+) MHPUL Compressor 125 250 500 1K 2K 4K dBA dBA NC
15 15 Recip 65.4 61.7 65.2 58.4 53.1 47.7 64.4 43.9 40
30 30 Recip 65.6 61.3 65.0 58.5 53.3 47.6 64.5 43.7 40
40 -- Recip 65.5 61.2 65.1 58.4 53.2 47.7 64.5 43.7 40
-- 50 Scroll 67.4 64.1 66.0 63.6 58.7 51.8 67.7 47.2 42
60 -- Scroll 67.4 64.3 67.1 66.8 60.7 51.7 69.7 49.2 45
80 -- Scroll 69.4 66.5 66.9 62.1 56.1 51.6 67.5 47.0 41
-- 80 Scroll 67.5 63.4 64.4 64.2 57.4 51.0 67.0 46.5 43
90 90 Scroll 79.0 65.4 64.9 61.5 58.5 53.7 67.6 47.1 40
100 -- Scroll 75.3 69.4 70.9 63.7 59.7 53.6 70.4 49.9 46
Sound Power Levels were obtained in full accordance with the direct method of ISO 3741: 1988. Quantities are shown in
dB with a standard reference of 1 pW.
Sound Pressure Levels are dB relative to 2 x 10-5N/m2and are calculated from the results under anechoic conditions and
are quoted as an average of all points on a sphere of a radius of 3m awayfrom the centre of the unit (in cooling mode); (add
3dBA or 3NC for units at an intersection of a wall, add 1dBA or 1NC for high level wall mounted units).
SOUND PRESSURE LEVELS -- DUCTED CONDENSING UNITS AND DUCTED HEAT PUMP UNITS
Measurement
Point Unit Size Fan Speed dBA NC
3m from
unit in void
DCUE 15, 30, 40
DHPUE 15, 30 Max 52 46
Min 35 28
DCUE 60, 80
DHPUE 50 Max 54 48
Min 44 31
Office
area
DCUE 15, 30, 40
DHPUE 15, 30 Max 37 26
Min 30 15
DCUE 60, 80
DHPUE 50 Max 42 28
Min 32 17
3m from
discharge grille
DCUE 15, 30, 40
DHPUE 15, 30 Max 52 46
Min 34 27
DCUE 60, 80
DHPUE 50 Max 52 44
Min 40 28
All readings taken from a typical application of a unit suspended in a ceiling void complete with 5m of insulated ducting,
conditioning an office directly below. Sound Pressure Levels are dB relative to 2x10-5N/m2.

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ELECTRICAL DATA (Cooling Data rated at NEMA conditions)
(Heating Data rated at 20°C/12°C indoor; 7°C/6°C ambient)
a) R22 Air Conditioning Systems (with MCU/MCU+)
Single Phase Supply 230Volts - 50Hz Three Phase Supply 400Volts - 50Hz
MODEL INPUT FULL LOAD AMPS SYSTEM
MAX.
STARTING
CURRENT
INPUT FULL LOAD AMPS SYSTEM
MAX.
STARTING
CURRENT
COMBINATION Cooling Heating Cooling Heating Cooling Heating Cooling Heating
IMPACT + MCU(+) kW kW AMPS AMPS AMPS kW kW A/PH A/PH* A/PH
20L + 15 0.9 0.9 4.3 3.7 22 -- -- -- -- --
40L + 30 1.2 1.7 6.2 7.3 33 1.7 1.7 4.2 7.3 19
40L + 40 1.4 1.7 7.3 7.3 33 2.1 1.7 5.4 7.3 23
60L + 40 1.4 2.5 7.4 10.8 33 2.1 2.5 5.5 10.8 23
60L + 60 2.3 2.5 10.3 10.8 62 2.3 2.5 4.5 10.8 33
80L + 80 2.9 3.3 11.4 14.4 77 2.9 3.3 4.9 14.4 41
80L + 90 4.0 3.3 16.6 14.4 116 4.0 3.3 7.4 14.4 50
100L + 90 4.0 3.4 16.8 14.4 116 4.0 3.4 7.6 14.4 50
100L + 100 -- -- -- -- -- 4.1 3.4 7.7 14.4 53
b) R22 Air Conditioning Systems (with DCUE)
Single Phase Supply 230Volts - 50Hz Three Phase Supply 400Volts - 50Hz
MODEL INPUT FULL LOAD AMPS SYSTEM
MAX.
STARTING
CURRENT
INPUT FULL LOAD AMPS SYSTEM
MAX.
STARTING
CURRENT
COMBINATION Cooling Heating Cooling Heating Cooling Heating Cooling Heating
IMPACT + DCUE kW kW AMPS AMPS AMPS kW kW A/PH A/PH* A/PH
20L + 15 1.3 0.9 6.0 4.0 25 -- -- -- -- --
40L + 30 1.8 1.7 8.4 7.6 37 1.8 1.7 3.6 7.6 19
40L + 40 2.3 1.7 10.6 7.6 51 2.3 1.7 4.8 7.6 24
60L + 40 2.3 2.5 10.7 11.1 51 2.3 2.5 4.9 11.1 24
60L + 60 3.1 2.5 14.3 11.1 61 3.1 2.5 6.0 11.1 26
80L + 80 3.2 3.3 17.0 14.7 72 3.2 3.3 7.0 14.7 26
c) R22 Heat Pump Systems (with MHPUL)
Single Phase Supply 230Volts - 50Hz Three Phase Supply 400Volts - 50Hz
MODEL INPUT FULL LOAD AMPS SYSTEM
MAX.
STARTING
CURRENT
INPUT FULL LOAD AMPS SYSTEM
MAX.
STARTING
CURRENT
COMBINATION STD.
MODEL + ELECT Heating STD. MODEL + ELECT Heating STD. MODEL + ELECT Heating STD. MODEL + ELECT Heating
IMPACT + MHPUL kW kW AMPS AMPS AMPS kW kW A/PH A/PH* A/PH
20(E) + 15 0.9 1.7 4.3 7.8 29 -- -- -- -- --
40(E) + 30 1.2 2.8 6.2 13.2 39 1.5 2.8 4.2 11.2 26
60(E) + 50 2.0 4.4 9.1 19.5 43 2.0 4.4 4.4 14.8 33
80(E) + 80 2.9 6.1 11.4 25.4 91 2.9 6.1 4.9 18.9 55
100(E) + 90 4.0 7.0 16.8 30.8 130 4.0 7.0 7.6 21.6 64
* Max. Phase.
d) R407C Air Conditioning Systems (with MCU/MCU+)
Single Phase Supply 230Volts - 50Hz Three Phase Supply 400Volts - 50Hz
MODEL INPUT FULL LOAD AMPS SYSTEM
MAX.
STARTING
CURRENT
INPUT FULL LOAD AMPS SYSTEM
MAX.
STARTING
CURRENT
COMBINATION Cooling Heating Cooling Heating Cooling Heating Cooling Heating
IMPACT + MCU(+) kW kW AMPS AMPS AMPS kW kW A/PH A/PH* A/PH
20L + 15 0.9 0.9 6.4 4.0 23 -- -- -- -- --
40L + 30 1.4 1.7 8.7 7.6 37 1.4 1.7 4.5 7.6 19
40L + 40 1.6 1.7 10.8 7.6 51 1.6 1.7 5.7 7.6 23
60L + 40 1.6 2.5 10.9 11.1 51 1.6 2.5 5.8 11.1 23
60L + 60 2.5 2.5 10.2 10.8 62 2.5 2.5 4.6 10.8 33
80L + 80 3.1 3.3 11.9 14.4 77 3.1 3.3 5.3 14.4 41
80L + 90 4.2 3.3 17.3 14.4 116 4.2 3.3 7.5 14.4 50
100L + 90 4.2 3.4 17.5 14.4 116 4.2 3.4 7.7 14.4 50
100L + 100 -- -- -- -- -- 4.4 3.4 7.8 14.4 53

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e) R407C Air Conditioning Systems (with DCUE)
Single Phase Supply 230Volts - 50Hz Three Phase Supply 400Volts - 50Hz
MODEL INPUT FULL LOAD AMPS SYSTEM
MAX.
STARTING
CURRENT
INPUT FULL LOAD AMPS SYSTEM
MAX.
STARTING
CURRENT
COMBINATION Cooling Heating Cooling Heating Cooling Heating Cooling Heating
IMPACT + DCUE kW kW AMPS AMPS AMPS kW kW A/PH A/PH* A/PH
20L + 15 1.3 0.9 6.0 4.0 25 -- -- -- -- --
40L + 30 1.8 1.7 8.4 7.6 37 1.8 1.7 3.6 7.6 19
40L + 40 2.3 1.7 10.6 7.6 51 2.3 1.7 4.8 7.6 24
60L + 40 2.3 2.5 10.7 11.1 51 2.3 2.5 4.9 11.1 24
60L + 60 3.1 2.5 14.3 11.1 61 3.1 2.5 6.0 11.1 26
80L + 80 3.2 3.3 17.0 14.7 72 3.2 3.3 7.0 14.7 26
f) R407C Heat Pump Systems (with MHPUL)
Single Phase Supply 230Volts - 50Hz Three Phase Supply 400Volts - 50Hz
MODEL INPUT FULL LOAD AMPS SYSTEM
MAX.
STARTING
CURRENT
INPUT FULL LOAD AMPS SYSTEM
MAX.
STARTING
CURRENT
COMBINATION STD.
MODEL + ELECT Heating STD. MODEL + ELECT Heating STD. MODEL + ELECT Heating STD. MODEL + ELECT Heating
IMPACT + MHPUE kW kW AMPS AMPS AMPS kW kW A/PH A/PH* A/PH
20L + 15 0.9 1.7 6.4 9.9 31 -- -- -- -- --
40L + 30 1.4 3.0 8.7 15.7 42 1.4 3.0 4.5 11.5 26
60L + 50 2.1 4.5 9.5 19.9 61 2.1 4.5 4.6 15.0 33
80L + 80 3.1 6.3 11.9 25.9 91 3.1 6.3 5.3 19.3 55
100L + 90 4.2 7.2 17.5 31.5 130 4.2 7.2 7.7 21.7 64
* Max. Phase.
ELECTRICAL LOADS (230V / 50 Hz / 1Ph) (A) or (400V / 50 Hz / 3PhN) (A/Ph)
IMPACT 20L 40L 60L 80L 100L
FAN MOTOR 0.2 0.3 0.4 0.4 0.6
ELECTRIC HEATER (AIR COND.) 3.5 7 10.4 14 14
ELECTRIC HEATER (HEAT PUMPS) 3.5 7 10.4 14 14
MCU(+) 15 30 40 60 80 90 100
FAN MOTOR 0.6 0.6 0.6 0.6 0.6 1 1
R407C COMPRESSOR (1 PH) NOMINAL FLA 5 7.2 9.3 9.2 10.9 15.9 --
R407C COMPRESSOR (3 PH) NOMINAL FLA -- 2.7 3.9 3.6 4.3 6.1 6.2
R22 COMPRESSOR (1 PH) NOMINAL FLA 3.5 5.3 6.4 9.3 10.4 15.2 --
R22 COMPRESSOR (3 PH) NOMINAL FLA -- 2.7 3.9 3.5 3.9 6 6.1
MHPUL 1530508090
FAN MOTOR 0.6 0.6 0.6 1 1
R407C COMPRESSOR (1 PH) NOMINAL FLA 5 7.2 8.3 10.9 15.9
R407C COMPRESSOR (3 PH) NOMINAL FLA -- 2.7 3.9 4.3 6.1
R22 COMPRESSOR (1 PH) NOMINAL FLA 3.5 5.3 7.9 10.4 15.2
R22 COMPRESSOR (3 PH) NOMINAL FLA -- 2.7 3.4 3.9 6.1
DCUE 15 30 40 60 80
FAN MOTOR 2.6 2.6 2.6 2.6 2.6
CRANKCASE HEATER 0.25 0.25 0.25 0.25 0.25
R407C COMPRESSOR (1 PH) NOMINAL FLA 5 7.2 8.3 12 14.1
R407C COMPRESSOR (3 PH) NOMINAL FLA -- 2.7 3.9 4.2 4.8
R22 COMPRESSOR (1 PH) NOMINAL FLA 3.5 5.3 6.4 12 14.1
R22 COMPRESSOR (3 PH) NOMINAL FLA -- 2.7 3.9 4.2 4.8

-10-
FUSES
The system and its supply/interconnecting wiring must be protected by fuses, preferably High Rupture Current
(HRC) motor rated types (EN60269) or miniature circuit breakers (EN60898) or local codes having similar time
lag characteristics, that allow starting of the compressor yet still afford close overcurrent protection under
running conditions. The ratings below are for HRC motor rated fuses.
FUSES FOR SYSTEMS WITH SINGLE PHASE (230 volt) OUTDOOR UNITS (A)
IMPACT-L
MCU(+) or
DCUE 20 40 60 80 100
SHSHSHSHSH
15 16 (10) 16
30 16 16
40 20 (16) 16 (20) 16 (20) 20 (16)
60 20 20 (16)
80 25 (20) 25 (20)
90* 32 32 32 32
MHPUE or
DHPUE SHSHSHSHSH
30 10 16
50 16 20
80* 25 (20) 32
90* 32 32
* Ducted unit not available in this size S= Standard H= Heaters
Figures in brackets are for R22 systems, if different to R407C fuses.
FUSES FOR SYSTEMS WITH THREE PHASE (400 volt) OUTDOOR UNITS (A/Ph)
IMPACT-L
MCU(+) or
DCUE 40 60 80 100
SHSHSHSH
30 10 10
40 10 10 16 (10) 16
60 10 16
80 10 16
90* 16 16 16 16
100* 16 16
MHPULSHSHSHSH
30 10 16
50 10 16
80* 10 20
90* 16 32
* Ducted unit not available in this size S= Standard H= Heaters
Figures in brackets are for R22 systems, where different to R407C fuses.

-11-
IMPACT-L WALL MOUNTED UNIT INSTALLATION
The IMPACT-L wall mounted unit may be matched with an outdoor condensing unit (550 series), a ducted condensing unit
(542 series), or a heat pump outdoor unit (551 series).
The installer supplies:
* 4 off M6 (or equivalent strength) Rawlbolt shields, bolts and washers.
* Fully insulated refrigeration pipework.
* All mains wiring with suitable isolation; Interconnecting wires for indoor and outdoor units.
* Condensate drain (minimum 10mm bore for gravity drain, 8mm bore for condensate pump drain).
* Two spanners for securing the flare connectors.
* A cross-headed screwdriver for releasing the end cover fasteners.
* A 4 or 5mm Allen key for opening the outdoor/ducted unit valves (depending on valve type).
* Method for securing solid sheathed cables if these are used.
Unpacking
Carefully unfasten the banding and lift off the outer cardboard carton sleeve.
The following are supplied:
* IMPACT-L unit (in protective sleeve, held between two polystyrene end caps).
* Acardboardsleeve containingtwopipeassembliescomplete withinsulation and twocable glandssuitable
for flexible, p.v.c. sheathed cable.
* A wall mounting bracket also held between the two polystyrene end caps.
* Envelope containing operating instructions to be left with the end user.
Infrared controller, wall mounting bracket, screws and two 1.5V AAA batteries.
1. Remove and place to one side the cardboard sleeve containing the two pipe assemblies, (and remote control
assembly on IMPACT-L models).
2. Lift the IMPACT-L unit from the inner cardboard sleeve complete with the two polystyrene end caps; (this will require
2 people for sizes 60 to 100).
3. Remove the wall mounting bracket and carefully remove the two polystyrene end caps
and the protective sleeve from the IMPACT-L unit.
4. Remove both end covers by removing the self tapping screws, one on each end trim.
By pulling the end covers sharplythey can be removed from the backpaneland fascia.
Chassis Mounting
NOTE: It is generally easier to fit kits prior to mounting the unit and connecting the pipework.
It is essential to fit a heater kit at this stage if right hand side access will be limited
to less than the unit width.
1. Ensure that the wall is flat and will support the operating weight of the unit, (see below)
2. Ensure that sufficient access is left around the unit for future kit fitting, servicing and maintenance (Fig. 1).
Model Weight
kg
Operating
Weight
kg
20L 14 15
40L 20 21
60L 24 25
80L 30 31
100L 34 35
*Includes all kits and refrigerant
*Removal or replacement of heater elements
requiresaclearanceattherighthandsideequal
to the length of the unit
Fig. 1.
3. Mark out the two required top hole centres as shown in Fig. 2, (note that the top of the IMPACT unit will be
approximately 100mm above the level of the hole centres). Drill to suit M6 Rawlbolt shields or equivalent
strength fasteners. Secure the wall mounting bracket to the upper two holes ensuring that it is level.
4. Hang the unit on the two protrusions from the wall mounting bracket and, ensuring that the unit is level, mark
out and drill the lower two holes and secure the unit to the wall.

-12-
Model 20L 40L 60L 80L 100L
A1 445 745 1045 1345 1645
A2 395 695 995 1295 1595
A3 345 645 945 1245 1545
B 370 370 370 370 370
C 340 340 340 340 340
D 3131313131
E 2929292929
Fig. 2.
Condensate Removal
Condensate collects in a drip tray along the full length of the coil.
An outlet pipe is provided at the rear left hand end of the tray for connection to a pipe for gravity drain.
Slide the outlet pipe from the clip and exit the unit vertically through the hole in the backpanel or base tray.
The drain stub has a 14mm o.d. barb and is supplied with connector and a short length of 6.35mm i.d. hose
For connection to a 10-12mm i.d. flexible hose, remove the hose and connector supplied and connect directly to
the stub.
Ensure that the drain pipe is kept below the rim of the drip tray along its entire length.
Oncea gravitydrain hasbeen installed,check toensurethat thepipe isnot kinkedand thatcorrectdrainage occurs
by slowly filling the drip tray with water.
A condensate pump kit (incorporating overflow protection) can be fitted within the unit to enable a lift of up to 5m.
Air Deflection
Air deflection is set by manually adjusting the vanes. The unit is supplied with front discharge but can be changed
to top discharge as follows.
1. Remove the filters.
2. Remove the end covers.
3. Using a screwdriver or thin bladed tool, release the three tabs at the bottom of the top box; these are
directly below the centre and two end vertical vanes.
4. Lift the top box assembly from the unit.
5. By gently flexing the top box
sides from the rear, transfer the
deflector plate from the upper to
the lower two fixing holes.
6. Rotate the top box assembly and
refit to give top discharge.

-13-
MOUNTING HOLES
INSTALLATION of 550 Series CONDENSING UNITS and 551 Series HEAT PUMP OUTDOOR
UNITS
MCU=standardcondensingunit MCU+=standard condensing unit + FSC + LP MHPUL = electronic heat pump outdoor unit
Some units are supplied with a number of loose restrictors which may be required, depending on the indoor unit
it is matched with and whether the unit is to be run in NEMA conditions; refer to pages 18 and 19.
The installer will require:
2 open ended spanners for securing the flare fittings
A 4 or 5mm Allen Key for the valves (dependant on valve type).
Note: It is easier to fit kits prior to mounting the unit.
These units are designed to stand on a flat surface. If the unit is to be
wall mounted the following kits are available.
(Marstair Ltd cannot accept liability for installers own mounting
arrangements).
Model MCU(+) 15 - 80 / MHPUL 15 - 60 MCU(+) 90 - 100 / MHPUL 80 - 90
Mounting Bracket Kit 55021100 55021101
Whether floor or wall mounted, it is essential that the mounting surface is capable of supporting the unit weight.
Leave space around the unit for air circulation and access for installation and maintenance.
MOUNTING:MCU(+) 15 - 100 and MHPUL 15 - 90
All dimensions are in millimetres.
MODELABCDEFGH
Weight (kg)
1 Ph 3 Ph
MCU(+) 15 900 300 560 525 185 60 295 275 45 --
MCU(+) 30 900 300 560 525 185 60 295 275 48 48
MCU(+) 40 900 300 560 525 185 60 295 275 53 53
MCU(+) 60 1000 300 660 570 213 60 295 275 65 63
MCU(+) 80 1000 300 660 570 213 60 295 275 66 64
MCU(+) 90 1000 350 760 495 250 70 345 325 76 73
MCU(+) 100 1000 350 760 495 250 70 345 325 -- 81
MHPUL 15 900 300 560 525 185 60 295 275 47 --
MHPUL 30 900 300 560 525 185 60 295 275 50 50
MHPUL 60 1000 300 660 570 213 60 295 275 68 66
MHPUL 80 1000 350 760 495 250 70 345 325 75 72
MHPUL 90 1000 350 760 495 250 70 345 325 77 75

-14-
DUCTED CONDENSING UNITS and DUCTED HEAT PUMP UNITS
Electronic fan speed control, start delay timer, HP and LP switches, stabilizing brackets and a contactor are fitted
as standard.
It is generally preferable to fit the following kits (if applicable), prior to mounting the unit. Kits available are:-
i) PTC (Positive Temperature Coefficient resistor). } for use on
single phase systems,
ii) CSR (Capacitor Start Relay). } particularly on long pipe runs.
iii) Isolator.
iv) Overload (single phase units only; standard on three phase units).
v) Wall mounting kit.
Consideration should be given to the following, prior to mounting, but should not be fitted until the unit is in
position:-
i) Flexible duct.
ii) Plenum (intake/discharge).
iii) Grille (intake/discharge).
MOUNTING
Units are supplied with a polystyrene packing piece supporting the blower assembly; this MUST be removed prior
to commissioning.
Ducted units are designed to be hung on a wall (kit available), suspended from a ceiling (installer supplied fittings),
or to stand on a flat surface. Whichever method is used, it is essential that the mounting surface is capable of
supporting the unit's weight.
DIMENSIONS
Model A B C D E F G H J K Spigot Ø Weight (kg)
DCUE 15 930 510 495 1004 490 65 65 210 317 717 354 69
DCUE 30 930 510 495 1004 490 65 65 210 317 717 354 70
DCUE 40 930 510 495 1004 490 65 65 210 317 717 354 72
DCUE 60 1100 510 560 1174 490 65 65 240 392 865 404 81
DCUE 80 1100 510 560 1174 490 65 65 240 392 865 404 84

-15-
FLOOR MOUNTING
Using the appropriate side of the packing carton as a template, (centres marked A), mark out and drill 4 holes
to suit maximum M8 bolts (also see overleaf). Secure the unit to the floor. Discard the stabilizing brackets.
Dimensions in mm.
Model A B
15 to 40 930 510
50 to 80 1100 510
SUSPENSION MOUNTING
The installer must supply 4 x M8 threaded rods with 16 nuts and washers to suit.
IMPORTANT: The stabilizing brackets provided MUST be used when suspending a unit.
Fit the stabilizing brackets to the top corners of the backpanel and front face using the No. 10
screws
provided, (2 per bracket).
If these brackets are omitted the unit will be subject to unacceptable movement on
compressor start
(Fig. 2).
Where long drops of M8 rod are used, it is advisable to incorporate flexible pipes in the suction and expansion
lines.
Using the template printed on the side of the packing carton, (centres marked A),
mark out theceilingand drill 4 holes to suit M8 screwed rod, (see Fig. 1).
Raise the unit to the required height and pass the screwed rods through the
mounting holes in the units feet and stabilizing brackets.
Secure the unit with a nut and washer on either side of each stabilizing bracket
and two nuts and washers underneath each foot mounting hole, (Fig. 2).
Fig. 2.
WALL MOUNTING
Wall mounting brackets are available as an optional kit (53200407).
DUCTWORK
Each unit is supplied with air inlet and discharge spigots:-
Models 15- 40: 354mm (14") Ø Models 50-80: 404mm (16") Ø.
These may be used for connecting installers ducting or with the optional duct, plenum and grille kits (refer to the
kit instruction for installation). The front face of the units are fitted with M6 rivnuts to accept square ducting (shown
below). Maximum flange width is 25mm and fixing holes should be central within them.
It is essential that inlet ducting is adequately insulated to prevent sweating,. An insulation thickness of at least
45mm is recommended.
Dimensions
(mm) Model
15 to 40 50 to 80
A 400 450
B 300 350
C 100 100

-16-
APPLICATION
1. To maximise performance, pipe runs should be kept as short as possible, avoiding sharp bends. However,
individual pipe runs to a maximum of 80m, , including 20m lift, are permissible provided good refrigeration
practice is followed.
Published performance duties are based on 7.5m pipe runs. Correctly sized pipes for each installation, and
fitting the correct expansion orifice (restrictor) will result in no significant loss of capacity on extended pipe
runs.
a) Pipe sizes are based on:-
Minimum of 3.8 m/s (750 fpm) suction gas velocity for horizontal or downflow.
Minimum of 7.6 m/s (1500 fpm) suction gas velocity for upflow.
Maximum of 15.2 m/s (3000 fpm) suction gas.
b) Where vertical risers exceed 3m, oil traps must be formed in the pipe. This will help ensure that oil
returns to the compressor. Typically fit an oil trap every 3m with a trap at the bottom of the riser.
2. Add 25 grams of polyolester (POE) oil for every 350 grams of charge added to systems with pipe runs
exceeding 25m, up to a maximum of 300 grams; preferably by slowly pumping into the suction side with the
unit running, after charging the system.
3. The maximum pipe lengths to be used for each pipe size and outdoor unit are shown in the table below. Use
of these sizes and lengths is recommended in order to achieve optimum system performance.
4. In calculating equivalent lengths of pipe runs, the effect of bends and fittings must be taken into account. The
tablebelow covers thefittings most likelyto beencountered inthis type ofinstallation. Theequivalentlengths
of all the fittings in a particular pipe run must be added together and the total added to the actual length of
pipe in the run, in order to calculate the total equivalent length.
FITTING LOSSES, in equivalent straight lengths of pipe (metres).
Pipe Size (outside diameter in inches)
Fitting 3/8 1/2 5/8 3/4 7/8 1-1/8
45° Bend 0.12 0.15 0.18 0.21 0.24 0.3
90° Bend R/d = 1 0.37 0.43 0.49 0.55 0.61 0.79
90° Bend R/d = 1.5 0.24 0.27 0.30 0.37 0.43 0.52
180° Bend C/d = 1.5 0.73 0.91 1.10 1.28 1.46 1.83
180° Bend C/d = 2.5 0.46 0.55 0.64 0.76 0.85 1.07
90° Elbow 0.67 0.85 1.04 1.25 1.46 1.89
R = Radius of bend d = Diameter of tube C = Centres of bend
5. Use the shortest possible route, avoiding sharp bends.
6. Fully insulate both the suction and expansion lines, including the expansion device, since both lines may
sweat.

-17-
RESTRICTORS
Outdoorunitsare suppliedwith coolingrestrictorsfittedin theexpansionassembly;refer tothefollowing tables
for any restrictor changes. Those ticked do not require a change of restrictor.
Heat pumps are supplied with a heating resrtrictor in an expansion assembly. This must be fitted close to the
indoor unit in the expansion line, arrows pointing in the direction of the outdoor unit.
Where appropriate, thealternative cooling or heating restrictor is supplied with either the indoor or the outdoor
unit.
SYSTEM
MATCH
PIPE CONNS MAXIMUM PIPE RUNS (m) COOLING RESTRICTOR R407C (R22)
CHARGE TO ADD
(for 7.5m)
SUCNEXPNSUCTION EXPANSION MCU(+) DCUE
UK NEMA UK +
NEMA UK (g) NEMA (g)
3/8 1/2 5/8 3/4 7/8 11/83/8 1/2 5/8
IMPACT 20L 3/8 3/8 7.5 30 50 50 033 035 032 210 (200) 240 (230)
MCU(+)15
DCU(+) 15 3/8 3/8
IMPACT 40L 1/2 3/8 15 50 80 50 80 040 042 039 0 (0) 60 (65)
MCU(+)30
DCU(+) 30 1/2 3/8
IMPACT 40L 1/2 3/8 10 36 80 7.5 80 042 044 041 140 (140) 245 (240)
MCU(+)40
DCU(+) 40 1/2 3/8
IMPACT 60L 5/8 3/8 10 36 80 7.5 80 042 044 043 200 (200) 305 (300)
MCU(+)40
DCU(+) 40 1/2 3/8
IMPACT 60L 5/8 3/8 14 36 80 7.5 50 80 051 053 050 0 (0) 670 (635)
MCU(+)60
DCU(+) 60 5/8 3/8
SYSTEM
MATCH
PIPE
CONNS MAXIMUM PIPE RUNS (m) COOLING
RESTRICTOR HEATING
RESTRICTOR
(WITH ODU)
R407C (R22)
CHARGE TO ADD
(for 7.5m)
SUCNEXPNSUCTION EXPAN-
SION MHPUL
MHPUL
UK NEMA UK
(g) NEMA (g)
3/8 1/2 5/8 3/4 7/8 3/8 1/2 5/8
IMPACT 20L 3/8 3/8 7.5 30 80 50 033 035 035 0 (0) 170 (180)
MHPUL 15 3/8 3/8
IMPACT 40L 1/2 3/8 15 50 80 50 80 040 042 039 0 (0) 160 (170)
MHPUL 30 1/2 3/8
IMPACT 60L 5/8 3/8 7.5 18 50 80 7.5 50 80 052 052 044 0 (0) 90 (100)
MHPUL 50 1/2 3/8
PIPE CONNECTIONS
IMPACT-L UNITS
Pipework is terminated at the left hand side of the unit. Two pipe assemblies are supplied loose
with flare nut connectors to enable pipe exit from either the top or bottom of the unit via
knockouts. Rear pipe exit is possible with installer supplied pipework.
Always use two spanners to secure the flare connections to avoid distorting and damaging the
pipework.
Pipe flare connections (in inches) are;
IMPACT Model 20L 40L 60L 80L 100L
Expansion Pipe 3/8 3/8 3/8 1/2 1/2
Suction Pipe 3/8 1/2 5/8 5/8 3/4
PIPEWORK CONNECTION and RESTRICTORS
1. If top or bottom pipe exit is required, remove the appropriate knockout in the backpanel flanges.
2. Remove and retain the flare nuts from the coil, (the bonnets should be discarded).
3. Screw the angled ends of the pipe extensions to the male connectors on the coil, ensuring that the straight
ends extend through the knockout.
For pipe exit through the rear of the unit, the installer must supply appropriately flared pipework.
On heat pump systems the IMPACT unit needs to have an expansion assembly fitted: refer to the next
section.

-18-
4. Interconnecting pipework should be installed in
accordance with good refrigeration practice.
5. Final connection is made to the male flare
connectors, eitheron the pipeextensions(for top
or bottom entry) or directly onto the coil (for rear
entry).
6. Care should be taken to ensure that pipe flares
are correctly formed and have undamaged
seating surfaces. The use of a little oil on the
flaring tool will help. DO NOT FORGET to fit the
flare nut onto the pipe BEFORE flaring it.
7. Make the flare connections to IMPACT-L using a
little refrigeration oil on the mating surfaces.
Always use two spanners in opposing directions
to avoid twisting the pipework and damaging the
coil connections.
OUTDOOR/DUCTED UNITS
1. Outdoor/ducted units are supplied with the
following male flare connections (sizes in inches);
Model
Size MCU(+) / DCUE MHPUL
15 30 40 60 80 90 100 15 30 50 80 90
Expansio 3/8 3/8 3/8 3/8 1/2 1/2 1/2 3/8 3/8 3/8 1/2 1/2
Suction 3/8 1/2 1/2 5/8 5/8 5/8 3/4 3/8 1/2 1/2 5/8 3/4
Ensure that both service valves on the outdoor unit are closed (IN, fully clockwise) before commencing
installation.
Indoor units have a low pressure holding charge of nitrogen, which may be released into the atmosphere
without damage to the environment. This should be done prior to making pipework connections.
2. Outdoor units are delivered with restrictors: see page 18 for details of any changes necessary.
3. MHPUL 15 - 90 are supplied with 2 expansion assemblies. One is fitted to the outdoor unit and one is supplied
loose to be fitted to the indoor unit. For any change of restrictor, reference must be made to the tables on
pages 18 and 19.
a. When installing a heat pump system, the second expansion assembly (140mm long) must be fitted tothe
expansion line as close to the indoor unit as possible. This provides throttling of the refrigerant and
eliminates the need for separate check valves.
b. Remove the flare nuts from the suction service valve and the expansion device as appropriate.
c. Ensure that both the suction and expansion lines are fully insulated.
d. Place the flare nuts over the incoming pipework and flare the pipe ends. The use of a little refrigeration
oil on the flaring tool will help.
e. Connect the pipework between the units. Do not leave pipe ends, valves etc. open to the atmosphere.
Always use two spanners when tightening the flare nuts to avoid twisting the pipes. Use a small amount
of refrigerant oil on the mating surfaces.
f. Sightglasses andfilterdriersare notnecessary,butif requiredshould befittedbetweenthe outdoorunit
liquid shut off valve and the expansion device.
4. For units supplied with an alternative restrictor, replace the restrictor in the
outdoor unit by:
a. Completely removing the expansion assembly from the outdoor unit.
b. Split the expansion assembly in the middle.
c. Remove the existing restrictor.
d. Drop the new restrictor vertically downwards into the field connector.
e. Reassemble in the vertical plane (field connector lowest) and refit the
expansion assembly to the outdoor unit.

-19-
ELECTRICAL CONNECTIONS
CONFIGURATION
HEAT PUMPS need to have a resistor removed from the external electrics box.
AIR CONDITIONERS need to have the pcba jumpers reconfigured.
HEAT PUMPS
Theprintedcircuitboardissuppliedconfiguredforheat
pump systems.
NO JUMPER RE-CONFIGURATION IS NECESSARY -
JUMPER IS FITTED TO JMODE or CNMODE.
INDOOR BOARD
(AS SUPPLIED SUITABLE FOR HEAT PUMP SYSTEMS)
THERESHOULDNOTBE ARESISTORCONNECTEDTO
THE TERMINALS MARKED 'S'
AIR CONDITIONERS
PRIOR TO CONNECTING A POWER SUPPLY
For use in an air conditioning system with or without an
electric heater fitted, reconfigure the printed circuit
board as follows:
1. LocateprogrammingplugJMODE orCNMODE inthe
middle of the printed circuit board.
2. Remove and discard programming plug JMODE or
CNMODE.
INDOOR BOARD
(RECONFIGURED FOR AIR CONDITIONING SYSTEMS)
THERESISTOR SHOULDREMAINCONNECTED TOTHE
TERMINALS MARKED 'S'
INCORRECT PROGRAMMING
If the unit has been powered whilst incorrectly programmed, turn the power OFF then ON again.
ALL SYSTEMS
Systems require a supply to the outdoor unit with connecting cables run to the indoor unit.
Refer to pages 27 to 31 for the interconnecting wiring diagrams.
Mains, control and interconnecting cables are supplied and fitted by the installer.
Installer wiring must be carried out in accordance with local and national codes.
Cables must be size compatible with the recommended fuse for a given system.
An isolator switch should be positioned within easy reach of the indoor unit.
The equipment MUST be earthed.

-20-
Cable clamps for use with stranded cables are supplied in units 15 - 90 and should be used to secure all
incoming/outgoing cables. Installers must supply a method of securing any solid sheathed cables.
OUTDOOR UNIT WIRING
Cable entry for the outdoor unit electrics is through the cabinet to a terminal block.
MCU+,MHPULandDCUEaresuppliedwired viatheheadpressurecontrollertogivemaximumcontrol.Ensure
that all connections are secure and that both units are earthed.
Electromechanical condensing units (MCU) are supplied wired for low fan speed, which is suitable for
temperate climates. If continuous running is expected at ambient temperatures of 35°C or higher, change to
high speed by interchanging the black and red wires, i.e. black to fused terminal, red to terminal 4 (single fan
units) or terminals 4 and 8 (double fan units).
COMPRESSOR ROTATION
On 3 Phase units sizes 50 to 100 it is possible for the scroll compressor to run backwards. This becomes
obvious on start up; the compressor will not develop a normal running pressure differential and the top will
not become warm. It may be excessively noisy. If this happens, switch off the mains power and exchange any
two of the phases supplying the unit. This will correct the rotation of the compressor.
DATA PLATES
Because of the ability to mix-match indoor and outdoor units, the data plate only gives information on outdoor
units. To obtain the system details, input power and currents from indoor and outdoor units should be added
together.
Data plates show basic units with electric heater kit loads shown separately.
FIRE LINK
In order to automatically switch off the fan in the event of a fire, it is necessary to fit an external switch (240V,
3A, closed to run, volt free contact) in series with the small black wire connected to the bottom terminal of the
fuse.
This switch should be operated by the building's fire alarm or BMS system.
IMPACT-L REMOTE CONTROLLER
IMPACT-L indoor units are supplied with a remote controller, wall mounting
bracket, two batteries, and screws: suitable wall plugs must be provided by the
installer.
The controller operates remotely by infrared signals and the bracket may be used
to park the controller for convenience.
Infrared operation
Slide down the cover at the front of the controller. Insert two AAA batteries,
(checking polarity), then close the cover.
The controller is now ready for operation, as shown on page 32 .
Avoid installing the unit at high level with the infra red receiver (display)
close to, and in direct line of sight of, fluorescent lamps as this may cause
false operations. If this should occur, reset by turning the power off for a
few seconds.
EVACUATING
1. Connect a vacuum pump to the service ports on the outdoor unit valves and evacuate the interconnecting
pipework and indoor unit to 1000 microns (1 Torr) or better and allow to be held for a minimum of 15 minutes.
2. If NO additional refrigerant charge is required:
Replace the caps on the service ports, (tighten to a torque of 25NM), and open the valves using a 4 or 5mm
Allen key. On electronic units, REMOVE link JP6 identified by a white label, (otherwise the unit will always run
at full speed).
ADDING REFRIGERANT
1. If additional refrigerant charge is required:
After evacuating the indoor unit and interconnecting pipework, open the valves using a 4 or 5mm Allen key.