System Balancing

Central heating systems today are fitted with a choice of two circulating pumps that feed the systems. Firstly there is the Fix Headed Pump that will always run at a constant speed, and so pumps the hot water around the heating system at a constant rate of flow. The second pump is slightly different with the speed of Variable Headed Pump being adjustable. On installing a variable headed pump the installer will balance the radiators, and adjust the pump speed in order to find the most effective temperature for all rooms that are fitted with radiators. A London Boiler Installation operative can fit all central heating system pumps. Sometimes, a room’s temperature cannot be changed by opening a radiator’s valve, but it can be adjusted by varying the speed at which the circulating pump is runs. However, before adjusting this pump, you should make sure that all the radiators are showing the same temperature drop. There are clip on thermometers specific to the job that can be bought to measure this. Clip one of the thermometers to the feed pipe just below the radiator valve and the other one to the return pipe, also below the valve. There really should be a temperature differential of around 11°C (or 20°F). If this is not the case then, close the lockshield valve on the radiator slightly to increase the difference in temperature or open the valve to lower it. If the radiator temperature differences are approaching nearly the correct values, and before any final fine adjustments, the temperature drop across the index radiator should be considered (this is the one that has a much higher drop across it than the rest). If this is really different from the 11 deg. C figure then the pump should be adjusted. If the temperature drop is greater than the design figure the pump needs to be increased in speed, and the converse for too little a temperature drop. If it is not possible to decrease the pump speed any lower, its isolating valves can be used to further restrict the flow. Any doubts don’t hesitate to contact a professional plumbers like London Boiler Installations who have the relevant skills to carry out all plumbing work and provide peace of mind guarantees for all jobs.
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