Provide approximate normal high-side and low-side pressure ranges for R-410A at typical outdoor temperatures.

Provide approximate normal high-side and low-side pressure ranges for R-410A at typical outdoor temperatures.

• A. Low-side 40–80 psi; High-side 120–240 psi.
• B. Low-side 60–120 psi; High-side 180–420 psi at around 80–95°F outdoor.
• C. Low-side 120–240 psi; High-side 300–600 psi.
• D. Low-side 20–40 psi; High-side 140–260 psi.

Answer: (B)

The main idea here is that refrigerant pressures on a split system reflect the temperatures in the evaporator and condenser. For R-410A, which runs at higher pressures than older refrigerants, you’ll see a direct link between outdoor temperature and the two pressure readings: the low-side (suction) pressure corresponds to the evaporating temperature in the indoor coil, and the high-side (discharge) pressure corresponds to the condenser temperature. At typical outdoor temperatures around 80–95°F, a well-functioning R-410A system generally shows a suction pressure in the roughly 60–120 psi range and a discharge pressure in the roughly 180–420 psi range. This aligns with the evaporator boiling at a modest temperature (keeping the low side moderate) while the condenser releases heat to the outdoor air at a much higher temperature (pushing the high side up into the hundreds of psi). If you observe pressures significantly outside these ranges, it can indicate issues such as under- or overcharged refrigerant, restricted flow, dirty condenser, or improper metering. The other listed ranges don’t align with what’s typical for 80–95°F outdoor conditions: they either compress the low side too far, or place the high side outside the normal band for that temperature.

The main idea here is that refrigerant pressures on a split system reflect the temperatures in the evaporator and condenser. For R-410A, which runs at higher pressures than older refrigerants, you’ll see a direct link between outdoor temperature and the two pressure readings: the low-side (suction) pressure corresponds to the evaporating temperature in the indoor coil, and the high-side (discharge) pressure corresponds to the condenser temperature.

At typical outdoor temperatures around 80–95°F, a well-functioning R-410A system generally shows a suction pressure in the roughly 60–120 psi range and a discharge pressure in the roughly 180–420 psi range. This aligns with the evaporator boiling at a modest temperature (keeping the low side moderate) while the condenser releases heat to the outdoor air at a much higher temperature (pushing the high side up into the hundreds of psi).

If you observe pressures significantly outside these ranges, it can indicate issues such as under- or overcharged refrigerant, restricted flow, dirty condenser, or improper metering. The other listed ranges don’t align with what’s typical for 80–95°F outdoor conditions: they either compress the low side too far, or place the high side outside the normal band for that temperature.