REPLACING THE INDOOR COIL THERMISTOR

WARNING

ELECTRIC SHOCK HAZARD

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

Remove the decorative front cover (see page 30). Remove all indicated screws below (8 total, see figure below). Remove the Discharge Sensor and the User Interface plugs from the control board.

Remove the screws indicated at the side and back plate (6 total, see figure below). Partially lift the top cover and at the same time carefully swing out from the top, the back and side plate.

Up

Swing

Out

Replace the indoor coil sensor. Ensure to properly clip and insulate it at the same location (see figure below).

REPLACING THE CONTROL BOARD

WARNING

ELECTRIC SHOCK HAZARD

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

Remove the decorative front cover (see page 30). Disconnect discharge sensor plug (red) Disconnect the User Interface plug (white) Remove the 3 screws indicated below.

Pull control board and mount plate out and disconnect the following connectors from it:

Power, capacitor, thermistors, fan, reversing valve and heater.

Remove the hex screw holding the control board to its mount plate. Pull out the control board (see figure below).

31

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Friedrich R-410A service manual Replacing the Indoor Coil Thermistor, Swing Out
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R-410A specifications

Friedrich R-410A is an advanced refrigerant widely used in HVAC (Heating, Ventilation, and Air Conditioning) systems, known for its high efficiency and environmental friendliness. As a hydrofluorocarbon (HFC) blend, R-410A has become the preferred alternative to R-22, which is being phased out due to its ozone-depleting potential. One of the main features of R-410A is its high latent heat of vaporization, which allows for efficient heat transfer and improved cooling performance in air conditioning units.

Technologically, R-410A operates at higher pressures than older refrigerants, meaning systems designed for R-410A need to be built with more robust components to safely handle these pressures. This results in a more compact system design that offers enhanced performance and reliability. The dual-component nature of R-410A—composed of difluoromethane (R-32) and pentafluoroethane (R-125)—provides an optimal balance of thermodynamic properties, leading to superior energy efficiency, especially in variable speed applications.

In terms of characteristics, R-410A has a higher cooling capacity, which enables HVAC systems to effectively cool larger spaces or run more efficiently when cooling smaller areas. The refrigerant is non-toxic and non-flammable, which enhances safety during its use. In addition, R-410A has a lower global warming potential relative to other refrigerants, making it a more environmentally responsible choice for modern cooling systems.

Moreover, R-410A systems typically require less refrigerant charge due to their efficiency, contributing to reduced greenhouse gas emissions. The adoption of R-410A aligns with regulatory trends aimed at minimizing the environmental impact of refrigerants in cooling applications.

Overall, the Friedrich R-410A refrigerant embodies a combination of technology and environmental stewardship, making it a cornerstone of contemporary HVAC design. Its ability to provide effective and energy-efficient cooling solutions while being compliant with modern environmental regulations positions R-410A as the refrigerant of choice for engineers and installers focused on sustainability and performance in air conditioning systems.
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