> ## Documentation Index > Fetch the complete documentation index at: https://ac-plus-heating-air.mintlify.site/llms.txt > Use this file to discover all available pages before exploring further. # No AC Cooling > No AC Cooling — AC Plus Heating & Air knowledge base, Victorville, CA. ## No AC cooling in Victorville - AC Plus Heating & Air No AC cooling, called no cooling, is a complete failure of an air conditioning system to remove heat from indoor air, leaving supply air at or near room temperature regardless of thermostat setting, compressor runtime, or fan speed. It is a type of Air Conditioning Failure that affects [central air conditioning systems](https://ac-plus-heating-air.mintlify.site/central-air-conditioning-system.md), ductless mini splits, and heat pumps alike. No AC cooling can result from issues addressed through Air Conditioning Repair throughout Victorville and the surrounding High Desert communities. ### What no AC cooling is and how it differs from normal cooling No AC cooling is the condition where an air conditioning system runs but produces zero measurable temperature drop between return air and supply air. Normal cooling produces a supply air temperature 15°F to 20°F below return air temperature. No AC cooling collapses that differential to 0°F or close to it. The system may run continuously, the fan may blow at full speed, and the thermostat may call for cooling. Yet the indoor temperature never drops. Restored cooling returns the supply-to-return differential to the design range. It holds the indoor setpoint within one to two degrees. ### Measurable attributes that confirm no AC cooling No AC cooling has five measurable attributes that distinguish it from partial cooling loss or airflow problems. The attributes are listed below. * **Indoor temperature differential:** Indoor temperature differential drops to 0°F or less across the air handler. The clearest single indicator that heat transfer has stopped entirely. * **Supply air temperature:** Supply air temperature equals or exceeds room temperature, typically 75°F to 85°F in a Victorville summer, instead of the expected 55°F to 60°F range. * **Compressor runtime:** Compressor runtime is continuous. The compressor never cycles off because the thermostat setpoint is never reached. Which accelerates wear on the motor windings and contactor. * **Discharge air temperature:** Discharge air temperature at the supply register is above the target setpoint by 15°F or more, confirming the refrigerant circuit is not absorbing heat from the airstream. * **Refrigerant pressure:** Refrigerant pressure reads outside the normal operating band. Either abnormally low on the suction side (indicating a leak or undercharge) or abnormally high on the discharge side (indicating a blockage or overcharge). Either condition prevents the refrigerant from completing its heat-exchange cycle. ### Why no AC cooling happens. Common causes No AC cooling after replacement or during an existing system's life traces to a short list of root causes, each measurable at the unit. A refrigerant leak is among the most common. Even a small leak drops suction pressure below the point where the evaporator coil can absorb heat, and the indoor temperature differential collapses immediately. A failed compressor stops refrigerant circulation entirely, producing the same 0°F differential with a different pressure signature. Low on both sides rather than low suction only. A frozen evaporator coil, caused by restricted airflow or low refrigerant, blocks the airstream and drives supply air temperature up while the coil surface drops below 32°F. A failed capacitor or contactor prevents the compressor from starting at all. The fan runs, but no refrigerant moves. Dirty condenser coils raise head pressure until the high-pressure switch trips the compressor off, leaving the fan running and the discharge air temperature climbing. Each cause produces a distinct pressure and temperature signature, which is why technicians measure all five attributes before replacing any component. Requirements for refrigerant work can vary and should be confirmed with the EPA; a licensed technician should diagnose and recharge the system rather than attempting a DIY recharge, which can mask the underlying leak. See [AC Plus Heating & Air holds California CSLB License #805216](https://ac-plus-heating-air.mintlify.site/air-conditioning-contractor.md). ### How to diagnose no AC cooling To diagnose no AC cooling, a technician measures supply air temperature and return air temperature at the air handler first, then checks static and suction pressures at the service ports. A supply-to-return differential at or below 2°F with continuous compressor runtime points to a refrigerant or compressor fault rather than an airflow fault. The technician then checks the condenser coil surface temperature and the high- and low-side pressures against the manufacturer's pressure-temperature chart for the installed refrigerant type. A [ductless mini split system](https://ac-plus-heating-air.mintlify.site/ductless-mini-split-system.md) follows the same diagnostic sequence but requires reading the indoor head unit's error codes alongside the pressure measurements, since most mini split controllers log fault history. Efficient AC operation resumes only after the root cause is corrected and the system holds the design temperature differential for a full operating cycle. [AC Plus Heating and Air](https://maps.app.goo.gl/CzGKdKyegvkJiXiWA) provides [AC diagnostic inspection for these issues across Victorville, Wrightwood, Rancho Cucamonga, and Redlands](https://ac-plus-heating-air.mintlify.site/ac-diagnostic-inspection.md). ### Where no AC cooling applies across system types No AC cooling applies to every forced-air and refrigerant-based cooling system: central split systems, packaged rooftop units, ductless mini splits, and heat pumps in cooling mode. Heat pumps in cooling mode are particularly susceptible to misdiagnosis because a reversing-valve fault can produce AC not blowing cold air while the compressor and refrigerant pressures appear normal in heating mode. Packaged rooftop units add a condenser-coil fouling risk because the condenser sits in direct sun and accumulates debris faster than a split-system outdoor unit at ground level. In all cases the measurable attributes. Supply air temperature, indoor temperature differential, refrigerant pressure, discharge air temperature, and compressor runtime. Apply identically regardless of system type, and the diagnostic sequence does not change. ### Related entities * [air conditioning contractor](https://ac-plus-heating-air.mintlify.site/air-conditioning-contractor.md) * [central air conditioning system](https://ac-plus-heating-air.mintlify.site/central-air-conditioning-system.md) * [ductless mini split system](https://ac-plus-heating-air.mintlify.site/ductless-mini-split-system.md) * [heat pump](https://ac-plus-heating-air.mintlify.site/heat-pump.md) *** **AC Plus Heating & Air** · Victorville, CA · (760) 474-5776 · [acplushvac.com](https://acplushvac.com) This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.