Discharge Temperature Controls; Inverter Frequency Control - York YMAA 0045 Installation Manual

Air-cooled chiller and heat pump 50hz 44-255kw

Table of Contents

FORM NO.: 6U6K-B01E-NB-EN

pressures detected are measured by gauge pressure. The ratio

must be kept in a certain range to make sure the compressor is

running within its envelope.

Compress ratio = (Pd+100) / (Ps+100);

Where:

Pd: Discharge gauge pressure, kPa;

Ps: Suction gauge pressure, kPa.

The ratio limitations are listed in Table 35 when loading is

prevented.

TABLE 35 - COMPRESS RATIO LOADING PREVENT-

ION LIMITATIONS

Fixed Speed SYS.

Inverter SYS.

TABLE 37 - COOLING DT LIMITATIONS

DT (°C)

DT<108°C

108≤DT≤111

111<DT≤115

DT>115

INVERTER FREQUENCY CONTROL

The frequency of the inverter compressor start-up, operation

and stop when rising speed and descending speed should be in

accordance with the figure below.

The compressor must be maintained on the stable platform (40

to 75 RPS, 50 as default) for at least 1 minute before load or

unload.

The frequency change rate of rising speed and descending

speed is 1 RPS (revolution per second).

JOHNSON CONTROLS

Cooke Industries - Phone: +64 9 579 2185

Cooling

Heating

6.2

6.6

7.8

Duration (s)

Normal operation

Load prevented

Unload 1Hz/5s

<30

Unload 2Hz/5s

Reduce to minimum frequency (40Hz)

≥30

Email: sales@cookeindustries.co.nz

SECTION 9 – UNIT OPERATION

The ratio limitations are listed in Table 36 when unload is

mandatory.

TABLE 36 - COMPRESS RATIO UNLOAD LIMITATIONS

Fixed Speed SYS.

Inverter SYS.