CUSTOMER ADVICE
If you find yourself thinking, I wonder what that means - then take a look below at more information on the terminology around central heating.
WHAT IS LOW TEMPERATURE HEATING
This involves lowering the temperature of the water flowing within the radiators(flow temperature) whilst not lowering the temperature of the room. If we size a radiator correctly for it's respective room size and flow temperature we can still achieve our desired room temperature despite having a lower flow temperature through the radiators - which increases boiler efficiency.
IMPORTANT: Updated building regulations encourage systems to be designed with 55°c flow temperatures.
FIXED FLOW TEMPERATURE
This is the temperature of the water flowing from your boiler to the radiators and/or cylinder if you have one. The temperature is set at the boiler during the installation/commissioning stage and is then left alone. The boiler will always ignite to achieve this temperature of water within the system. This temperature is fixed and if you want it altered you need to manually change it by going into the settings or adjusting the correct potentiometers at the boiler. Weather compensation is a device that will alter this temperature automatically so the rads aren't as hot when the temperature outside is more mild - giving you better comfort in your home.
HEAT LOSS CALCULATION
This is where you measure the rooms within a house, measure the windows and other openings, and take note of the material used within the fabric of the building. With this info we then calculate how much heat would be lost through that room to outside when the temperature is -3 degrees. We then put a radiator in that room to replenish the heat that would be lost from that room at a worse case scenario of -3 degrees outside.
WEATHER COMPENSATION
Like we said above, we design rads to a worse case scenario outside temperature of -3 degrees. However, when it's not -3 degree's outside, the room doesn't need the same amount of heat to be replenished. Weather Compensation will sense the outside temperature and automatically adjust the flow temperature to the rads so that you get the correct amount of heat into the room to achieve your desired room temperature. This will only work if your heat loss calculation is correct and rads have been sized correctly.
If you have a fixed flow temperature (which most systems have) your rads will always be the same temperature to touch regardless of the temperature outside, which in turn at times, makes you too hot or uncomfortable within the room.
ON / OFF THERMOSTATS
These are basic room thermostat controls. You set the temperature required at your dial on the wall and the boiler will heat the rads until the room stat satisfies at your set temperature. This can cause the boiler to click on and off as it's constantly chucking out a fixed flow temperature to the rads. If you had weather compensation for example, it would adjust the flow temperatures from the boiler accordingly to keep the boiler ticking over at a lower more efficient rate and keep the room temperature at a more even comfortable feel. What tends to happen otherwise, is with a fixed flow temperature the room will often over shoot the desired room stat temperature (boiler goes off) making it feel too hot in the room, the room then cools below the set room stat temperature (boiler comes on) and the process repeats. It's this on / off that causes inefficiency at the appliance.
CONDENSING BOILERS
Condensing boilers were introduced from 2005. They are designed in such away that they extract more of the heat that is normally lost out of the flue to outside when the gas is burnt (combustion process). If we get the flue gasses to condense as much as possible we can then reuse this normally lost energy and therefore increase the efficiency of the appliance. For maximum condensing within the boiler, the temperature of the water returning to the boiler from the system, needs to be a minimum of 54 degrees.
DELTA T
This means temperature difference, and generally when we're talking about boilers we are referring to the temperature difference between the flow and return. Flow is the water leaving the boiler and return is the water coming back to the boiler. Water within the pipes is heated up to a temperature by the boiler, it's then sent around the system where it sacrafices some of its heat (to the rads) and then returns to the boiler at a lower temperature. A system with a condensing boiler is designed with a delta T of 20 degrees and a non condensing boiler was designed to a delta T of 11 degrees.
RANGE RATING
Boilers come in different Kw outputs. When you range rate an appliance you are telling the boiler that it only needs to supply a certain amount of Kw. For example, if you have had a up to date heat loss calculation carried out and the maximum heating load for your rads is 8kw, you can tell the boiler this. So that if you had a 24kw boiler, it's not trying to send 24kw worth of energy to a 8Kw heating circuit. Depending on the boiler manufacture, this sometimes cannot be done and ironically where it can be done, it has not been - which adds to the inefficiency.
A really common example of this is where you install a high Kw Combi boiler to achieve the hot water demand needed. In Combi's, the hot water needs the high Kw output where as the heating generally doesn't. If we range rate, we can set a Kw output for hot water and then a different Kw for heating.
SYSTEM CLEANING / POWERFLUSH
A dirty system will contribute to the majority of breakdowns. A system should be thoroughly cleaned when installed and/or when a new appliance is installed onto it. Magnetite forms with corrosion and builds up within the system and can effect the operation of components, block radiators, pipework and even heat exchangers. It's a chemical reaction between the water and the different metals within the system. Inhibitors slow down the corrosion, a filter will catch some of the bi products of corrosion via a magnet - but both these methods will not fully stop corrosion.
MWT - MEAN WATER TEMPERATURE
This is the average temperature within the radiator. We add the flow temperature to the return temperature and then divide by 2. So if we have a 80 degree flow and 60 degree return, our MWT for the radiator is 70 degrees. This will then be used in conjunction with the design temperature and your heat loss calculations to pick your radiators.