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Odyssey Refrigeration Miscellaneous Info.
Microchannel Heat Exchanger Condensers (MCHE)
This design improves heat transfer and the refrigerant that enters the coil quickly turns to liquid.
The MCHE tube volume holds very little refrigerant, so the refrigerant charge of the system is reduced.
However, the tube volume is so small that if the flow of refrigerant out of the MCHE condenser is
slowed much more than the flow of refrigerant into the MCHE condenser, the condenser may quickly fill
with liquid and cause a high-pressure control trip. To avoid this condition, the designer or servicer
should not include the following:
• Pump-down: The storage capacity of the MCHE won’t support pump-down.
• Trim solenoid: The storage capacity of the MCHE won’t support partial shut-off of the evaporator coil.
Solenoid Valves
In TTA split systems, solenoid valves may be used to isolate the refrigerant from the evaporator during
the off cycles. This is only done when the indoor unit is well below the outdoor unit.
The solenoid valve on the TTA unit is a drop solenoid—open when the compressor is on, and off when
the compressor is off.
If used, the solenoid requires code compliant wiring to the TTA condensing unit. (just a suggestion…you
could wire a 24 VAC solenoid in parallel with the compressor contactor)
Notes:
• Solenoids should not be used in the TWA heat pumps due to the reverse flow of the liquid.
Moisture-Indicating Sight glass
Be sure to install one moisture-indicating sight glass in the main liquid line.
Note: The sole value of the glass is its moisture indicating ability.
Use the Charging Charts—not the sight glass—to determine proper charge levels.
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