Finding the faulty

5.     HOT WATER CYLINDER

When the hot water tap is open the pipe at the top of the cylinder should get hot and cold water should enter at its bottom. Otherwise there is an Air Lock in the system.

6.     ROOM THERMOSTAT

Select central heating only on the timer. The boiler should fire at maximum setting and off at minimum setting

7.     CYLINDER THERMOSTAT

Select Hot water only on the timer. The boiler should fire at maximum setting and off at minimum setting

8.     PROGRAMMER

It should read the correct time of the day. Make sure it has power.

9.     RADIATOR

Vent the air, until warm water comes out. The radiator should warm up.

10.  THERMOSTATIC RADIATOR VALVES

Remove the sensor head from the valve body to test the valve.

Precautions to avoid expensive repair bills

Electrical appliances must have the correct fuse in the plug and, if it blows, a higher rated fuse should never be fitted. The flexes should be short, undamaged and continuous from the plug to appliances.

Gas appliances should be checked or serviced annually by an installer registered with Gas Safe. All gas appliances need a good supply of fresh air for safe operation .Don't block the ventilators in the rooms where gas appliances are installed. Check that chimney and flues are not blocked.

To prevent water damage to your property in an emergency, make sure you know it location and have easy access to the water mains stopcock. The stopcock is usually on the pipe which enters your property, front garden, basement, etc. The underground stopcock need a long arm key, available at plumber€™s merchants. When closed there is no cooking water supply in other words kitchen sink cold water supply will be off but bath room may have supply from the storage tank. Inspect the tanks for corrosion. Insulate all exposed pipes and tanks. Make sure they are on solid support and some warmth can reach the water tanks. If necessary open the loft access.

When you are away from home or on holiday during winter months.

Types of Central Heating Systems:

OPEN &

CLOSED

Closed Domestic Central Heating System

 The circulating central heating water is at a pressure about 1.2 Bar, the system is closed to maintain the pressure. A closed system must have a pressurised Expansion Vessel Filling Point  By Pass Valve and a Pressure Relieve Valve. more  

Filling Point: Normally, the cold water supply is taken from the house cold mains supply via a no return valve. The filling point is connected to the cold water supply by a filling loop, while filling and must be removed after filling to the required pressure. Most Combination Boiler systems are fitted as closed systems.

By-pass Valve: When the main circuit is closed or restricted, the by pass or the bypass valve will ensure water still to circulate through the heat exchanger, preventing the boiler from over heating with water. If there is a by-pass-valve the pump's pressure will open the by-pass-valve and provide flow through the heat exchanger.

Expansion Vessel:  The vessel has a flexible neopren (synthetic rubber) diaphragm inside separating the water and Nitrogen. The nitrogen is pre charged at about 0.7 to 1 bar is on one side of the vessel. When the water in the system is heated it will expand and the diaphragm is forced out of shape into pressurized part of the vessel to accommodate the increased volume of water.

Pressure Relive Valve: When water temperature is above 100C, it expands very rapidly and by becoming steam it can exert very high pressure. In a closed system, it can cause pipe work to burst or leak at joints. The pressure relief valve prevents damage by releasing the hot water safely. This is a SAFETY device and should be properly fitted and serviced. It is spring loaded to be normally closed and opens only when the system pressure exceeds its preset value, about 3 bar. Domestic central heating boilers

Central Heating Boilers

Gas Central heating Boilers

Solid Fuel Central Heating Boilers

Oil Central Heating Boilers

Open Flue Central Heating Boiler

Balanced Flue Central Heating Boiler

Fan Assisted Central Heating Boiler

Back Central Heating Boiler

Wall Mounted Boiler

Free Standing Boiler

Boiler Efficiency

 SEDBUK

 Seasonal Efficiency of Domestic central heating Boilers in the UK is the average annual efficiency achieved in typical domestic conditions, making reasonable assumptions about pattern of usage, climate, control, and other factors. It is calculated from the results of standard laboratory tests together with other important factors such as boiler type, ignition arrangement, internal store size, fuel used, and knowledge of the UK climate and typical domestic usage patterns.

Gas Boilers

There are two type of gas fuel for boilers; Natural Gas or Piped Gas and Liquid Petroleum Gas (LPG).

 Natural Gas Central Heating Boilers:

 Given that piped natural gas is available for cooking, the natural gas boilers are the cheap boiler to install and maintain. They don't require fuel storage facilities and can be automatically controlled hence has lower running cost. more

LPG Central Heating Boilers:

The LPG central heating Boilers are normally adapted from the standard Natural Gas Boilers, often only require smaller main burner jets because LPG supply pressure is higher than natural piped gas. Running Cost of LPG gas boilers are similar to oil boiler. Like oil boiler the LPG gas boiler also need a storage tank and a fuel feed line from the tank to the boiler. Types of Gas Boilers Back Boiler, Free Standing Boiler,Wall Mounted Boiler, Combination Boiler, Condensing Boiler. more 

List of Competent Persons who can service or repair gas central heating  boilers and certify compliance to Building Regulations is maintained by CORGI for more information see http://www.trustcorgi.com

Solid Fuel Central Heating Boilers 

Solid fuel boilers were the first type of domestic heating boilers used in the 50s central heating system. They were introduced by coal utilization council. However due to the need for stoking, coal lost ground to automatically controllable gas and oil. Many solid fuel boilers are now multi-fuel and can burn both wood and coal, but the heat output of the boiler depends on the type of fuel. Types of Solid Fuel Boilers, Boilers and Room Heaters, Free Standing Cookers. more

List of Competent Persons who can service or repair solid fuel boilers and certify compliance to Building Regulations is maintained by HETAS for more information see www.hetas.co.uk

Oil Central Heating Boilers

The oil must be stored in an oil tank. The risk of environmental damage caused by the oil spillage from the oil tank, feeding pipe line and the boiler will need to be considered. The oil tank must be protected as much as possible from the cold weather because if the oil become very cold it becomes too thick to flow through the feeding pipe line known as waxing. Oil boiler are best in an outside boiler house ,because oil boilers make some noise and smell. An oil fired boiler can be controlled just like a gas fired boiler, all forms of automatic controls can be used. Types of Oil Boilers Free Standing Combination Boiler.  more

List of Competent Persons who can service or repair oil boilers and certify compliance to Building Regulations is maintained by OFTEC for more information see www.oftec.org.uk

Central Heating Controls

Controls provide Comfort and reduce the running expenses of the central heating system. In home central heating there are three main types of controls namely Temperature, Time and Heated water Distribution. 

Temperature Controls

 In Home Central Heating Thermostats are used to control temperature. A Thermostat senses the change in temperature and then Open or Close electrical circuits as required, in response to the change. more 

Boiler Thermostat

  The Boiler thermostat controls the temperature of the water in the Boiler. If it is set to 80 then when the water temperature reached, the thermostat will cut off power the gas valve and turn off the burners.

Room Thermostat

The Room thermostat or Room stat is used to detect changes in the temperature of the air in the room. If the required temperature of the room stat is set to 20C then when the room's air temperature reached the set value the room stat will turn off power to the boiler and pump. This way it will maintain the comfort level and also note it stops the boiler burning gas, hence reduce the gas bill.

Cylinder Thermostat

Cylinder thermostat or cylinder stat is fitted on to the hot water cylinder to sense the temperature of the hot water. When the set temperature is reached, depending on the system design the cylinder stat will divert the hot water from the boiler or turn off boiler and pump.

Frost Thermostat

A Frost thermostat or Frost stat is in fact a room stat with the required temperature set at value 5 C and wired in such a way the it can over run all controls and turn on the central heating by switching on the boiler and pump even when the central heating system is switched off. Hence save the boiler and pipe work are protected from frost damage.

Thermostatic Radiator Valves (TRVs)

A thermostatic radiator valve is fitted on a radiator in place of the hand control. It has

a temperature sensor built-in to the valve. When the room temperature reaches the set value on the valve, it mechanically closes valve.

Time Controls

The purpose of the time control is to switch ON and OFF central heating when it is required. Thus reducing the running cost of the central heating system and gas bill. Time Switches or Timers. These are simple power ON/OFF devices. They can switch the central heating ON and OFF once, twice even many times.

Programmers

 We may not want heating at the same time as the hot water. A programmer can turn on/off hot water and central heating separately. 

Heated Water Distribution Controls

 We require the Central Heating System to provide heating for different zones or areas (for example first floor and ground floor) at different times or at different temperatures from each other, this is accomplished by fitting distribution controls. 

Zone Valves

 Zone Valve consist of a electric motorised valve and a spring. When the valve is powered the valve open and the power is off the spring closes the valve. For example we may want the bed rooms only heated an hour before we get up and then again an hour before going to bed. This can be achieved by having Zone valves on the bed rooms pipe work connected to a timer switch. 

Diverter  Valve

A diverter valve can divert the heated water from the boiler into two circuits/pipe works or zones. Usually between hot water circuit and central heating circuit.