Interconnecting Wiring - Marstair WM Technical Manual

INTERCONNECTING WIRING

Interconnecting wiring diagrams are shown on pages 38 to 40.
WM E SYSTEMS:
C Hard wired to a handset (1 data cable)
• Fitted with a remote temperature sensor (1 data cable)
• A heat pump (1 data cable)
C BMS controlled (2 data cables)
C Networked (2 data cables)
Details of the kit are on page 46.
WM E MATCHED WITH EITHER MHPUE, OR DCUE
It is recommended that these systems should have a supply taken to the outdoor / ducted unit AND a separate supply
taken to the indoor unit, which in many cases can be from a domestic 13/16 Amp socket (see fuse tables page 10).
Communication cables should be screened 2 core (max. 0.75mm
clamps provided.
DO NOT use coaxial or mineral insulated cables.
ALL OTHER SYSTEMS:
Cables should be run to the outdoor unit with interconnecting cables run back to the indoor unit.
OUTDOOR UNIT WIRING
Cable entry for the outdoor unit electrics is through the cabinet to a terminal block.
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.
MCU+, MHPUE, DCUE and DHPUE are supplied wired to the high speed fan tapping via the head pressure controller
to give maximum control. Ensure that all connections are secure and that both units are earthed.
3Ph COMPRESSOR ROTATION
On 3 Ph units it is possible for the 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.
To reverse the rotation, switch off the mains power, identify the phase supplying the indoor unit, and exchange the other
two incoming supply phases
CAUTION: if one of the phases changed is the phase supplying the indoor unit, damage will occur.
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
Electromechanical models: In order to automatically switch off the fan in the event of a fire, fit an external switch (240V,
3A, closed to run, volt free contact) between terminal block terminal 2 and the Marstair remote control terminal L.
This switch should be operated by the building's fire alarm or BMS system - see wiring diagram page 29.
Electronic models: 'L' units: see wiring diagram page 30; 'E' units: see wiring diagram page 31.
Remove the black wire from the bottom terminal of the fuse (between fuse and motor) and place in series an external
switch (240V, 3A, closed to run, volt-free contact). This switch should be operated by the fire alarm or BMS.
An EMC gland kit (part number 55200301) MUST be used if the system is:-
.
--o--o--O--O--O--o--o–
One termination gland can be used for up to 3 cables. Each
cable is four core screened cable, available from Marstair
in
100m
rolls, part number 00526077.
2
) non polarised, grounded at both ends using the
-22-