J&E Hall JEHSD-0600-M-3, Техническое руководство

Страница: 21 / 40

Issue: 01.05.2017 Page 21
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
Cut Out / Cut In (bar g)
Cut Out / Cut In (psi g) R404A/R407A/R407F/R448A/R449A
28 / 22
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.
Unit
Refrigerant
Application
Cut Out / Cut In (bar g)
Cut Out / Cut In (psi g)
* M edium Temperature
JEHSD-0600-M-3
R404A/R407A/R407F/R448A/R449A
M*
1.0 / 3.0
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
Fan Setpoint (bar g)
Fan start run (bar g)
Fan Full Speed (bar g) R404A/R407A/R407F/R448A/R449A
16
13
19
The fan under FSC control starts at 45% of full fan speed and modulates up to 100%.