I asked a question here on replacing my boiler and got a great responce! THANK YOU!My question now on my system which is a baxi (i think) back boiler, on the front fire there is a pull off panel to which reveals the thermostat, this goes from low,1,2,3,4,high, all my radiators have control dials to which i can control temperature, does this back boiler thermostat just control the water temperature or does this affect the radiators also? also on the other end of my radiator is just a cap with a + and - symbol , a user Robert J has gave me advise to not have these fully open which THEY WERE! so i will sort this tonight! thanks guys
That thermostat probably sets the internal water temperature in the boiler. It most likely controls both the hot water temperature and the temperature of water circulated through the radiators. Try the manual valves on the radiators at about half a turn open to start with. Turn the thermostatic valves to maximum while setting up so they do not confuse the test. All the radiators should get warm at a roughly equal speed when set right, so if one gets hot noticeably faster close the valve on that a fraction and open it a touch on the slowest until they are something like even. Once all the radiators are hot, set the radiator thermostatic valves to the appropriate temperature. Quite a few are marked 1 to 5 with 3 being around 21'C and roughly 3'C per number. Once a room gets to it's set heat and the radiator flow settles, you should find that the top centre of the radiator is noticeably warmer than the bottom at the middle. Without thermostats on the hot water tank and in a room, the boiler will be running or staying hot all the time the heating or hot water is enabled, and the pump running for heating, which costs money. If you have a friendly electrician, the wiring for room and tank thermostats is quite simple. The link below has info on this the first link 'Gravity hot water wiring diagram' has the electrical info. My setup is based on that, but with a modern 7 day programmer rather than the simple time switch. If you do that, it needs to be a programmer than has the option for 'Gravity hot water' - not all do. The heating output feeds the room thermostat and the hot water output feeds the cylinder 'stat. The parts cost should be under ?100 and you will see immediate savings on your gas bill.
A gravity hot water circuit cannot be controlled with a thermostat alone.A motorised valve would need to be fitted to stop the circulation to the tank when there is still demand for heating.A mechanical pipe stat could be fitted but they are a lot less reliable. The thermostat on the boiler controls the overall temperature of the water that runs through the radiators and to the coil in the hot water tank.The radiator thermostats control the room temperature. If the radiators heat fully,top to bottom then leave the lock shields alone.They are used to balance the system to ensure each radiator gets its fair share of the hot water.If the water returning to the boiler is still hot then the boiler will use less energy to re heat it.Ideally there should be a 11 degree difference between the flow from the boiler to the return back to the boiler.
