Readiness check

Is your RTU install and startup actually ready?

A packaged RTU will hum and blow air on day one even when the curb is crooked, the drain has no trap, and the compressor runs backward. It fails slowly, and the callback lands on whoever signed the startup sheet. This check walks the readiness items the guide treats as the difference between a unit that was commissioned and one that was just turned on.

1. Before the unit was set, did you confirm the curb is dead level on both axes and sealed watertight with a continuous gasket?Checked level across both axes, shimmed true, flashing and a continuous gasket with no corner gaps confirmed, unit set onceEyeballed roughly level or set the unit more than once onto the gasketSet the unit to match the roof slope, or did not check the gasket or flashing

2. Is the condensate drain trapped deep enough to beat the worst-case negative static, primed, sloped away, and given an overflow path?Trap sized to the loaded-filter worst case per the unit's rated static, primed before startup, sloped, with a primary and overflow, and water poured in the pan drained throughTrapped and sloped but sized off the clean day-one reading, or not primed, or no overflow pathNo trap on a draw-through unit, or never verified water leaves the pan

3. Were the shipping bolts and blocks pulled and service and condenser clearances set before you energized?Located every hold-down the manufacturer marks, removed what the instructions say, and confirmed condenser and service clearances meet the minimumsPulled the obvious compressor bolts but did not check the blower blocks or clearancesRan the unit with shipping hold-downs still tight or against a parapet

4. On a three-phase unit, did you verify rotation by the pressure split at the first start?Watched gauges and listened at start, confirmed suction drops and head rises, checked supply and condenser fans turn right, corrected by swapping two legs with power verified dead if neededListened but did not watch both pressures, or checked the compressor only and not the fansNever checked rotation, or kept cycling a reversed compressor to re-listen

5. Did you set and verify airflow by ESP against the blower table before touching the charge?Measured supply and return ESP at the test points, matched design CFM on the blower table, and traced a high ESP to the duct or filter rather than overspeeding the blowerRead airflow but did not confirm it against the blower table, or accepted a high ESP without finding the restrictionJudged the charge with airflow never set, or overspun the blower to force air against a bad duct

6. Did you verify the refrigerant charge by the method the metering device picks, with the system stabilized and conditions noted?Subcooling on the TXV or superheat on the fixed orifice, to the manufacturer's target or chart for the measured indoor wet-bulb and outdoor dry-bulb, after the system stabilizedRead the right number but off a memorized target instead of the plate or chart, or before the system stabilizedUsed superheat on a TXV or subcooling on a fixed orifice, or chased pressures with airflow unset

7. On a gas unit, does the temperature rise land in the nameplate range with the manifold pressure set to the rating plate?Airflow set first, manifold pressure set with a manometer to the rating plate, measured rise falls inside the nameplate range, flue and combustion checked cleanRise is roughly in range but manifold pressure not verified with a manometer, or combustion not checkedRise out of range, or the unit only stays in range because the high limit keeps cutting the burners

8. Are every startup reading and its target recorded on the manufacturer's startup form with corrections and deficiencies noted?Manufacturer's form filled completely: charge with conditions, pressures, temp split, ESP and CFM, amps, rotation, manifold and rise, economizer, with passes, fails, and corrections notedSome readings captured on a generic sheet, but conditions or corrections missing so numbers cannot be reproducedUnit called done with no readings recorded, so there is no baseline and no warranty proof