A motorised valve is an external component in a conventional boiler system. It controls the flow of hot water to your radiators, hot water and underfloor heating. A diverter valve motor performs a similar function but is situated inside a Combi boiler and controls only the radiators and hot water.
Motorised valves are an essential part of your heating and hot water system. The Motorised valve controls where your boiler directs the heat to :
1) only the radiators
2) underfloor heating: one zone or multiple zones
2) only the hot water cylinder
3) all or a combination of the above
What exactly is the difference between a Motorised Valve and a Diverter Motor Valve? In this blog, we’ll break it down in simple terms.
A motorised valve is a device that controls the flow of water in your heating and hot water system. It is used in central heating systems to direct water to different parts of your home. Depending on how many heating zones, or if you have underfloor heating, you may have 2 or even 5 motorised valves. A typical home will have two motorised valves – one to control hot water and one to control the heating.
1. Motor-driven mechanism: It has an electric motor called an Actuator that opens and closes the valve.
2. Two-port or three-port options:
o A two-port valve controls water flow in a single direction.
o A three-port valve allows water to flow in two different directions (e.g., to the radiators or the hot water cylinder).
3. Controlled by the programmer and thermostat: The valve works automatically based on the settings of your heating system.
When the heating or boiler is operating, the motorised valve will direct the flow of hot water to:
Heat your radiators
Your hot water cylinder for taps and showers.
Various underfloor heating zones
When your thermostat or timer tells the system what’s needed, the motorised valve moves accordingly to direct the water.
A diverter motor valve is similar to a motorised valve but works a bit differently. It is located inside the combi boilers to control only the flow of hot water and heating to the radiators.
1. Diverts water: It sends water either to your taps or your central heating system.
2. Found in combi boilers: This valve is a standard feature in combination boilers (boilers that don not use a hot water cylinder).
3. Spring-loaded mechanism: Instead of being motor-driven, it often uses a spring to switch between tasks.
Think of a diverter valve as a traffic controller inside your combi boiler. If you turn on the hot water tap, the valve directs hot water to your taps or shower. When the taps are off, it shifts to supply water to your radiators for heating.
Now that we’ve explained what each valve does, let’s compare them side by side.
Feature |
Motorised Valve |
Diverter Motor Valve |
| Location | Found in conventional heating systems ie. Regular boiler or System boiler | Found inside combi boilers |
| Function | Controls flow to radiators, cylinder and underfloor heating | Switches flow between taps and heating |
| Operation | Motor-driven | Spring-loaded |
| Complexity | Can handle multiple heating zones and heating requirements | Focused on two simple tasks |
| System Type | Used with Conventional, Regular boilers or System boilers | Standard in combi boilers. |
Knowing the difference between these valves can help you understand your heating system better. If you have a combi boiler, you’re most likely dealing with a diverter valve. If you have a traditional boiler with a hot water cylinder, you probably have motorised valves.
Valves are essential for keeping your heating system efficient and functional. If one of these valves breaks or stops working properly, you might notice:
Your radiators aren’t heating up.
Your underfloor heating zones are not heating up
Your hot water isn’t flowing to the taps.
Your heating comes on with the hot water when you do not want it to
For more information, check out Common Radiator And Central Heating Faults And 9 Common Boiler Faults
In such cases, it’s best to call a professional. At Boilergurus, we’ve fixed countless valve-related issues for our customers. Whether it’s a faulty diverter valve or a stuck motorised valve, our team knows exactly how to diagnose and resolve the problem.
1. Stuck Valve: Over time, the motorised valve can stick in one position, causing either heating or hot water issues.
2. Motor Failure: The motor might burn out, stopping the valve from moving.
3. Electrical Faults: Loose connections or wiring issues can disrupt the valve’s function.
1. Blockages: Debris in the system can block the diverter valve.
2. Spring Wear: The spring inside the valve can weaken, causing it to malfunction.
3. Seal Problems: Worn-out seals can lead to leaks.
At Boilergurus, our engineers are experts in all things heating. Whether it’s valve repairs, boiler servicing, or a brand-new boiler installation, we’re here to make your home warm and comfortable.
Our services include:
Diagnosing and repairing faulty valves.
Replacing worn-out parts with high-quality components.
Installing efficient heating systems to keep your energy bills low.
When you choose Boilergurus, you’re not just getting a service; you’re gaining a partner in keeping your home warm and your heating system running smoothly.
Understanding the difference between a motorised valve and a diverter valve doesn’t have to be complicated. To summarise:
A motorised valve is common in traditional heating systems and controls water flow to radiators or a hot water cylinder or to the underfloor heating system
A diverter valve is standard in combi boilers and switches water flow between taps and heating.
If you’re ever unsure about the valves in your system or experience any issues, Boilergurus is just a call away. With our professional boiler installation and repair services, you can trust us to get your heating system back on track in no time.
At Boilergurus, we specialise in boiler installation and repair services. If you ever need help with your heating system, don’t hesitate to contact us.
20th August, 2026
18th March, 2026
