J&E Hall JEHSD-0400-B3-M-3, Техническое руководство

Страница: 25 / 44

Issue: 01.08.2020 Page 25
Commissioning
Safety pressure switch settings (Mechanical)
The Saginomiya SNS low pressure switch fitted to the JEH Digital Scroll condensing unit has adjustable cut-out and differential.
High pressure protection is provided by a cartridge type high pressure switch (HP1) which has fixed settings.
High Pressure Safety
The high pressure safety switch is required to stop the compressor should the discharge pressure exceed the values shown in the
following table. The differential pressure is fixed at 6 bar (87 psi). Once tripped, it will create an alarm condition which requires
manual reset at the controller.
Refrigerant R407A/R407F/R448A/R449A
Cut Out / Cut In (bar g)
28 / 22
Cut Out / Cut In (psi g)
410 / 323
Low Pressure Safety
The adjustable low pressure safety switch provides compressor protection from low suction pressure/evaporating temperature in
Normal (controller) operation. In mechanical bypass mode, it provides compressor control. It also protects the compressor
against deep vacuum operation, a potential cause of failure due to internal arcing and overheating. The low pressure switch is
factory set as below. For Normal (controller) operation, please do not adjust this setting.
For operation in bypass mode, the low pressure control should be set to control the compressor (fixed speed only for twin
compressor) at the required SST according to the application.
If adjusted for operation in bypass mode, the low pressure control
must be reset to factory setting as below before returning to Normal (controller) operation.
Refrigerant R407A/ R407F/ R448A/ R449A
Application M*
Cut Out / Cut In (bar g) 1.0 / 3.0
Cut Out / Cut In (psi g) 15 / 44
AC Fan Speed Modulation Controller
The fan speed control is factory preset with a ±3.0barG differential setting. With this setting, the fan operation is as follows:
Refrigerant R407A/ R407F/ R448A/R449A
Fan Setpoint (bar g) 16
Fan start run (bar g)
13
Fan Full Speed (bar g) 19
The fan under FSC control will start at 100% speed for approximately 5 seconds before start modulates between 45% of full fan
speed and 100%.