What is A Boiler Condensate Pump & How Does It Work?

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Last updated: October 31, 2023

One of the most common questions about the central heating systems that we get is whether they always need a boiler condensate pump. Long story short, not all heating systems require this handy little tool. For instance, if your boiler is located above the drainage line, the gravity alone will do the job of draining the acidic wastewater. If, on the other hand, your boiler is placed below the drainage line, then you will most likely need a condensate pump to help remove the condensate liquid from your home.

But before we get into the specifics of condensing boilers and whether yours needs a condensate pump, it’s important we cover the basics first, which is what a condensate pump really is and exactly how it works.

What is a Condensate Pump and Why Do I Need One?

In the UK, all gas boilers installed after the 1st of April 2005 have to be condensing types. The same goes for oil boilers installed after 2007. Condensing boilers, whether they’re gas or oil, capture waste heat by condensing the steam (hence the name). In older types of boilers, this heat would simply go out of the flue.

While condensing the steam is very energy-efficient, the end result – which is this acidic condensate – is unhealthy both for your pipes as well as your health. And this is where condensing pumps come in.

A small electric tool that’s installed on a heating or cooling system, a condensate pump’s main purpose is to drain acidic wastewater away from the home. In essence, this is a type of a centrifugal pump that collects and disperses the waste produced by the condensation from a heating system, which includes both gas and oil boilers. A typical example of using a condensate pump is in homes where the boiler has been relocated to the cellar or basement. Since gravity can’t do its job here, which is move this wastewater to the drainage system at ground level, using a condensate pump is a must.

To conclude, whether your central heating system needs a condensate pump or not depends on whether the system is able to move the condensate waste water to the drainage system on its own. If your boiler is situated so that the condensate liquid cannot be drained away by gravity, you will have to install a condensate pump.

If you have a small apartment, don’t worry – condensate pumps are compact electrical tools that are designed specifically to move the toxic liquid away from your home. And because there’s only a relatively small amount of condensate involved in all systems, the pump and its tank are compact and easy to fit.

Related Read: How To Drain A Central Heating System

How Does a Condensate Pump Work?

Okay, so the condensate pump drains the toxic wastewater away from your home so that it doesn’t corrode your pipes and negatively affect your health. But exactly how does this small tool manage to do that?

It’s pretty simple actually. Designed to run intermittently, condensate pumps come with a collection tank (usually 2 litres) where captured liquid from the boiler can accumulate. Once the condensed water in the collection tank reaches a certain level (which is set by the manufacturer), a float switch is activated. The moment this happens, the impellers start spinning, pumping the liquid out of the tank into the sewage system, leaving room for more condensate liquid in the tank to accumulate.

While some condensate pumps come with a one-stage switch, others come with two. In this case, as condensate water rises to the designated first stage, the pump is activated. If the waste water continues to rise above the first stage either because the pump has failed to activate or because the discharge is blocked, a second stage is engaged where the pump shuts down and/or the alarm is triggered.

All condensate pumps run intermittently to save energy. Generally, they operate for a minute or two at a time, so they’re very energy-efficient.

How Much Does it Cost to Fit a Condensate Pump?

The cost of installing a new condensate pump is usually between  £150 to £200. The final price depends on multiple factors though, including the brand and model of the pump you choose, whether you have the required condensate pipework installed in your home and whether you need a soak-away unit fitted. Of course, there is the number of work hours to take in consideration as well, which varies based on your location, who you hire for the job and how much work is required to complete the installation (normally, an hourly rate ranges between £40 to £60).

If you’re wondering about the top manufacturers of condensate pumps, we can recommend Grundfos, Saniflo and Stuart Turner. These three brands are well-regarded in the condensate pumping industry because they all offer quality design and engineering. While you won’t make a mistake with any of their pumps, the following three models are some of the best that the market has to offer:

  • Grundfos Conlift 1LS Automatic: with a stainless steel motor shaft, safety overflow switch, and operation test button, this model is truly one of the best out there. Aside from being perfect for collecting condensate waste from any condensing boiler, the Grundfos Conflit 1LS is great for air conditioning units, refrigerators, evaporators and air humidifiers.
  • Saniflo Sanicondens Pro: with a 60W motor, 2-litre tank and 6-meter flexible discharge pipe, this pump is quite the powerhouse. But don’t worry, it’s not bulky; quite the opposite, in fact as it’s specially designed for condensing boilers.
  • Stuart Turner Wasteflo BC 3 : designed to quietly and efficiently remove condensate water, the Wasteflo BC3 is also specially made for condensing boilers. Supplied with a 2-litre tank, it works with any condensing boiler you might have.