Project Description

Can We Help Repair Your Home Heating System?

Heating Systems, Hot Water Faults & Repairs

There are a number of heating system faults which could result in no hot water from taps and showers, or cold radiators throughout your home. We have separated this section from boiler breakdowns and repairs as some types of heating systems include many external components, separate to the boiler, that can have an effect on your heating and hot water if they begin to malfunction.

Heating system parts often fail in the autumn or winter after long periods of inactivity in the summer months. Your heating should be switched on for an hour at regular intervals throughout the summer to ensure that it still functions correctly.

What are the Main Types of Heating System?

Other than combination boilers, there are two common types of heating systems found in modern homes: S plans and Y plans. The one fundamental difference between the two is that a Y Plan uses one 3-port motorised valve to distribute the heat to your radiators and/or hot water cylinder, while the S plan uses two 2-port motorised valves. Motorised valves (or zone valves) open and close depending on whether you switch on your heating or hot water.

Both S and Y plan systems rely on a system or conventional boiler and a vented or unvented hot water cylinder to supply heating and hot water. Below we have included diagrams of both a Y and S plan system.

Y plans are a slightly outdated system and their main limitation is that they only allow for one central heating zone. S plans can allow for heating systems with multiple zones as their individual 2-port valves can be used to supply heat to each circuit.

Another drawback of the Y plan is that if the 3-port valve fails then the customer will have neither heating nor hot water. This is not true with an S plan, as the heating and hot water are controlled via two separate valves.

These key points make S plans the system of choice for all new installations, however there are still many Y plans in existence and it is important for engineers to know how they work in order to carry out repairs. We will always look for the cheapest and easiest solution for the customer and will not suggest a system upgrade unless absolutely necessary.

Expert Help

How Are Heating System Faults Diagnosed?

Locating the source of a fault on a central heating system can be a difficult and daunting task without the correct knowledge, training, and equipment. A fault on an electrical component such as motorised valve, programmer, or thermostat is diagnosed using an electrical multi-meter. Employing a professional engineer will save you a lot of time and avoid any further damage that could occur if one was to attempt a repair oneself.

ASP Plumbing and Heating Services have the knowledge and experience to diagnose heating system faults quickly and efficiently. Please do not hesitate to get in touch on 020 3858 0277 or via our contact form if you have any queries relating to heating or hot water repairs.

Common Heating and Hot Water System Faults

Below we have outlined some of the main causes of heating and hot water system faults:

Motorised valves (or zone valves) are responsible for diverting heat to your hot water cylinder or radiators when either is selected on your programmer. It is not uncommon for the valve motors to stick or burn out, which will prevent the boiler from firing when either hot water or heat is called for. On Y plans, a symptom of a faulty 3-port valve could be the radiators heating up when only the hot water is switched on, or neither the heating nor hot water working at all. In an S plan, if the boiler fires up for heating but not hot water (or vice versa), one of the zone valves could have failed. Zone valve motors are easy to change but require rewiring, so it is best to leave it to a professional. Rarely, the actual valve will fail or become jammed, which requires the draining of the heating system in order to replace. This is a more time-consuming repair than just replacing the motor.

Circulating pumps are responsible for pumping the water around your central heating or hot water circuits. Over time, pumps can seize, burn out, or get blocked up with sludge. Pump faults are relatively easy to diagnose. If your boiler fires up then immediately cuts out due to overheating, the first port of call would be to check the pump. If the pump has a power supply going to it but isn’t running, then the chances are it will need replacing.

The programmer/timer is the control unit that is used to switch your heating and hot water on or off. If the display of the programmer goes blank, or if the timer is behaving erratically, then in may call for a replacement. Room thermostats, especially older manual types, can become inaccurate over time or even stop working altogether. If your heating doesn’t switch on but all other components seem to be working correctly then your thermostat could be at fault. Newer digital thermostats are more accurate and are favoured over manual thermostats. Many smart thermostats have a timer and a programmer all in one. For more on smart thermostats and heating controls, click here.

Faulty hot water cylinder thermostats can result in poorly regulated hot water or no hot water whatsoever. If you are getting no hot water and you are confident that your programmer and motorised valves are working, then it could be your cylinder thermostat. Faulty hot water thermostats can be easily diagnosed using a multi-meter and are cheap and easy to replace.

The build-up of sludge and debris in heating system pipework can cause blockages which leads to poor circulation, pump failure, and poor heat output from radiators. Having your heating system flushed or installing a magnetic system filter is sometimes a necessary repair on particularly dirty systems to restore them to full working order. See our section on heating system flushing for more details.

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We Can Get Your Heating System Working Well

Keep a reliable flow of hot water, when you need it. We can help. Use our contact form or call now 020 3858 0277.
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