Air and dirt separator annual maintenance checklist

As-found readings taken with the loop still running

Loop pressure at the nearest gauge, plus any pressure drop across the separator, read and photographed before isolation so post-service readings have a baseline.

Owner told the loop loses flow while the separator is out

Owner and building operator told when the loop goes down or onto bypass, with pumps and the heating or cooling plant held off by their own procedures while the separator is open.

Isolation valves closed and tagged and the body relieved

Inlet and outlet valves closed and tagged under the site's procedure, the body drained through the blowdown until flow stops and let cool before any head bolt is loosened.

Coalescing element cleaned or replaced

Separator isolated and drained, the internal coalescing medium pulled and cleaned or replaced per the instructions, magnetite and sludge flushed from the body before it closes back up.

Magnetic insert cleaned and its sleeve checked where fitted

Magnet withdrawn and captured magnetite wiped into a bag, the sleeve checked for cracks that would let loop water reach the magnet, then reseated, a step past the quarterly pull.

Shell interior inspected where the model has a removable head

Where the model has a removable head, inside of the shell, the inlet and outlet nozzles and the dirt leg checked for erosion, scale and pitting, findings shared with the treatment contractor.

Dirt leg flushed clear and blowdown valve serviced

Dirt leg flushed with clean water until it runs clear, blowdown valve stroked fully and repacked or replaced if it weeps, so next quarter's blowdown isn't blocked.

Air vent serviced and connections resealed

Automatic air vent cleaned or rebuilt, float and seat seen releasing air and reseating dry, flange gaskets and threaded connections resealed with no weeping on refill.

Head bolts torqued where the model has a removable head

Where the model has a removable head, its bolts or clamp tightened in a cross pattern to the manufacturer's value with a torque wrench, so the gasket seals evenly without crushing.

System refilled, vented and pressure confirmed

Loop refilled and vented at the high points, isolation valves returned fully open, system pressure back at its fill value with the make-up not running on.

Pressure drop compared with the as-found after cleaning

Where gauged, pressure drop across the separator read at normal flow and set against the as-found and commissioning values, a drop still high after cleaning reported.

Glycol mix restored and checked after the drain

On a glycol loop, drained volume replaced with the specified mix and concentration read on a refractometer, drained glycol disposed of per site rules.

Insulation refitted over the head and dirt leg

Insulation removed for the service refitted and sealed, going further than the quarterly look, with the vapor barrier closed on a chilled loop so the body won't sweat.

Tags cleared and annual separator findings filed

Isolation tags removed by whoever hung them, owner told flow is restored, and element, magnetite and pressure findings filed and sent to the treatment contractor.