Planned maintenance. A checklist for every visit.

Monobloc or split air-to-water heat pumps for heating and hot water.

Before you start

• Read the controller error and alarm history; record any faults (annually)
• Isolate the outdoor unit and controls; prove dead before opening covers (annually)
• Check the F-gas or refrigerant label is present; record whether leak checks apply (annually)

Outdoor unit

• Clear leaves and debris from the coil, fan outlet and base; check airflow clearances (every 6 months)
• Clean the evaporator coil gently; straighten damaged fins (annually)
• Check the defrost drain and condensate path are clear and will not freeze or flood paths (annually)
• Check the fan, guard, mounting feet, anti-vibration pads and base for security (annually)
• Check flexible hoses or pipe connections to the unit for leaks and perishing (annually)
• Inspect pipe insulation outside the building; replace damaged or missing sections (annually)

Hydraulics

• Check and record system pressure cold; top up and find the cause if it has dropped (annually)
• Check expansion vessel pre-charge with the system side depressurised (annually)
• Clean the strainer or magnetic filter; note how much debris was collected (annually)
• Test inhibitor concentration or antifreeze (glycol) strength and record the reading (annually)
• Check frost protection valves and anti-freeze devices where fitted (annually)
• Record flow and return temperatures and flow rate under load; compare with commissioning (annually)
• Bleed air from high points and check automatic air vents are not weeping (annually)

Hot water cylinder

• Manually operate the temperature and pressure relief valve and check the tundish and discharge (annually)
• Check the unvented cylinder expansion vessel or air gap to the manufacturer’s procedure (annually)
• Confirm the legionella (pasteurisation) cycle is set and has run, and the immersion heater works (annually)
• Check stored hot water temperature at the cylinder and the furthest outlet (annually)

Controls and electrical

• Check terminations, contactors and isolators for tightness and heat damage (annually)
• Check weather compensation curve, schedules and set points match the agreed settings (annually)
• Check the outdoor air sensor is shaded, secure and reading sensibly (annually)
• Update controller software if the manufacturer recommends it (annually)
• Run the system and confirm heating and hot water operate; explain any changes to the customer (annually)

Packaged or built-up AHUs with filters, coils, fans and optional heat recovery.

Before you start

• Agree shutdown with the site or BMS operator; isolate and lock off at the local isolator (monthly)
• Wait for fans to stop fully before opening access doors (monthly)

Filters

• Record filter differential pressure on each bank against the clean and final values (monthly)
• Replace filters at the final pressure drop or the scheduled interval, whichever is first (every 3 months)
• Check filter frames and seals for bypass gaps; bag the old filters before removal (every 3 months)
• Check pressure gauge or sensor tubing is connected and reading (every 6 months)

Fans and drives

• Check belt tension and alignment; replace worn or cracked belts as a set (every 3 months)
• Listen for bearing noise and check for vibration; record motor current (every 3 months)
• Lubricate bearings where not sealed for life, to the manufacturer’s schedule (every 6 months)
• Clean fan impellers and check balance weights and fixings (every 6 months)
• Check anti-vibration mounts and flexible connections for splits (annually)

Coils and drain trays

• Clean and check condensate drain trays slope to the outlet and do not hold water (every 3 months)
• Check traps on the condensate drain are primed and the correct depth for the fan pressure (every 3 months)
• Inspect heating and cooling coil faces; clean when fouled (every 6 months)
• Test frost protection (frost thermostat or sensor) trips heating to full and stops the fan as designed (every 6 months)
• Check coil valves and actuators stroke fully open and closed (annually)

Heat recovery and dampers

• Check thermal wheel drive, seals and purge sector; or plate heat exchanger for fouling (every 6 months)
• Check fresh air, exhaust and recirculation dampers move through full travel (every 6 months)
• Check damper linkages are tight and actuators match BMS position (annually)

Humidifier (if fitted)

• Inspect for scale, slime or standing water; clean and disinfect as the water risk assessment requires (monthly)
• Check steam cylinders or nozzles, drains and controls; replace consumables (every 6 months)

Casing, controls and performance

• Check access door seals and latches; no air leaks or water ingress (every 6 months)
• Check BMS sensors against a calibrated reference: temperature, humidity, pressure (annually)
• Measure and record airflow or fan speed against the design or commissioning figures (annually)
• Check electrical terminations, VSDs and panel cooling fans with power isolated where required (annually)
• Restore the unit, confirm normal running on the BMS and record the visit (monthly)

Plant room checks around gas-fired boilers, pumps and pressurisation. Combustion work needs Gas Safe registration for the appliance type.

Plant room

• Check the plant room is clear of stored materials and combustibles; access is unobstructed (monthly)
• Check permanent ventilation openings are open and not blocked (monthly)
• Check lighting and emergency lighting work (every 3 months)
• Check the schematic, emergency procedures and isolation points are displayed and current (annually)

Gas safety

• Check the gas detection system is in service and no alarms are active (every 3 months)
• Test the emergency gas shut-off valve or interlock operates (by a competent gas engineer) (annually)
• Arrange gas tightness test and appliance service by a Gas Safe registered engineer (annually)

Boilers

• Check each boiler for fault lockouts, leaks, and unusual noise or smell (monthly)
• Record combustion analysis readings from the service engineer’s report (annually)
• Inspect flue and chimney route, terminals and supports for damage and leaks (annually)
• Check condensate drains and neutraliser; replace neutraliser media as needed (every 6 months)

Pumps and pipework

• Check pumps for leaks, noise and overheating; confirm duty/standby changeover works (monthly)
• Check strainers and dirt separators; clean if the pressure drop has increased (every 3 months)
• Check insulation, labels and flow direction arrows on pipework (every 6 months)
• Exercise isolating valves through full travel (annually)

Pressurisation and water treatment

• Record system pressure; check the pressurisation unit is not short cycling (monthly)
• Check expansion vessel pre-charge (every 6 months)
• Take a system water sample or test inhibitor level; record the result (every 3 months)
• Manually check safety valves discharge freely and reseat (where safe to do so) (annually)

Records

• Record readings and defects in the plant room log book (monthly)
• Confirm gas safety and service records are on file (annually)

Walk-in chiller or freezer room with remote or packaged condensing unit.

Room and doors

• Check door seals for splits and gaps; check door closer and hinges (monthly)
• Test the person-trapped alarm and inside door release (monthly)
• Check door frame or perimeter heaters on freezer rooms (every 3 months)
• Check panels, joints and floor for damage, ice build-up or water (every 3 months)
• Check lighting and guards inside the room (every 3 months)

Evaporator

• Check the evaporator coil is clear of ice after defrost; clean if dirty (every 3 months)
• Watch a defrost cycle: heaters or hot gas work and terminate correctly (every 3 months)
• Check the drain tray and drain line are clear; drain line heater works on freezer rooms (every 3 months)
• Check evaporator fans run, rotate the right way and blades are not iced or damaged (every 6 months)

Condensing unit

• Clean the condenser coil and clear debris around the unit (every 3 months)
• Check fan motors, guards and mountings (every 6 months)
• Check the sight glass for flash gas and the moisture indicator colour (every 6 months)
• Inspect pipework, joints and capillaries for oil staining, rubbing and vibration (annually)
• Check compressor oil level where a sight glass is fitted (annually)
• Record compressor current against the nameplate (annually)

Controls and records

• Check room temperature against a calibrated thermometer; adjust the probe offset if needed (every 3 months)
• Check the high temperature alarm works and alerts the right people (every 3 months)
• F-gas certified engineers: carry out the required leak check and record it in the log (annually)
• With power isolated, check electrical terminations and contactors for heat damage (annually)
• Review the site temperature records for drift or alarms since the last visit (monthly)

Mechanical ventilation with heat recovery and whole-house extract systems.

Unit

• Clean or replace supply and extract filters; reset the filter timer (every 3 months)
• Clean the heat exchanger core to the manufacturer’s method (annually)
• Check the condensate drain and trap are clear and primed; no leaks (annually)
• Clean fans and check they run quietly without vibration (annually)
• Check the summer bypass opens and closes (annually)
• Check frost protection settings and operation (annually)
• Check electrical connections and the local isolator (annually)

Ductwork and terminals

• Check ducts in cold spaces are insulated and not crushed or disconnected (annually)
• Check room terminals are clean and have not been readjusted (annually)
• Check external supply and exhaust terminals are clear of nests, leaves and blockage (annually)
• Measure flow rates at terminals on trickle and boost; compare with commissioning figures (annually)

Controls

• Test boost switches, humidistats and timers (annually)
• Check the control panel for faults or filter warnings (annually)
• Explain filter changes and boost use to the occupier and leave records (annually)