--- title: "Cellar Cooling Unit Exhaust Overheating: Causes and Fixes" description: "A cellar cooling unit exhaust overheating makes the room on the other side of the wall uncomfortably warm, blows hot air hard enough to feel from across the…" url: "https://winecellarrepair.center/problems/cellar-unit-exhaust-overheating/" --- # Cellar Cooling Unit Exhaust Overheating A cellar cooling unit exhaust overheating makes the room on the other side of the wall uncomfortably warm, blows hot air hard enough to feel from across the room, and often makes the unit stop and restart in the afternoon. ## What it usually means. Every bit of heat the unit takes out of the cellar, plus the heat of its own motor, leaves by the exhaust side. A through-the-wall unit blows it into the next room, a ducted unit sends it down a duct, and a split system dumps it at an outdoor condenser. Makers set limits for that space: it should be at least as large as the cellar, open or well ventilated, and not much hotter than the high 80s. When the exhaust goes into a closet, a small mechanical room or a garage that bakes in summer, the unit breathes its own hot air back in, pressures climb, and it cools less while working harder. A dirty condenser coil or a slow hot-side fan causes the same heat at the source. Overheating is where many compressor failures begin, so it is worth fixing before it turns into a warm cellar. The 5 causes, cheapest first Answer these first 01 What is in the room or space the exhaust blows into, and how big is it? 02 Is that space closed off, with a door that stays shut? 03 How warm does it get there on a summer afternoon? 04 Is the hot-side coil visibly dusty, and does the hot-side fan turn? 05 Does the unit stop and restart on its own during hot hours? ## Check these before you book. Cellar cooling unit exhaust overheating: 5 checks, and none of them costs anything. 01 Open the door of the exhaust space, or prop it, and see whether the unit settles. 02 Clear boxes, coats or furniture away from the hot-side grille. 03 Check whether the hot-side fan turns while the unit runs. ### Also worth checking - On a split system, clear plants and debris from around the outdoor condenser. - Tell us the make, the model number and what the exhaust space is. ### How soon does it need a visit? Not urgent while the cellar holds its temperature, but a unit overheating every afternoon is shortening its compressor's life. Book within a week or two. ## The causes, cheapest first. 5 things cellar cooling unit exhaust overheating turns out to be, from hot-side coil clogged to exhaust into a closed or small space. [The cost guide](https://winecellarrepair.center/cost/) 1. 01 low ### Hot-side coil clogged Dust and pet hair on the condenser coil trap heat inside the unit. Cleaning it is routine maintenance and often lowers the exhaust temperature noticeably. [Fixed by cellar evaporator and condenser fan repair](https://winecellarrepair.center/services/cellar-evaporator-and-condenser-fan-repair/) 2. 02 low to moderate ### Hot-side fan slow or stopped Without its fan the condenser cannot shed heat, and the unit trips on overload. [Fixed by cellar evaporator and condenser fan repair](https://winecellarrepair.center/services/cellar-evaporator-and-condenser-fan-repair/) [See cellar cooling unit fan not running](https://winecellarrepair.center/problems/cellar-unit-fan-not-running/) 3. 03 low to moderate ### Exhaust duct crushed or too long On a ducted unit, a flexible duct that is kinked, crushed or longer than the maker allows restricts the hot air and backs heat into the unit. [Fixed by cellar cooling load and room check](https://winecellarrepair.center/services/cellar-cooling-load-and-room-check/) [On a ducted cellar cooling unit](https://winecellarrepair.center/types/ducted-cellar-cooling-unit-repair/) 4. 04 low ### Outdoor condenser in sun or blocked On a split system, a condenser crowded by plants, fences or debris, or sitting in full afternoon sun, runs hot and loses capacity. [Fixed by cellar evaporator and condenser fan repair](https://winecellarrepair.center/services/cellar-evaporator-and-condenser-fan-repair/) [On a split-system cellar cooling](https://winecellarrepair.center/types/split-system-cellar-cooling-repair/) 5. 05 varies ### Exhaust into a closed or small space A closet or small room fills with the unit's heat in an hour. The answer can be a louvered door, a vent, a duct to a larger space or relocating the exhaust, which a room check will lay out. [Fixed by cellar cooling load and room check](https://winecellarrepair.center/services/cellar-cooling-load-and-room-check/) 6. What it costs ### Every repair on the site's cost scale, side by side Open the cost guide ## What else it could be. Most often confused with wine cellar too warm, then cellar cooling unit running constantly. [All problems](https://winecellarrepair.center/problems/) Codes that come with it - [`E1` Breezaire · Temperature and alarms](https://winecellarrepair.center/error-codes/breezaire-e1/) - [`OH` Breezaire · Temperature and alarms](https://winecellarrepair.center/error-codes/breezaire-oh/) - [`AH1` CellarCool · Temperature and alarms](https://winecellarrepair.center/error-codes/cellarcool-ah1/) - [`P3` CellarPro · Sensors and probes](https://winecellarrepair.center/error-codes/cellarpro-p3/) - [`HA2` CellarPro · Fans and airflow](https://winecellarrepair.center/error-codes/cellarpro-ha2/) - [`AL` KoolR · Temperature and alarms](https://winecellarrepair.center/error-codes/koolr-al/) [4 more codes, by make](https://winecellarrepair.center/error-codes/) Also related - [**Cellar Cooling Unit Fan Not Running** 4 causes](https://winecellarrepair.center/problems/cellar-unit-fan-not-running/) The collection is exposed ### Wine Cellar Too Warm 6 causes ### Cellar Cooling Unit Running Constantly 5 causes ### Cellar Cooling Unit Short Cycling 5 causes ## The makes it happens on. 7 makes on this site; cellar cooling unit exhaust overheating can show up on any of them. Each mark opens that make's own page. [All 7 brands](https://winecellarrepair.center/brands/) ## Cellar Cooling Unit Exhaust Overheating, where we come out. 9 metros, each with its own page. 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Only if the closet is large, ventilated and stays cool; most makers call for a space at least as large as the cellar with good air. A closed closet overheats quickly and the unit loses much of its cooling. ### How hot can the exhaust side get before it matters? Makers typically give an upper limit somewhere in the high 80s to low 90s for the air entering the hot side. Your model's manual has the figure; above it, cooling falls off fast. ### Is it normal for the room next to the cellar to be warm? Slightly warmer, yes, since the heat has to go somewhere. Uncomfortably hot means the space is too small, too closed or the unit is working too hard. ### Could we duct the exhaust somewhere else? Often, with a ducted unit or an exhaust kit your model supports. It depends on the unit and the distance; a room check shows what is possible. --- **[Read on the site: Cellar Cooling Unit Exhaust Overheating: Causes and Fixes](https://winecellarrepair.center/problems/cellar-unit-exhaust-overheating/)** **[Book a visit with WineCellarRepair.center](https://winecellarrepair.center/schedule/)**