What is a hot gas bypass line?
The hot gas bypass is a valve that automatically regulates the cooling temperature in the dryer exchanger based on the refrigerant pressure. The pressure measured after the heat exchanger directly correlates to the temperature in the system. A low pressure means there will be a low temperature.
How is the hot gas bypass line installed in an evaporator feed capacity control system?
STANDARD (EXTERNAL) HOT GAS BYPASS A check valve is installed in the evaporator section in the hot gas line before it enters the suction side. This is to prevent the liquid in the bypass “off cycle” from filling the line and slugging the refrigerant lines on bypass/compressor start cycle.
Is hot gas bypass the same as hot gas reheat?
HOT GAS REHEAT uses the high pressure, high temperature, compressor discharge gas to reheat the air leaving the evaporator coil. HOT GAS BYPASS provides an artificial load on the evaporator by introducing a portion of high pressure, high temperature gas to the evaporator/suction side of the system.
What does a discharge bypass valve do?
On refrigeration systems, discharge bypass valves are used to prevent the suction pressure from going below the minimum value recommended by the compressor manufacturer.
How does the hot gas bypass work?
Hot gas bypass can stabilize the system balance point by diverting hot, high-pressure refrigerant vapor from the discharge line directly to the low- pressure side of the system. This tactic reliable operation by introducing problems stemming from insufficient oil return and refrigerant logging in the HGBP line.
Does hot gas bypass dehumidify?
With this system, you have two coils in the air handling unit. The air first travels across a cooling coil which de- humidifies, then it crosses the hot gas coil that raises the air temp back up 15-20 degrees to further dehumidify and render the air neutral, eliminating over-cooling.
What is a Humidimizer?
“The Humidi-MiZer adaptive dehumidification system is no exception. Using a simple space thermostat and humidistat input, the Humidi-MiZer system changes the refrigerant flow by adjusting the position of the refrigerant solenoid valves. There are three modes of operation: normal, sub-cooling and hot gas reheat.
Why do you need hot gas bypass?
What is a headmaster valve?
The headmaster controls the head pressure of a refrigeration system during low ambient conditions. Under normal conditions, the pressure from the receiver pushes against the valve dome pressure and keeps the seat closed between the discharge line and receiver.
What is a Humidi MiZer?
How does the hot gas bypass system work?
The hot gas bypass valve monitors the outlet pressure of the evaporator and will begin to modulate open as the load on the unit decreases to the point where the evaporator temperature is at the setpoint of the bypass valve. The bypass valves are factory adjusted to a setting of 61 psig (35°F evaporator temperature).
How to determine line size for hot gas bypass?
Line sizing should be calculated to not exceed a 6 to 12 psi pressure drop. To select the correct refrigerant pipe size for the External Hot Gas Bypass reference Table 1 for units of 50 feet of run or less. Refer to Table 2 for piping runs between 50 and up to 100 feet.
What happens when hot gas is injected into the suction line?
If the hot gas injected into the suction line is before the sensing bulb, the expansion valve will try to compensate by adding liquid to the evaporator to lower the superheat which will lead to a roller coaster ride between the expansion valve and the hot gas regulator.
What are the first steps in refrigerant piping design?
The first step in refrigerant piping design is to gather product and jobsite information. A checklist for each is provided below. How this information is used will be explained throughout the rest of this guide. Product Information • Model number of unit components (condensing section,