Electronic Controls


What is a room thermostat?

A room thermostat simply switches the heating system on and off as required. It operates by sensing the air temperature, switching on the heating when the air temperature falls below the thermostat setting, and switching it off once this set temperature has been reached. Turning a room thermostat to a higher setting will not speed up the heating of the room. The speed of heating up is determined by the design of the heating system; eg, by the size of boiler and radiators.

Neither does the setting affect how quickly the room cools down. Turning a room thermostat to a lower setting will result in the room being controlled at a lower temperature level, and saves energy.

The heating system will not operate if there is a time switch or programmer that has switched it off.

The way to set and use your room thermostat is to find the lowest temperature setting that provides your own comfort level, and then leave it alone to do its job. This is best achieved by first setting the room thermostat to a low temperature – say 18 °C – and then turning it up by one degree per day until your comfort level is reached. Once this comfort setting has been established then you do not need to adjust the thermostat further. Any adjustment above this setting will waste energy and cost you more money.

If your heating system is a boiler with radiators, there will usually be only one room thermostat to control the whole house. But different temperatures in individual rooms can be achieved by installing thermostatic radiator valves (TRVs) on individual radiators. If you don’t have TRVs, you should choose a comfort setting that is reasonable for the whole house. If you do have TRVs, you can choose a slightly higher setting to ensure even the coldest room is comfortable, then eliminate any overheating in other rooms by adjusting the TRVs.

Room thermostats need a free flow of air to sense the temperature, so they must not be covered by curtains or obstructed by furniture. Their performance will be adversely influenced by other heat sources; eg, electric fires, televisions, wall or table lamps.

What is a cylinder thermostat?

A cylinder thermostat switches on and off the heat supply from the boiler to the hot water cylinder. It operates by sensing the temperature of the water inside the cylinder, switching on the water heating when the temperature falls below the thermostat setting, and switching it off once this set temperature has been reached. Turning a cylinder thermostat to a higher setting will not speed up the water heating. The speed of water heating is determined by the design of the heating system; eg, by the size of boiler and the heat exchanger inside the cylinder.

The water heating will not operate if there is a time switch or programmer that has switched it off. And the cylinder thermostat will not always switch the boiler off, because the boiler is sometimes required to supply heat to the radiators.

Cylinder thermostats are usually fitted between one quarter and one third of the way up the cylinder. The cylinder thermostat will have a temperature scale marked on it, and it should be set at between 60C and 65C, then left to do its job. This temperature is high enough to kill off harmful bacteria in the water, but raising the temperature of the stored hot water any higher will result in wasted energy and increase the risk of scalding.

If you have a boiler control thermostat, it should always be set to a higher temperature than that of the cylinder thermostat. In most boilers, a single boiler thermostat controls the temperature of water sent to both the cylinder and radiators, although in some there are two separate boiler thermostats.

What is a programmer?

Programmers allow for “On” and “Off” time periods to be set. Some models switch the central heating and domestic hot water at the same time, whilst others allow for independent switching of the domestic hot water and heating at different times.

Set the “On” and “Off” time periods to suit your own life style. On some programmers you must also set whether you want the heating and hot water to run continuously, run under the chosen “On” and “Off” heating periods, or be permanently off.

The clock on the programmer must be kept at the correct time. Some types have to be adjusted in spring and autumn at the changes between Greenwich Mean Time and British Summer Time.

Your programmer may provide additional features for temporary adjustments of the heating programme; eg, “Override”, “Advance” or “Boost”. These are explained in the manufacturer’s instructions.

The heating will not operate if the room thermostat has switched the heating off. And, if you have a hot water cylinder, the water heating will not operate if the cylinder thermostat detects the hot water has reached the required temperature

What is a programmable room thermostat?

A programmable room thermostat is both a programmer and a room thermostat. A programmer allows for “On” and “Off” time periods to be set to suit your own life style. A room thermostat operates by sensing the air temperature, switching on the heating when the air temperature falls below the thermostat setting, and switching it off once this set temperature has been reached. So a programmable room thermostat lets you choose what times you want the heating to be on, and what temperature should be achieved while it is on. It will allow you to select different temperatures in your home at different times of the day (and days of the week) in order to match the heating to your particular requirements.

Turning a programmable room thermostat to a higher setting will not speed up the heating of the room. The speed of heating up is determined by the design of the heating system; eg, by the size of boiler and radiators.

Neither does the setting affect how quickly the room cools down. Turning a programmable room thermostat to a lower setting will result in the room being controlled at a lower temperature level, and saves energy.

The way to set and use your programmable room thermostat is to find the lowest temperature settings that provide your own comfort level at the different time periods you have chosen, and then leave it alone to do its job. This is best achieved by first setting low temperatures; say 18°C, and then turning them up by one degree per day until your comfort level is reached. Once the comfort settings have been established then you do not need to adjust them further. Any adjustments above these settings will waste energy and cost you more money. If your heating system is a boiler with radiators, there will usually be only one programmable room thermostat to control the whole house. But different temperatures in individual rooms can be achieved by installing thermostatic radiator valves (TRVs) on individual radiators. If you don’t have TRVs, you should choose a comfort setting that is reasonable for the whole house. If you do have TRVs, you can choose a slightly higher setting to ensure even the coldest room is comfortable, then eliminate any overheating in other rooms by adjusting the TRVs.

The clock on the programmer must be kept at the correct time. Some types have to be adjusted in spring and autumn at the changes between Greenwich Mean Time and British Summer Time.

Your programmable room thermostat may provide additional features for temporary adjustments of the heating programme; eg, “Override”, “Advance” or “Boost”. These are explained in the manufacturer’s instructions.

Programmable room thermostats need a free flow of air to sense the temperature, so they must not be covered by curtains or obstructed by furniture. Their performance will be adversely influenced by other heat sources; eg, electric fires, televisions, wall or table lamps.

What quality standard applies to the MPE motorised valve range?

All MPE motorised valves are manufactured under BS EN ISO 9001:9002.

What do power extra motorised valves do?

Motorised valves are actuated by room and cylinder thermostats and control the flow heating system water according to the requirements of either your hot water cylinder or central heating system.

What is the difference between 2 and 3 port motorised valves?

Two port valves have one inlet and one outlet and simply allow the system heating water to flow straight through (to the controlled circuit) or stops it on demand.

The three port valves have one inlet and 2 outlets, and therefore have the ability to direct the system heating water to either the hot water circuit or the central heating current or both simultaneously on demand.

What happens if your Power Extra motorised valves fail to function correctly?

Remove the actuator unit (two screws), and rotate the valve spindle manually. If the spindle turns freely, it is likely a fault lies within the actuator head which can be easily replaced (four wires / 2 screws).