Condensate pump guides

Record the indoor-unit model and rated cooling output. Identify the drain outlet, decide where a pump can sit below it, and measure the vertical rise and approximate total pipe length. Note bends, concealed sections and the final discharge point. If replacing an existing pump, photograph its position and connections and retain its exact model details.

These facts allow a meaningful comparison. The SK-18AE is the £59.99 wall-mounted option for AC units up to 7.5 kW, with an 18 L/h figure and 8 m maximum head. The £69.99 SK-18CE is the corner option for units up to 8 kW, with 10 m maximum head and a built-in audible overflow warning. Both are rated at 18 dB(A) or less and include a 2-year warranty.

Capacity describes the amount of condensate a pump can move, while head describes the height it can overcome. Neither should be read without context. Cooling output, humidity and operating time influence water production. Tubing, bends and horizontal distance add resistance. Maximum head is a limit rather than the recommended everyday design point, so leave margin instead of planning an installation at the published maximum.

If measurements fall close to a limit, ask a competent air-conditioning installer to verify the route. A larger headline number does not correct a blocked inlet, unsupported pipe or poor mounting position. Good selection combines sufficient performance with a body format that fits, remains accessible and can be tested.

Condensate pumps involve mains electricity and water. Isolate equipment before opening covers or touching wiring, and use a competent person for new fixed wiring. Keep gravity fall into the inlet, mount the pump level, support the discharge tube and avoid kinks or low loops. Follow the instructions for both the air conditioner and pump.

Commission the system with clean water introduced at the indoor tray. Watch it reach the reservoir, trigger the pump and leave through the final discharge. Inspect every connection, repeat the cycle and check for return flow. Where an alarm is fitted, prove the warning and any approved shutdown response. A motor noise on its own does not demonstrate successful drainage.

Dust, fibres and biological film can build up in the tray, reservoir and narrow tubing. Inspection frequency should reflect use and environment. Check accessible water-contact parts according to the instructions, keep moisture away from electrical components and test after reassembly. A clean pump connected to a blocked drain will still fail, so follow the entire route.

Investigate changes in sound, frequent cycling, slow clearing, smells or damp marks early. These signs may point to contamination, vibration, trapped air or restricted tubing. Keep a record of servicing and faults, particularly in concealed installations where a small issue may otherwise remain unnoticed until water escapes.

When water appears, isolate the equipment and check the tray, inlet, reservoir, float, outlet tube and final drain in sequence. A blockage or kink can imitate pump failure. Do not repeatedly run an air conditioner that is leaking, and do not bypass an alarm to restore cooling. Fixed electrical checks belong with a competent person.

Replacement is appropriate when the pump is damaged, the motor has failed, operation remains unreliable after correct cleaning, or the old specification no longer suits the route. Fix the underlying cause at the same time. The replacement guide provides a concise checklist and links directly to both available pumps.

The SK-18AE and SK-18CE are for air-conditioning condensate only. Boiler condensate can be warm and acidic, and boiler equipment must be approved for that specific duty. Do not use either pump as a boiler replacement. Follow the boiler manufacturer’s documentation and use a Gas Safe registered engineer where work involves the gas appliance.

Likewise, compatibility with one air-conditioning brand does not mean compatibility with every model it sells. Check the model label, manual, output, drain arrangement, available space and electrical requirements. Brand guides are starting points for those checks rather than blanket approvals.

Use category pages to understand a subject, individual guides for the detailed question, and the A–Z index when you know the search phrase but not its category. Contextual links connect related issues so a noise question can lead to mounting advice, or a leak question can lead to cleaning and replacement checks.

Once suitability is established, compare both pumps on the home page. UK next-working-day delivery is £8.99 on orders placed before 1pm on a working day. Delivery speed is useful for a failed system, but it should follow—not replace—the checks needed for a safe and serviceable installation.