Engineered air EngA CU Series, Инструкция по установке, эксплуатации и обслуживанию

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CU MANUAL
IOM-14 15 of 46 Feb 06 R4
Liquid Receivers (Optional)
NOTE: Liquid receivers MUST NOT be field installed unless the air-cooled condenser has been
specifically designed for use with a receiver.
If receivers are required the condenser coil must be ordered with a “receiver ready”
condenser coil (optional) or a factory installed receiver (optional).
Receivers are designed to hold excess refrigerant on systems that have variable refrigerant charges.
Typical applications are:
1.
Systems with reheat coils.
2. Low ambient systems.
3. Systems with long piping runs where the pump down charge will not fit into the condenser.
The refrigerant entering a receiver must be saturated. If subcooled liquid is introduced into a receiver, the
system will experience pressure fluctuations, and will generally operate poorly.
The refrigerant leaving a receiver is saturated; however, subcooling is required to prevent flashing in the
liquid line due to pressure drop or static losses in liquid risers. All required subcooling must be added
after
the receiver. Custom condenser coils must be ordered with separate subcooling circuits to allow
subcooling after the receiver.
Hot Gas Bypass (Optional)
NOTE:
Hot gas valves and hot gas solenoid valves must be installed close to the discharge line at the
condensing unit. Valves installed in the wrong location will cause compressor failure and void
warranty.
Hot gas bypass is a method of preventing evaporator frosting under low load conditions. The hot gas
bypass valve allows discharge gas into the low side of the system during low load conditions.
Correctly applied, a hot gas bypass system can reduce compressor cycling and prevent coil frosting during
low load conditions.
Caution:
Hot Gas bypass will cause system problems if it is not designed and piped correctly. If hot
gas bypass piping is oversized, or incorrectly installed, it can trap oil causing compressor
failures.
If the hot gas bypass valves are installed in the wrong location, the hot gas line can fill with
liquid refrigerant. Hot gas bypass piping should be insulated to reduce heat loss.
Two piping methods are acceptable.
1.
For systems with short piping runs and operation above 50°F (10°C) ambient. Hot gas is
piped to the suction header at the evaporator coil. The hot gas bypass valve (located at
the condensing unit) can be sized for up to 80% of the unloaded circuit capacity.
2.
For low ambient systems, less than 50°F (10°C), or systems with long piping runs, the hot