Lone Star Cooling and Heating
Get help with Rooftop Unit Service
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Call (325) 219-0005Rooftop heating and cooling units repaired where they sit, from belts, motors and controls to economizers and compressors, and replaced by crane when a unit has reached the end of its useful life.
01Rooftop units
Most rooftop unit problems show up in the space below before anyone looks at the roof.
A failed compressor or condenser fan, a condenser coil clogged with dirt, a low refrigerant charge or an economizer stuck open on a hot day can all leave a rooftop unit moving air without cooling it. Each is checked at the unit before parts are ordered.
Many rooftop units drive their supply fan with a belt. A belt that has stretched, slipped or snapped, along with clogged filters or a blocked indoor coil, cuts the air reaching the space even while the rest of the unit runs.
A blocked condensate drain, a cracked drain pan or a failed seal between the unit and its roof curb can send water into the building. Where the water enters decides whether the fix is at the unit or at the roof around it.
A high squeal when the unit starts is often a worn or loose belt slipping on its pulley. Replacing and adjusting the belt is routine, and left alone it tends to fail completely and stop the airflow.
The outdoor air dampers on a rooftop unit decide how much fresh air comes in. Stuck shut, they leave the air stale. Stuck open, they pull in hot, humid or cold air that the unit then struggles against.
02Roof or crane
Almost anything inside a rooftop unit can be changed where it sits. Replacing the unit itself is a different kind of job.
Belts, fan motors, capacitors, contactors, control boards, economizer parts and even compressors can usually be changed at the unit. The work needs safe roof access and a way to raise parts, but the unit stays on its curb and connected to the building.
The old unit comes down and the new one goes up in a planned lift. The new unit has to sit on the existing curb or on an adapter made to match it, and its gas, power, duct and drain connections are all remade before it starts.
Rooftop Unit Service
Serving Abilene, TX.
03The economizer
Many rooftop units carry an economizer, and when it fails, the symptoms rarely point at it.
An economizer is a set of dampers, a motor to move them and sensors that judge the outdoor air. When the air outside is cool and dry enough, it opens to let that air do the cooling and gives the compressor a rest. At other times it holds the dampers at the minimum needed to supply fresh air to the people inside.
A failed economizer seldom stops the unit, so it can go unnoticed for years. Dampers stuck shut leave the air stale and give up free cooling. Dampers stuck open drag in hot, humid summer air or cold winter air, so the unit runs harder and the space never quite feels right. A sensor, actuator or linkage is usually at fault, and a rooftop service visit that skips the economizer misses a common problem.
04What changes the job
Where the unit sits shapes the job as much as what failed inside it.
A fixed ladder, a roof hatch or an outside lift decides how technicians and parts reach the unit, and a roof with no safe way up adds a step before any repair begins.
Foot traffic, dropped panels and loose screws can puncture a roof membrane. Walkway pads, care around the curb and a clean roof afterwards keep a repair on the unit from turning into a roof leak.
A replacement lift needs a place for the crane to stand, a clear path over the building, and sometimes a lane or parking area closed for the morning. Tight streets and tall buildings make the lift a larger job.
Rooftop units from different makers and eras sit on curbs of different sizes. A new unit that matches the old curb goes straight on, while a different size needs an adapter curb fitted and sealed first.
05Questions
The usual causes are a blocked condensate drain, a cracked drain pan inside the unit, or a gap in the seal where the unit meets its curb. A technician checks the drain and pan first, and a leak at the curb or roof flashing may also need a roofer.
A set of dampers and controls that brings in outdoor air when it is cool and dry enough to cool the space without running the compressor. It also supplies fresh air for the people inside. When it sticks or its sensor fails, it can waste energy or leave the air stale.
In most cases, because a complete unit is far too heavy to carry up a ladder or through a roof hatch. The lift is planned for a time when the street, the weather and the business all allow it, and the old unit comes down on the same lift.
What the system is doing, when it started, what the thermostat is set to and what it reads, and whether the outdoor unit is running. The age of the equipment and a photo of its label help a technician arrive prepared.
Lone Star Cooling and Heating
Call Lone Star Cooling and Heating, have us call you, or describe the issue.
Prefer to talk?
Call (325) 219-0005