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Form 201.28-NM1.1
Issue date: 08/06/2021
4 in. / 6 in. / 8 in. flange
Figure 13 - Flange for GB vessels
Option flanges
One of two types of flanges may be fitted depending
on the customer or local pressure vessel code require-
ments. These are grooved adapter flanges, normally
supplied loose, or weld flanges, which may be supplied
loose or ready-fitted. Grooved adapter and weld flange
dimensions are to ISO 7005 - NP10.
Weld flange
Grooved adapter
Figure 14 - Flange attachment
Refrigerant relief valve piping
The evaporator is protected against internal refrigerant
overpressure by refrigerant relief valves. A pressure re-
lief valve is mounted on each of the main refrigerant
lines connecting the evaporator to the compressors.
A piece of pipe is fitted to each valve and directed so
that when the valve is activated the release of high
pressure gas and liquid cannot be a danger or cause
injury. For indoor installations (not recommended),
pressure relief valves should be piped to the exterior
of the building.
JOHNSON CONTROLS
The size of any piping attached to a relief valve must
be of sufficient diameter so as not to cause resistance to
the operation of the valve. Unless otherwise specified
by local regulations. Internal diameter depends on the
length of pipe required and is given by the following
formula:
D
= 1.447 x L
5
Where:
• D = minimum pipe internal diameter in cm
• L = length of pipe in meters
If relief piping is common to more than one valve, its
cross-sectional area must be at least the total required
by each valve. Valve types should not be mixed on a
common pipe. Precautions should be taken to ensure
the outlets of relief valves or relief valve vent pipes
LD10495
remain clear of obstructions at all times.
Electrical connection
The following connection recommendations are in-
tended to ensure safe and satisfactory operation of the
unit. Failure to follow these recommendations could
cause harm to persons or damage the unit, and may
invalidate the warranty.
SECTION 4 - INSTALLATION
10 in. flange
LD16185a
No additional controls (relays, and so on)
should be mounted in the control panel.
Power and control wiring not connected
to the control panel should not be run
through the control panel. If these pre-
cautions are not followed it could lead to
a risk of electrocution. In addition, elec-
trical noise could cause malfunctions or
damage the unit and its controls.
4
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