Internal Pressure Relief Valve; Oil Differential Pressure Control; Maximum Allowable Pressures; Brazing Procedure - Emerson Copeland 2D Application Manuallines

maintenance work. The compressors may only be energized when the safety measures (high-
and low-pressure cut-outs and discharge temperature cut-out) have been checked and verified
to be operational.
NOTE: All of the above points must be fulfilled. If any of them cannot be met, the compressor
must not be operated below atmospheric pressure.

3.2.4 Internal pressure relief valve

8D* compressors are equipped with an internal pressure relief valve placed between the suction
chamber and the discharge chamber. The valve protects the compressor against bursting if the
discharge shut-off valve is accidentally fully closed.
NOTE: The valve will not protect the installation against dangerous system pressures!
Before operating the compressors, the pressure switches and other safety devices must be installed
correctly. The maximum allowable pressures must not be exceeded.
Each cylinder head has a plugged 1/8" – 27 NPTF tapped hole for connecting a high-pressure switch.

3.2.5 Oil differential pressure control

The oil pressure switch breaks the control circuit when the pressure difference between the oil pump
outlet and the crankcase is too low. If the oil differential pressure drops below the minimum
acceptable value the compressor will be stopped after a 120-second delay. After having solved the
problem the control has to be reset manually. The switch must be properly adjusted and tamper-
proof.
The following oil pressure switches can be delivered as accessories:
 Electronic oil pressure switch OPS2
 Mechanical oil pressure switch Alco Controls FD-113ZU, applicable only with A1 refrigerants
For more information on the oil pressure switches and wiring diagrams, see Section 4.7 "Oil
differential pressure control".
NOTE: Proper oil pressure safety control with an approved switch is a condition of warranty!

3.2.6 Maximum allowable pressures

The maximum allowable pressures according to EN 12693 are shown on the compressor nameplate.
They are obligatory and must not be exceeded.
High-pressure side (HP):

Low-pressure side (LP):

NOTE: The compressor operating range may be restricted for various reasons. Check the
application range limitations in Select software at www.climate.emerson.com/en-gb.
3.3

Brazing procedure

WARNING
Air/flammable refrigerant mixture! Creation of a potentially flammable
atmosphere! Fire hazard! Remove all refrigerant before opening the system.
When working on a refrigerant-filled system, make sure to follow the safety
and working instructions given in Chapter 6 "Maintenance & repair".
WARNING
High temperature! Burning! Proceed with caution when brazing system
components. Do not touch the compressor until it has cooled down. Ensure
that other materials in the area of the compressor do not come into contact
with it.
CAUTION
Blockage! Compressor breakdown! Maintain a flow of oxygen-free nitrogen
through the system at very low-pressure during brazing. Nitrogen displaces
the air and prevents the formation of copper oxides in the system. If allowed
to form, the copper oxide material can later be swept through the system and
block screens such as those protecting capillary tubes, thermal expansion
valves, and accumulator oil return orifices.
AGL_HA_ST_Discus_A2L_A1_EN_Rev00
32.5 bar (g)
22.5 bar (g)
13