Marstair DCU+ 15 Installation Instruction Download Page 6

 

54208003-13 

 

 

 

 
 

Outdoor units are supplied with the following male flare connections  (in inches) :- 

 

 

 

 

NOTE:   Ensure  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. 

 
 

RESTRICTORS

 

 

Outdoor units (cool only & heat pumps) are supplied with expansion assemblies and cooling restrictors fitted. 

 

DCU+ 

10 

15 

20 

30 

40 

50 

60 

80 

Restrictor 

0.027 

0.032 

0.035 

0.037 

0.042 

0.046 

0.050 

0.058 

 
 

HEAT PUMP HEATING

 

 

All heat pump units have an additional expansion assembly supplied loose inside the unit. This is to be fitted 
to some indoor units for heating. Fit the assembly within 10m of the indoor unit in the expansion line. 

Note: 

the refrigerant flow is from indoor to outdoor, opposite to cooling assembly. Placing it directly at the 

indoor coil may cause increased noise during the heating cycle. No separate check valve is needed. The 
expansion assembly and line must be fully insulated. 

 

Note: 

The indoor units listed below are fitted with heating capillarys. 

WM60H, WM80H, WM100H, CC875/80H, CC875/110H, CC875/140H, HL380, HL460, HL540 
The additional heating expansion assembly (supplied loose in the heat pump unit) is not required. 
Retain as a spare. 

 

DHPUL 

15 

20 

30 

40 

50 

60 

Restrictor Cooling 

0.032 

0.037 

0.039 

0.043 

0.049 

0.052 

Restrictor Heating 

0.027 

0.036 

0.037 

0.042 

0.044 

0.053 

 

 

CONNECTING THE UNITS

 

 

1. 

Ensure both service valves on the unit are closed (clockwise) before 
commencing installation. 

 

2. 

If a expansion assembly requires cleaning: 

 

a.  Remove the entire expansion assembly from the outdoor unit. 
b.  Split the expansion assembly in the middle and remove the existing 

restrictor. 

c. 

Drop the new restrictor vertically into the field connector. 

d.  Reassemble in the vertical plane (field connector lowest) when 

reassembled the restrictor can be heard to be free to move if the 
assembly is shaken. 

e.  Refit the expansion assembly. 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

RESTRICTOR 

 
 

REFRIGERANT FLOW 

 

MODEL

 

DCU+

 

15

 

30

 

40

 

60

 

80

 

EXPANSION

 

3/8

 

3/8

 

3/8

 

3/8

 

1/2

 

SUCTION

 

3/8

 

1/2

 

1/2

 

5/8

 

5/8

 

 

MODEL

 

DHPUL

 

15

 

30

 

50

 

80

 

EXPANSION

 

3/8

 

3/8

 

3/8

 

1/2

 

SUCTION

 

3/8

 

1/2

 

5/8

 

5/8

 

 

PIPE CONNECTIONS / RESTRICTORS 

 

Summary of Contents for DCU+ 15

Page 1: ...g parts and refrigerant under pressure Always site out of reach of children and protect from vandalism 3 The units have fan speed control start delay timer HP and LP switches and a contactor fitted as...

Page 2: ...560 1174 490 65 65 240 392 865 404 81 DCU 60 1100 510 560 1174 490 65 65 240 392 865 404 81 DCU 80 1100 510 560 1174 490 65 65 240 392 865 404 84 DHPU L 15 930 510 495 1004 490 65 120 210 317 757 354...

Page 3: ...ers 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 provi...

Page 4: ...n thickness of at least 45mm is recommended 1 To maximise performance pipe runs should be kept as short as possible However individual pipe runs to a maximum of 80m 50m on sizes 15 20 including 20m li...

Page 5: ...Use the shortest possible route avoiding sharp bends 5 Fully insulate both the suction and expansion lines including the expansion device since both lines may sweat FITTING LOSSES in equivalent strai...

Page 6: ...check valve is needed The expansion assembly and line must be fully insulated Note The indoor units listed below are fitted with heating capillarys WM60H WM80H WM100H CC875 80H CC875 110H CC875 140H H...

Page 7: ...le charge to a sweat line on the evaporator Typical suction pressures on short lines at UK conditions with maximum evaporator and condenser fan speeds i e during commissioning will be 55 60 psig Take...

Page 8: ...t to suit the refrigerant It may be necessary to adjust this to suit site conditions to raise or lower the nominal head pressure a With the system switched off connect a high pressure gauge to the liq...

Page 9: ...hanges per turn of adjusting screw Pressure change 1 4 0 12 5 bar Clockwise 1 2 bar counter clockwise 1 2 bar Pressure change 2 9 2 21 2 bar Clockwise 2 5 bar counter clockwise 2 5 bar Pressure change...

Page 10: ...hed cables ElectromechanicalSystems Systems including an electromechanical indoor unit require a supply to the condensing unit with connecting cables run to the indoor unit Electronic Systems It is re...

Page 11: ...400V 3 50Hz disjoncteur a fournir 400 3 N 50 abgesicherts versorgung 400V 3 50Hz S S 1 3 7 S S Signal Ansteurung 230V 50Hz 1 3 7 S S SIGNAL 1 230V 50Hz 7 POWER TO SUIT SUPPLY FUSE PUISSANCE FOURNIR U...

Page 12: ...characteristics that allow starting of the compressor yet still afford close overcurrent protection under running conditions The ratings shown are for HRC motor rated fuses DUCTED UNITS DCU 15 DCU 20...

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