[How to] How and why should you clean the condensate removal pump in your air conditioning unit?
Indoor air conditioning units tend to be equipped with a mini condensate removal pump, which removes the liquid formed by condensation in the heat exchanger. These pumps naturally foul over time. But why?
Biofilm: a universal problem
Biofilm is enemy number one – and the leading cause of fouling in a condensate removal pump. No matter what the conditions, it’s impossible to avoid the build-up of biofilm. It forms when bacteria act in symbiosis to create the environmental conditions they need to multiply. This so-called “biological cocoon” consists of a thick, multi-cell layer that’s viscous when wet and sticky when dry.
Biofilm might be the main culprit, but it’s important not to overlook other causes, depending on where the unit is situated:
Dust and particles suspended in the air, which end up being deposited on the heat exchanger.
Some aerosols and other types of lacquer that dissipate in the air (such as at hair salons).
Cellulose (paper) dust, which is present in large amounts in libraries and bookshops.
Tobacco smoke (micro-particles build up in a thick layer).
Smoke from cooking oils and fats, especially in open-plan kitchen spaces (see our example from a chocolate factory).
The above list isn’t exhaustive, but it gives an idea of the sheer range of particles that are sucked into an air conditioning unit during cooling.
Protect the detection unit!
The main reason for maintaining a pump is to make sure that the level detection unit, located in the tank, is working as it should, so it can control the suction correctly.
Some conventional detection units, such as float-type systems, operate mechanically and are especially sensitive to fouling. The float can become stuck to biofilm at the bottom of the tank, which has dried out after spending the winter in heating mode – and therefore producing no condensation. Aerosols, lacquers and smoke from oils and fats can have the same effect. The unit can also be prevented from rising by accumulated dust and particles. And if the detection unit gets stuck, the pump doesn’t come on – and that’s when leaks can start!
Our Si-30 Detect+ pump is equipped with a capacitive, non-mechanical detection unit that measures condensate levels through contact. This system is more resilient to fouling, especially in premises where the air is thick with particles (such as hair salons, kitchens and factories). Its hard-wearing design means it only needs to be maintained once a year, as opposed to a float-type system, which has to be cleaned every two months!
Next, open the detection unit tank and rinse it using the same liquid (or water) to remove all the particles. Make sure the bottom of the tank isn’t sticky, that the float is clean and free from sticky residue, and that it slides smoothly. The same cleaning and maintenance procedure also applies to capacitive detection systems. Although they don’t contain any sliding mechanical parts, they will still benefit from thorough cleaning!