Heating FAQ

  1. What is a Sealed Heating System?
  2. What is an Open Vent or Gravity Heating System?
  3. What are Smart Heating Controls?
  4. What size boiler do I need?
  5. What is Inhibitor?
  6. Do I need a Magnetic Filter?
  7. How can I improve boiler efficiency and reduce gas usage?
  8. What is Weather Compensation?
  9. What is a Outdoor Sensor for?
  10. What are Modulating Controls?
  11. Does my heating system suffer from corrosion?
  12. What is a Condensing boiler?
  13. What causes sludge in heating systems?
  14. Should I leave my heating on 24/7?
  15. Why do I have a noisy plumbing system?
  16. What is a Powerflush?
  17. Why have a Powerflush?
  18. Why are some radiators cold?
  19. What are Thermostatic Radiator Valves (TRV)?
  20. Why is my radiator cold at the top and hot at the bottom?
  21. Why is my radiator hotter at the top than at the bottom?
  22. Why are some of my radiators hotter than others?

 

1. What is a Sealed Heating System?

Wet central heating systems are either Open Vented or Sealed. A sealed heating system is sealed to the atmosphere: it is a closed circuit, and is pressurised to the designed pressure (typically 1 bar). As the preferred choice, a sealed system is more efficient and is less likely to suffer from air locks, air ingress, sludge and corrosion.(top)

2. What is an Open Vent or Gravity Heating System?

Wet central heating systems are either Open Vented or Sealed. The older Open Vent systems are so called as they are vented to the atmosphere. A small Feed and Expansion (F&E) tank is used to fill and pressurise the heating system. As the name suggests, the F&E tank also accommodates the expansion from the heating system.(top)

3. What are Smart Heating Controls?

Smart Heating Controls or Smart Thermostats enable a heating system to be controlled remotely via a smart phone, tablet or desktop computer (PC). This enables more convenient and efficient control of the heating system.(top)

4. What size boiler do I need?

It is extremely important to have a correctly sized boiler. This needs to be matched to the heat loss of the property together with the size and type of heat emitters (radiators or underfloor heating). If it is undersized, the property may be cold in the Winter. If it is over sized, it will be inefficient, and the boiler will continuously cycle on and off… (top)

5. What is Inhibitor?

The use of inhibitor is greatly misunderstood throughout the UK, and it’s use may well have a negative affect on the heating system and cause more harm than good! Inhibitors (e.g. Fernox F1, Sentinel 100, Adey MC1) are used to reduce corrosion, but it’s just not that simple; there is no single-solution for all systems. There are many factors to consider, for example, conductivity, PH (acidity/alkalinity), hardness, etc. All this depends on the make-up of the system, whether the boiler has an aluminium, copper or stainless steel heat exchanger, steel radiators, underfloor heating, or both, sealed or open vent system, etc. See our section on Corrosion in Heating Systems(top)

6. Do I need a Magnetic Filter?

A magnetic filter will help maintain a clean heating system. It helps filter out both magnetic (steel, rust) and non-magnetic (dirt) debris from the heating system. It also offers protection to the boiler heat exchanger. We would always recommend installing a good quality filter; indeed many boiler manufacturers now insist one is fitted.(top)

7. How can I improve boiler efficiency and reduce gas usage?

For a new system, a modern high efficiency boiler with advanced compensation controls will make a tremendous difference in performance, efficiency and overall comfort! Most existing boilers can be upgraded with advanced compensation controls to replace standard on/off controls. Again this will make a big difference in efficiency and comfort levels.(top)

8. What is Weather Compensation?

A Weather Compensation heating system modulates the boiler according to the outdoor temperature; when the weather is very cold, the boiler will increase the flow temperature (hotter radiators). Conversely, if the weather is mild, the boiler will run at a lower temperature. The outdoor temperature is monitored through an outdoor temperature sensor or via an online weather station. This advance information enables the boiler to quickly react to the change any temperature changes before it affects the indoor temperature. A weather Compensation Heating System is much more efficient than traditional heating systems using room thermostats with on-off controls.(top)

9. What is a Outdoor Sensor for?

An outdoor sensor monitors the outside temperature. This information is fed back to the heating boiler to establish how low a flame it can use to satisfy the heating requirements. This ensures the boiler can operate as efficiently as possible.(top)

10. What are Modulating Controls?

Modulating Heating Controls are considerably more efficient than standard on-off heating controls. They communicate (two-way) with the boiler so it only burns the minimum amount of gas to satisfy the heating demand. The modulating control will normally adjust the boiler according to the difference in room temperature and the set-point (desired temperature).(top)

11. Does my heating system suffer from corrosion?

Simple answer is yes! All wet heating systems corrode; the expertise is to analyse and understand the chemical process, and ultimately reduce the corrosion process as much as possible. Corrosion affects efficiency and performance, and badly designed or poorly maintained heating systems will degrade over time; even in as little as a few weeks! See our section on Corrosion in Heating Systems(top)

12. What is a Condensing boiler?

Condensing boilers make use of the latent heat from the flue gases to improve overall boiler efficiency. Instead of discarding the hot flue gases straight to atmosphere, they recycle the hot gases to reuse the heat. The water vapour condenses and produces the by-product condensate which is discarded to waste. Since April 2005, Building Regulations stipulate the all new domestic boilers should be condensing boilers.(top)

13. What causes sludge in heating systems?

Sludge, caused by corrosion within a heating system is due to poor system design or poor maintenance. Sludge will reduce performance and efficiency, and the cause should be investigated as soon as possible.(top)

14. Should I leave my heating on 24/7?

This really depends on the property, amount of insulation, the thermal mass, the type of heating system, and the heating controls. Certainly with a new system that we would install, the heating will effectively be on 24/7, and the desired temperature will determine if the boiler actually needs to fire. For example, you may set the desired temperature to 21C during the day and 16C at night. If the property is well insulated and the indoor temperature remains above 16C, then the boiler will not fire. Modern heating controls enable far superior control over time and temperature settings when compared to a standard programmer with room stat.(top)

15. Why do I have a noisy plumbing system?

Noise in your plumbing system can be caused by various reasons, but is quite often attributed to the velocity of the water running through the pipes. By reducing the velocity you can reduce the noise. It could be that the system has been designed with undersized pipes or that there are faulty components (stop valves, ball valves, etc) which should be replaced or adjusted as necessary. (top)

16. What is a Powerflush?

Power flushing is the process by which heating systems are forcibly cleansed using water at high velocity, but low pressure, so that no physical damage is caused to the system. The process can be made even more effective with the addition of powerful cleansing and mobilising agents to breakdown the sludge and remove limescale build up. (top)

17. Why have a Powerflush?

A Power flush is often carried out to restore a heating system to optimum efficiency. It can remove blockages, sludge, limescale and corrosion deposits. When carried out properly and thoroughly, radiators will heat up quickly (without cold spots) and the whole heating system will run more efficiently and quietly.
A clean and protected system improves the boiler efficiency, helps the pump and diverter valves to last much longer and reduces corrosion. (top)

18. Why are some radiators cold?

If some radiators do not get hot, it may be that the system needs balancing. The hot water will follow the path of least resistance and may bypass some areas of the heating system, if not correctly balanced. This may be due to a blockage in the pipework or simply that other radiator are taking all the heat! Reducing flow to hotter radiators may encourage other area of the system to heat up. This tends to be an itterative process by adjusting the lockshield valves, but should result in all radiators warming up at a similar rate. (top)

19. What are Thermostatic Radiator Valves (TRV)?

Thermostatic valves control the temperature of an individual room or area. They are fitted to your radiators (one per radiator and have an internal thermostat to enable temperature control to individual rooms around your home. They can also help reduce your fuel bills by automatically adjusting the valve once the room has reached the required temperature. (top)

20. Why is my radiator cold at the top and hot at the bottom?

This usually means there is air trapped in the top of your radiator. You may want to try to bleed the radiator to release the air. If this does not help we suggest that you have your central heating checked over by an expert in case there are any underlying system problems (top)

21. Why is my radiator hotter at the top than at the bottom?

Assuming the radiator has reached operating temperature, this usually means there is a build up of sludge at the bottom of your radiator. In this situation the heating system will be operating inefficiently and should be attended to, sooner rather than later. Would would advise that the heating system is checked over in case there are underlying system problems. (top)

22. Why are some of my radiators hotter than others?

This usually means that your central heating system is incorrectly balanced. This results in the hot water not flowing evenly to each radiator. We suggest that you have an expert check your central heating system. (top)