- Joined
- 27 Jan 2008
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The idea of only heating the house or rooms within the house when required seems good, but the problem is speed to heat a room.
In one house we have a Myson radiator about 25 years old but still going strong, and with the fan car type radiator room heating is fast, also room cooling when it turns off, with the old off/on boiler once the thermostat turned off boiler one soon felt a chill before it cuts in again so we also fitted a standard radiator in the room which bridges the gap between off and on as it hold water so cools slower.
The radiator in the Myson holds very little water, so heats and cools fast, and there is no TRV as the fan controls output and has it's own thermostat, newer versions have multi speed fans so in a way modulate the output.
However modern boilers modulate with the temperature of the return water, so if the room with a Myson is warm enough even if every other room is still cold, it could turn the boiler down as there is no water restriction through the radiator. One odd one in kitchen in the kick space OK, but then it becomes an all or nothing, or work out a method to restrict (not turn off completely or it would never switch on again) the water through the Myson once the fan turns off.
However I have noted two fans to fit to normal radiators, one fits on top, radfan I thing it's called and one fits underneath the radiator booster fan I think it's called, in both cases circulating the hot air so have the potential to heat the room quicker and even like the Myson but still have a radiator with a TRV and will store some heat.
The one on the top seems to have two computer type fans and a thermostat built in so it only runs when radiator is hot, the one at bottom I have not worked out how it is controlled.
So I did an experiment, I have an upright fan which I placed at the side of the radiator, and I have a thermostat built for brewing beer and I taped the sensor on the return pipe so fan will only switch on when the radiator is hot.
It was a failure, once on it quickly cooled the radiator so return water quickly became cold and fan turned off, clearly the fan was far too big, but also it showed how the lock shield valve needs to be opened more once the fan starts, as the 15°C temperature drop across each radiator is set with all TRV's wide open and central heating running flat out, if one uses a fan then there would need to be two lock shield valves with second one on a solenoid so once fan starts you get extra flow.
However I am sure a very small fan would work as the radiator stands, but if very small, is it worth having in the first place.
So general idea is living room radiator would have fan, and the living room eTRV head would be set for geofencing so when we get near to home the living room temperature will raise faster than rest of house so it is warm when we get back, then rest of house can catch up latter. I tried geofencing since it's built into the electronic TRV head and it was a failure, too reasons, one the anti-hysteresis software in the head slows down rate of temperature increase for last two degrees C so it does not over shoot, and two is getting the boiler to fire up when the valve opens. The former can be go around by setting the valve two degrees higher than required, the second not so sure, but possible a relay to turn on boiler. Considering a MIHO014 from MiHome Energenie as same make as TRV heads so would use same hub.
But to stand a chance of working, reheat speed needs to increase at least for one room, once the room is up to new temperature I would want the fan to turn off, that could be a simple timer, although not sure how one would control the fan?
The 4YourHome Radiator Booster Fan seems rather lacking in info, seems to be extra low voltage
and it has a three position switch centre off and two speeds, 12 watt some pictures show it under the radiator others on top, this shows it under the radiator however all the so called technical data fails to say how it is switched on, I can see two switches may be one the same one?
The first I found was very simple
It also has both top and bottom versions in this case just one watt fan, but three major questions, one do they work, if so how well, and last how are they controlled so once room is warm they switch off?
In one house we have a Myson radiator about 25 years old but still going strong, and with the fan car type radiator room heating is fast, also room cooling when it turns off, with the old off/on boiler once the thermostat turned off boiler one soon felt a chill before it cuts in again so we also fitted a standard radiator in the room which bridges the gap between off and on as it hold water so cools slower.
The radiator in the Myson holds very little water, so heats and cools fast, and there is no TRV as the fan controls output and has it's own thermostat, newer versions have multi speed fans so in a way modulate the output.
However modern boilers modulate with the temperature of the return water, so if the room with a Myson is warm enough even if every other room is still cold, it could turn the boiler down as there is no water restriction through the radiator. One odd one in kitchen in the kick space OK, but then it becomes an all or nothing, or work out a method to restrict (not turn off completely or it would never switch on again) the water through the Myson once the fan turns off.
However I have noted two fans to fit to normal radiators, one fits on top, radfan I thing it's called and one fits underneath the radiator booster fan I think it's called, in both cases circulating the hot air so have the potential to heat the room quicker and even like the Myson but still have a radiator with a TRV and will store some heat.
The one on the top seems to have two computer type fans and a thermostat built in so it only runs when radiator is hot, the one at bottom I have not worked out how it is controlled.
So I did an experiment, I have an upright fan which I placed at the side of the radiator, and I have a thermostat built for brewing beer and I taped the sensor on the return pipe so fan will only switch on when the radiator is hot.
It was a failure, once on it quickly cooled the radiator so return water quickly became cold and fan turned off, clearly the fan was far too big, but also it showed how the lock shield valve needs to be opened more once the fan starts, as the 15°C temperature drop across each radiator is set with all TRV's wide open and central heating running flat out, if one uses a fan then there would need to be two lock shield valves with second one on a solenoid so once fan starts you get extra flow.
However I am sure a very small fan would work as the radiator stands, but if very small, is it worth having in the first place.
So general idea is living room radiator would have fan, and the living room eTRV head would be set for geofencing so when we get near to home the living room temperature will raise faster than rest of house so it is warm when we get back, then rest of house can catch up latter. I tried geofencing since it's built into the electronic TRV head and it was a failure, too reasons, one the anti-hysteresis software in the head slows down rate of temperature increase for last two degrees C so it does not over shoot, and two is getting the boiler to fire up when the valve opens. The former can be go around by setting the valve two degrees higher than required, the second not so sure, but possible a relay to turn on boiler. Considering a MIHO014 from MiHome Energenie as same make as TRV heads so would use same hub.
But to stand a chance of working, reheat speed needs to increase at least for one room, once the room is up to new temperature I would want the fan to turn off, that could be a simple timer, although not sure how one would control the fan?
The 4YourHome Radiator Booster Fan seems rather lacking in info, seems to be extra low voltage