Water-source heat pump quarterly maintenance checklist

Zone occupants told and the floor under the access panel covered

Occupants of the zone told the unit will be off for a short spell, desks and flooring under the ceiling access or closet door covered before the filter comes out.

Lock and tag on every circuit feeding the unit

Unit and any separate heat or control feed locked out, zero voltage proven. Running checks: panels on, people clear, locks off by whoever hung them, re-locked before hands go back in.

Filter replaced and coil face inspected

Filter changed and correctly sized, no bypass around the rack, coil face clean behind it with no matting or bent fins visible.

Condensate pan clear and float switch proven

Pan draining fully with no standing water or growth, trap primed, float switch lifted to confirm it interrupts the unit or alarms, secondary pan dry over occupied space.

Blower running clean and quiet

Wheel free of build-up, set screw tight, motor mounts sound, no rattle or bearing noise at each speed tap.

Return air path open at the closet louver or ceiling grille

Return grille, closet door louver or plenum opening to the unit free of stored boxes, blocked louvers or displaced ceiling tile, so the unit is not starved of return air.

Hose kit, isolation valves and connections dry

Supply and return hose kits, isolation ball valves and unions free of weeping or drips, no rust trail or wet insulation at the coax connections.

Water connections free of strain, kinks and chafe

Hoses or hard piping to the unit supported, not kinked, twisted or rubbing on the grid or cabinet edge, and not carrying the weight of the valves.

Loop flow and pressure drop reasonable across the unit

Supply and return pressures or the pressure drop across the coax read against the balanced value, no sign of a fouling strainer or a throttled autoflow starving the exchanger.

Unit heats and cools on a call

Heat and cool each commanded from the thermostat, reversing valve shifting so discharge air changes over, entering and leaving water temperatures moving as expected, no fault on the board.

Lockout history read at the board light or building controls

Board light read through the cabinet sight hole, or the fault read at the thermostat or building controls, panels left on; any pressure or freeze lockout noted with its cause.

Panels and tile back, locks removed and unit left running

Access panels and ceiling tile refitted, locks removed by whoever hung them, thermostat back on its normal schedule and the unit running on a call with no fault showing.

Water readings and lockouts logged by unit tag and zone

Water temperature split set against the unit schedule and last quarter, plus pressure drop, filter condition and any lockout, entered by unit tag and zone.