Home Improvement Articles

The Mains pump…
This is the element that will do almost all of the work eliminating the water from below the basement floor, it will be required to work night and day, week in week out, year after year.
For this reason the pump must be a real work horse, if the pump(s) fail the basement could flood, everything depends on it so the most important thing it=s to ensure reliability.

These are the features that you should look for in a reliable pump :-

The float switch.
This should never be the trailing arm type, these can get caught on the side of the sump liner, or in tangled with another pump in a multi-pump system causing the pump to either not come on when it should or not go off when it should and thereby causing the motor to burn out.

Diaphragm pressure switches avoid this problem but the diaphragm can become brittle with age and require higher and higher water pressure to activate them so avoid these too.
The best type of float switch is one where the float moves vertically either on a spindle or within a cylinder.

The pump body.
Avoid plastic at all costs, plastic pumps can get hot and when working relentlessly the heat can cause a thermal cut out to activate switching the pump off or if there is no thermal cut out causing the pump to fail. Plastic pumps are also indicative of cheap manufacture and the chances are the pump motor will also be cheap.
The best pumps come with either a stainless steel or epoxy coated cast iron body. These pump bodies are expensive and are a good indicator of the overall quality of the pump. Metal bodies dissipate heat much more efficiently than plastic and therefore are suited to the work-horse lifestyle that is required of them.

The pump motor.
You are not going to get to see this as it will be sealed inside the pump body but look at the performance specification. you should choose a pump that will discharge 2 – 3 liters per second to an eight foot head and ensure that there is adequate pumping capacity at the height required for your particular basement. A 50 mm outlet will be required to cope with this type of volume so anything that has a half inch or one inch outlet should be avoided.
Pump motors either run in a bath of oil, sealed inside the pump or in air. Both are reliable but the oil bath pump has become more outdated due to advances in pump design. If a seal goes and the oil leaks out you are going to be pumping oil into the environment or your septic tank which is not good. Oil filled pumps also use more electricity for the same performance as an air filled pump due to the inertia of the oil itself.

The pump stand.
Never site a pump directly on the floor of the sump chamber. some pumps come with a good pump stand to keep the impeller out of the silt than can collect in the bottom of the sump chamber. Either make sure that the pump has its own built in stand (minimum 50mm) or that the sump system includes one. if noise is going to be an issue the oil filed pumps do tend to make more noise for the same level of performance, this is a result of the pump having to work harder, burn more energy for the same work done and more precision engineering that the more modern air-filled pumps have.

Back up pumps.
So what happens if the primary pump fails or there is a power cut?
There should be at least one back up- pump that can take over in such an eventuality. Battery pumps are the most common and these are essential in the event of a mains power failure but they tend to be less powerful and less reliable than a mains pump. The best combination is a twin mains pump so that another mains pump comes on in al failure events other than a power cut, plus a battery back up pump to protect during the power outage.
Some pumping systems have a back up pump that can run off both mains and battery so a twin pump system is all that is required if you have one of these as your back up pump.

i will look at back up pumps in more detail in my next article.
Meanwhile click the anchor text link at the end of this sentence if you want to ask me a question about sump pumps or cellar conversions

Raymond Foulkes, the author of this article has served for several years as the elected Technical officer of the British Structural Waterproofing Association (BSWA), in this capacity he was the primary author of the BSWA design guide ‘A Guide to Waterproofing Existing Basements’ a publication that has be come the benchmark text for the industry. He offers consultancy / expert witness work as well as a full contracting service see http://www.polycrete.co.uk and a unique basement waterproofing system for DIY basement waterproofing.

In the mid 1990’s Ray Foulkes pioneered the use of bespoke sump and pump systems together with proprietary underfloor perforated drainage channels for basement waterproofing, a method that has now become commonplace throughout the industry.