Johnson Controls RWF 1080 Operating Manual Download

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Operating manual- SAB 355 (including ATEX)

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004059 en 2019.11

Operating instructions

Warning!

On ATEX-executions, the limits in

Table 7

must always be respected.

Temp. class

Max. surface

temp.

Max. temperature of oil to

shaft seal

Min. ignition temperature

of oil

450°C

380°C

500°C

300°C

230°C

350°C

200°C

130°C

250°C

135°C

65°C

185°C

100°C

30°C

150°C

85°C

15°C

135°C

Table 7: Temperature classes - screw compressors

6.22

Initial start-up procedure

Only competent personnel with a thorough knowledge of refrigeration technique may start up the
unit. Prior to start-up, the prestart check must be accomplished.

Having performed the checkpoints on the

installation

and

Preparation before start checklists

, the

compressor unit is ready to start up. It is important that an adequate refrigerant load is available
to load test the unit at normal operating conditions.

Note:

During the initial start-up of the unit, it is imperative that the hand expansion valve on the

main oil injection line is fully open to ensure adequate oil flow. Using a demand oil pump it may be
necessary to throttle in order to half open valve before start-up.

There is an orifice installed in the compressor to control maximum oil flow. At initial start-up of
the compressor, the hand expansion valve must be fully open. After initial start-up of the unit, the
hand expansion valve must be adjusted unless the unit is equipped with a motorised oil injection
valve.

Motorised oil injection valve

Some units, usually if they have variable speed control (VSD), are equipped with a motorised
valve that controls the amount of oil being led to the rotors. This control uses the rotational speed
to set the appropriate opening degree of the valve and thereby regulate the amount of oil for the
rotor injection so that it follows the rpm of the compressor.

The motorised valve replaces the functionality of the hand expansion valve.

Note:

On units with both a motorised and a hand expansion valve on the oil injection inlet, the

hand expansion valve must be completely open unless otherwise agreed with the factory.

The factory settings of the motorised valve ensure that the valve is always minimum 5% open
during operation. The maximum opening degree must be adjusted according to the specific appli-
cation. The adjustment at first start-up is made via the Unisab III display - and not on the valve
motor’s control display (ICAD).

Correct setting at first start-up

: when the unit has achieved nominal operating conditions, ad-

just the parameter called Oil Flow Open Max. via the Unisab III display. Increase the value if the
discharge temperature is too warm and decrease it if the temperature is too cold. Once the value
has been set, it will not need to be changed again unless the compressor should run at completely
different operating conditions. To determine the desired discharge temperature, see the method
selection below.

Method selection

First method

The best method to determine the target discharge temperature is to run Coolware/Comp1. Run
Coolware/Comp1 or ScrewSelect with the operating conditions of the compressor. The program