More information has been added to the central heating control and thermostatic radiator valve pages in the heating section. This page is aimed at those who have either oil or gas central heating but some of the points will be applicable to any central heating system that uses electricity. A simple electricity saving technique is to switch off the central heating completely at the mains during the summer months if it is not required, saving at the very least the cost of running a time switch, sensors and motorized zone control valves. The power used by the central heating system controller is likely to be between 1 and 5 Watts. For more information on oil or gas central heating look at setting up and balancing central heating and the associated pages on radiators. It is vital that any temperature sensors in a central heating system are not in a draught as the sensor will not work properly and is likely to significantly increase heating costs.
More faults have been added to the thermostatic radiator valve and radiator fault finding pages in the heating section. There are many reasons why one or more radiators in a house are too cold or too hot, use the information on this page to identify the areas for investigation .Please read through all the possible diagnosis before jumping to conclusions. Always check the simple reasons first before looking for expert assistance, often the cause is simply due to thermostatic radiator valves (TRVs) being turned off or incorrectly set.
The information here makes the fundamental assumption that the system did work properly at some stage, if not then you are into investigating the design which is beyond the scope of this page. Whenever radiators are not working properly the heating system is not running at maximum efficiency which means there are opportunities to cut heating costs. If the rooms are reaching the desired temperature and the thermostatic valves are cutting off the flow it is likely that all the radiators will be at different temperatures. It all depends on how hard the radiator is working to maintain the temperature. The hotter the temperature the less the thermostatic valve is closing. How hard a radiator works depends on the size of room being heated, the size of the radiator, how high the thermostatic valve is set, how well insulated the room is and how often any external doors are opened and closed.
Generally downstairs radiators will be cooler as the rooms are insulated by any heated rooms above. If there is a very large difference and no other factors that affect this it may be worth looking at whether the loft insulation can be improved to reduce heat loss through the ceilings and cavity wall insulation to reduce heat loss through the walls. It is worth noting that radiators are likely to be slightly hotter at the top than the bottom, how much will vary from system to system, room to room, the design of the radiator and the airflow around it. As long as the difference is no worse than the drop across the radiator this is not an indication of a problem. Before jumping to the conclusion there is a fault make sure the system has fully stabilised first.
Winter is cioming and now is the time to make sure the central heating is working properly. Setting up and balancing the central heating system has been updated with new information.
Before embarking on what can be a time consuming process it is worth finding out whether the system needs balancing. With the system at normal working temperature and all thermostatically controlled valves on the radiators fully open (remembering to record their original positions) measure the temperature difference across each radiator. If this difference is significantly different from 12 degrees Centigrade (20 degrees Fahrenheit) for any radiator then adjustment is required. If all radiators have a similar drop that is not 12 degrees Centigrade (20 degrees Fahrenheit) it may only be necessary to adjust the pump speed and/or boiler temperature – see step 17 below onwards. If any radiators are significantly cooler at the top compared to the bottom then try bleeding the radiator before measuring the temperature drop. It is a waste of time trying to do this on a hot summers day as the system will probably not need to work at all and some strange results will occur. If any radiators are not working at all and they used to work try bleeding the radiator. Don’t forget that towel rails in bathrooms heated by the system need to be dealt with just like radiators. If these tips don’t solve the problem the radiator faults page will help with suggestions.