To know how a flow switch is used, you first need to know what task the switch is intended to perform in the specific system you’re talking about. The vast majority are intended to operate fully automatically unless damaged or degraded, so knowing how to use a flow switch is often more a case of knowing how to tell when it’s not functioning as it should. That will depend entirely on the role it plays in a given system.
Flow Switches on boilers
Flow switches on boilers can be found in both water and gas pipelines. For water channels, they’re generally installed to protect the boiler from operating in low/no flow states. Gas boiler flow switches are mainly used to prevent the boiler from firing before any build-up of gasses has been vented by fans via the flue.
Flow Switches for pumps
A pump flow switch is usually installed to prevent the pump from running dry in the event of a failure in the water supply. As water pumps can quickly overheat or become damaged by continued running in low/no flow situations, flow switches for pumps often function to shut down the power to the pump temporarily when it isn’t being supplied with enough liquid.
Flow Switches for shower pumps
A shower pump flow switch helps maintain water pressure being sent up through the piping and out of the shower head. They can be found on both hot and cold supply channels, and are generally mechanical.
Demand for water to the shower head causes the switch to activate and this, in turn, completes a circuit which tells the pump to begin operating. Over time, shower pump flow switches can degrade due to limescale, heat and other issues, and may eventually need replacing.
Flow Switches for heat pumps
A heat pump flow switch is often found in swimming pools and spas, where a fairly large heat pump is required to bring the water up to the desired temperature once it’s switched on, and recognises a demand for both warmth and water flow. The flow switch, in this case, works to stop the pump from operating when there’s an interruption in the water supply or when the pool is not in use.
Flow Switches for pool pumps
Pool pump flow switches perform very similarly to the function outlined above for heat pumps - the switch prevents the pool pump from continuing to run in low/no flow situations, which can cause serious damage to the component, and when the pool isn’t being used.
Flow Switches for sump pumps
Sump pump switches are typically installed to ensure that the water from a drainage system won’t overflow. Again, running a non-submersible pump dry will quickly damage it, so the switch will also help protect the workings of the pump by shutting it off if the water supply fails or the flow rate falls too low.
Flow Switches for hot tubs and jacuzzis
A hot tub flow switch also protects the pump components in spas, jacuzzis and hot tubs from overheating if the flow rate is too low. In the event of a water flow failure or an air pocket forming in the pump, the switch will open to prevent a meltdown of the pump or heating elements.
High temperature and pressure Flow Switches
High temperature flow switches are commonly used in industrial or manufacturing systems, where a continuous flow of liquids or gases sometimes needs to be maintained at temperatures up to 350 Celsius and above.
High pressure flow switches are designed and built ruggedly for use in similarly challenging applications where they’re likely to be subjected to far greater forces and flow rates from various media than would normally be found in household systems.
Sanitary and hygienic Flow Switches
Sanitary flow switches are often necessary in industries where hygiene is especially important - this might include food production, pharmaceuticals, medical and laboratory environments, or in industrial research and development where it’s important to keep the risk of contamination to a minimum.
They’re usually made from stainless steel and sometimes have completely sealed-off inner chambers housing turbine or magnetic switches.
Chiller Flow Switches
Chiller flow switches are usually installed to protect against low/no flow scenarios which can lead to freeze damage. They’re often found on industrial, commercial or institutional air-cooling systems, as well as chilling many different kinds of hot-running equipment including machine tools, medical imaging units, food and beverage production systems and more. Chiller flow switches can be either air or liquid types, depending on the compression system a given cooler is designed to use.