Understanding Boiler Diverter Valves: Types, Function, and Troubleshooting
The diverter valve, also known as a three-way valve, is a crucial component of modern boilers. Its task is to direct the heat produced by the generator towards the heating system or the production of Domestic Hot Water (DHW). The valves can be categorized into two main types: Pressure Static and Motorized.
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Pressure Static Diverter Valves
Pressure static valves use a membrane to alternate the flow between the sanitary and heating circuits. Made of brass, these valves are sensitive to impurities present in the system and to limescale in the water. Despite not having a motor, they contribute to simplifying the control of the boiler’s electronic board.
Use in Muddy Installations
The lifespan of these valves is closely linked to the quality of the heating water. Systems with debris or mud can cause blockages. Common defects include: inability to activate the valve or heating of the radiators during the use of DHW. The solution is often found in replacing the valve.
Importance of Domestic Hot Water Flow
The flow of domestic hot water, i.e., how many liters per minute pass through the tap, is crucial for the proper functioning of boilers with pressure static valve. Issues such as dirty aerators or reduced network pressure can prevent the valve from activating.
Prevention of Breakdowns
Breakdowns can be prevented by using magnetic filters on the return of the boiler, preventing debris and mud from clogging the valve.
Motorized Diverter Valves
Motorized three-way valves handle the exchange of circuits differently compared to pressure static valves and are typically installed in storage boilers. The choice of the heat path, towards the boiler or the heating system, is determined by the boiler’s electronic board.
Questions and Answers on Boiler Functioning
The Boiler Doesn’t Start, No Hot Water
If the radiator works, but no hot water is coming, the problem can be resolved with simple steps. Clean the mixer’s flow breaker and the shower head holes. Make sure that the boiler pressure is maintained between 1.2 and 1.5 bar and remember to close the filling tap after use.
Radiator Heating in Summer
A radiator heating up during summer typically indicates a defective diverter valve. Closing all the radiators during the summer months can be a temporary solution, but it may cause the radiator valves to block if they remain closed for too long. The best solution is to consult a trusted technician.
Lukewarm Water
If the water is lukewarm, check if the radiators are heating up near the valves. It could be a sign that some of the heat is dispersing in the heating system instead of heating the water. Alternatively, try to slightly reduce the flow of the tap and see if the water gets warmer at lower flows. This could indicate a problem with the sanitary exchanger, especially in instant rapid boilers.
Water Alternates Between Hot and Cold
If the water suddenly turns cold when mixed, it can be caused by a limescale-clogged flow breaker or by setting the domestic hot water temperature too high. In rapid boilers, the water flow is crucial. If it drops below 6-7 liters per minute, the boiler with a pressure static valve might shut off.
Shower Runs Out of Hot Water Quickly
If the hot water in the shower runs out quickly, it could be a sign that the storage boiler is dirty with limescale or that the diverter valve is damaged. In this case, evaluate with a technician the possibility of cleaning the limescale from the storage or repairing the diverter valve, or both.
