REVERSING VALVE DESCRIPTION/OPERATION

WARNING

ELECTRIC SHOCK HAZARD

Disconnect power to the unit before servicing. Failure to follow this warning could result in serious injury or death.

The Reversing Valve controls the direction of refrigerant flow to the indoor and outdoor coils. It consists of a pressure- operated, main valve and a pilot valve actuated by a solenoid plunger. The solenoid is energized during the heating cycle only. The reversing valves used in the PTAC system is a 2-position, 4-way valve.

The single tube on one side of the main valve body is the high-pressure inlet to the valve from the compressor. The center tube on the opposite side is connected to the low pressure (suction) side of the system. The other two are connected to the indoor and outdoor coils. Small capillary tubes connect each end of the main valve cylinder to the “A” and “B” ports of the pilot valve. A third capillary is a common return line from these ports to the suction tube on the main valve body. Four-way reversing valves also have a capillary tube from the compressor discharge tube to the pilot valve.

The piston assembly in the main valve can only be shifted by the pressure differential between the high and low sides

of the system. The pilot section of the valve opens and closes ports for the small capillary tubes to the main valve to cause it to shift.

NOTE: System operating pressures must be near normal before valve can shift.

TESTING THE COIL

WARNING

ELECTRIC SHOCK HAZARD

Unplug and/or disconnect all electrical power to the unit before performing inspections, maintenances or service.

Failure to do so could result in electric shock, serious injury or death.

The solenoid coil is an electromagnetic type coil mounted on the reversing valve and is energized during the operation of the compressor in the heating cycle.

1.Turn off high voltage electrical power to unit.

2.Unplug line voltage lead from reversing valve coil.

3.Check for electrical continuity through the coil. If you do not have continuity replace the coil.

4.Check from each lead of coil to the copper liquid line as it leaves the unit or the ground lug. There should be no continuity between either of the coil leads and ground; if there is, coil is grounded and must be replaced.

5.If coil tests okay, reconnect the electrical leads.

6.Make sure coil has been assembled correctly.

NOTE: Do not start unit with solenoid coil removed from valve, or do not remove coil after unit is in operation. This will cause the coil to burn out.

CHECKING THE REVERSING VALVE

NOTE: You must have normal operating pressures before the reversing valve can shift.

WARNING

HIGH PRESSURE HAZARD

Sealed Refrigeration System contains refrigerant and oil under high pressure.

Proper safety procedures must be followed, and proper protective clothing must be worn when working with refrigerants.

Failure to follow these procedures could result in serious injury or death.

Check the operation of the valve by starting the system and switching the operation from “Cooling” to “Heating” and then back to “Cooling”. Do not hammer on valve.

Occasionally, the reversing valve may stick in the heating or cooling position or in the mid-position.

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Friedrich H)A18K25L, R410A, H)A12K25L Reversing Valve DESCRIPTION/OPERATION, Testing the Coil, Checking the Reversing Valve
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H)A09K25L, H)A12K50L, H)A09K50L, H)A24K10L, H)A24K25L specifications

Friedrich R410A is a refrigerant blend that has become a cornerstone in the HVAC industry, particularly for air conditioning systems. This hydrofluorocarbon (HFC) is known for its efficiency and environmentally friendly properties, making it a popular alternative to older refrigerants like R22.

One of the main features of R410A is its exceptional thermal efficiency. It has a higher cooling capacity compared to R22, which allows for smaller and more efficient equipment. This efficiency translates to reduced energy consumption and lower operating costs for users. Additionally, the higher pressure capability of R410A enables the design of more compact systems, which is particularly beneficial for residential and commercial applications where space is often limited.

R410A is characterized by its zero ozone depletion potential (ODP), which is a significant advantage over its predecessors. This makes it a more environmentally responsible choice, aligning with global initiatives to phase out substances that harm the ozone layer. However, it is essential to note that while R410A does not deplete the ozone, it does have a global warming potential (GWP) of approximately 2,088, making it less favorable in terms of climate impact compared to natural refrigerants.

In terms of technology, R410A is typically utilized in systems that are designed specifically for this refrigerant. Equipment compatible with R410A often features advanced components that can handle the higher pressures required. Many modern air conditioning systems equipped with R410A also incorporate variable-speed compressors and advanced electronic controls, enhancing overall performance and comfort.

Additionally, R410A systems often come equipped with variable refrigerant flow (VRF) technology, which allows for precise temperature control in multiple zones of a building. This versatility makes R410A an ideal choice for both residential and commercial installations, providing optimal comfort throughout various spaces.

In summary, Friedrich R410A stands out due to its high energy efficiency, zero ozone depletion potential, and suitability for modern HVAC technologies. As the industry moves towards more sustainable practices, R410A serves as a reliable refrigerant that balances performance with environmental responsibility. It’s a significant choice for anyone looking to invest in efficient and eco-friendly heating and cooling solutions.
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