Electrolux EHG 678 B Manual de usuario descargar pdf (Pagina 4)

135

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135

www.hidros.it

WDA

fans), compressor fuses, control circuit au-

tomatic breakers, compressor contactors,

fan contactors and pump contactors. The

terminal board has volt free contacts for

remote ON-OFF, Summer/Winter change

over (heat pumps only) and general alarm.

For all three phase units, a sequence relay

that disables the power supply in the event

that the phase sequence is incorrect (scroll

compressors can be damaged if they rotate

in the wrong direction), is ﬁtted as standard.

CONTROL AND PROTECTION DEVICES

All units are supplied with the following

control and protection devices: Return

water temperature sensor installed on the

return water line from the building (12°C),

antifreeze protection sensor installed on

the outlet water temperature (7°C), high

pressure switch with manual reset, low

pressure switch with automatic reset, high

pressure safety valve, compressor thermal

overload protection, fans thermal overload

protection and ﬂow switch.

CONDENSERLESS VERSIONS EV

This version includes a microprocessor

control to manage both the compressor ti-

MICROPROCESSORS

All WDA units are supplied as standard

with microprocessor controls. The micro-

processor controls the following functions:

control of the water temperature, antifreeze

protection, compressor timing, compressor

automatic starting sequence, alarm reset,

volt free contact for remote general alarm,

alarms and operation LED’s. If required

(available as an option), the microprocessor

can be conﬁgured in order for it to connect

to a site BMS system thus enabling remote

control and management. The Hidros tech-

nical department can discuss and evaluate,

in conjunction with the customer, solutions

using MODBUS protocols.

ELECTRICS ENCLOSURE

The enclosure is manufactured in order to

comply with the requirements of the elec-

tromagnetic compatibility standards CEE

73/23 and 89/336. Access to the enclosure

is achieved by removing the front panel of

the unit. The following components are sup-

plied as standard on all units: main switch,

thermal overloads (protection of pumps and

mings and alarms. It is designed to operate

with refrigerant R410a but is supplied with

a holding charge of nitrogen.

HEAT PUMP VERSIONS HP

The heat pump versions are provided with

a 4 way reversing valve and are designed

to produce hot water up to a temperature

of 50°C. They are always supplied with a

liquid receiver and a second thermostatic

valve in order to optimize the efﬁciency

of the refrigerant cycle in heating and in

cooling. The microprocessor controls de-

frost automatically (when operating in low

ambient conditions) and also the summer/

winter change over.

PARTIAL HEAT RECOVERY RP

This version is supplied with an auxiliary

heat exchanger ﬁtted in series with the unit

condenser thereby enabling it to produce

hot water when the unit is operating in co-

oling mode.

oil does not run back to the compressor

by gravity and that it continues to circu-

late in the correct direction. On horizontal

suction pipelines a minimum of 1% slope

in the direction of ﬂow should be provided

in order to ensure the oil ﬂow back to the

compressor. Required pipeline diameters

for various unit sizes and pipe run lengths

can be found in the following table.

Condensing unit installed at a lower

level than the evaporation section

Install a liquid trap on the suction line at

the evaporator outlet and at the same

height in order that liquid refrigerant,

when the system is off, will not fall back

to the compressor. Locate this trap down-

stream from the bulb of the thermostatic

valve to ensure that when the compressor

is restarted, the rapid evaporation of the

refrigerant liquid ﬂuid in the trap will not

affect the bulb of the thermostatic valve.

On horizontal suction pipelines a minimum

of 1% slope in the direction of ﬂow should

Condensing unit (WDR/EV) versions must

be connected to the indoor unit by refrige-

rant lines. The condensing units are sup-

plied without refrigerant charge but with a

holding charge of nitrogen.

Piping layout and max distance between

the sections.

On split-system applications, the piping la-

yout is determined by the location of the in-

door and outdoor units and by the building

structure. Pipe runs should be minimised

in order to reduce the pressure drops in

the refrigerant circuit and the refrigerant

charge required. The maximum allowa-

ble pipe length is 30 meters. Should your

requirements exceed the limits described

above, please contact our application en-

gineers who will be delighted to assist.

Condensing unit installed at a higher

level than the evaporation section

On the rising vertical pipes, oil traps should

be ﬁtted every 6 metres to ensure that the

be provided in order to ensure the oil ﬂow

back to the compressor.

The refrigerant line diameters are determi-

ned from the selected unit size and the di-

stance between the indoor and the outdoor

unit. The table below provides the recom-

mended sizes for various combinations.

CONDENSERLESS UNITS REFRIGERANT CONNECTIONS

1 2 3 4 5 6

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