Heat is the first thing to design for
A screw compressor converts most of its electrical input into heat, and that heat has to leave the room. If it does not, the room warms up until the machine is running in air hotter than its rating, and every component downstream - motor, oil, dryer, filters - starts working outside its design point.
What the rating actually means
An ambient limit of about 45 C is a rating, not a target. Running at the limit leaves no margin for a hot afternoon, a blocked louvre or a second machine switched on for a busy week. Capacity tables are quoted at a reference ambient, and available flow falls as inlet temperature rises, so a machine that looks oversized on paper can be marginal in a badly ventilated room.
Three layouts that cause the problem
- A room with intake louvres but no clear outlet, so hot air recirculates.
- Machines pushed against a wall, with the discharge duct blowing into a corner.
- Ducting that runs long and undersized, adding static pressure until the fan delivers far less than its free-air figure.
What good ventilation looks like
Cold air enters low, hot air leaves high, and the path crosses the machines rather than short-circuiting past them. Ducted discharge is taken outside the room, not into the next bay. Where the building cannot be modified, a ducted exhaust with a correctly sized fan usually costs less than the capacity lost to a hot room.
Symptoms worth checking
Rising discharge temperature through the day, dryers cycling harder in summer, frequent high-temperature trips that clear overnight, and oil life shorter than the service interval suggests. All of them point at the room before they point at the machine.
Send us your working pressure, required flow and site conditions and we will propose a configuration. Contact OPPAIR.