Radiator Problem
- Thread starter oldgarden
- Start date
Quite possibly no problem at all. Modern boilers are set to deliver heating water at relatively low temperature (for best fuel efficiency). If you're used to an older system the radiators will feel cooler in general
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Hot water raises so when the TRV opens it will naturally go to top, but as it closes due to room being warm enough there is no flow to push water to bottom.
Radiators need setting there are two controls, the TRV which turns radiator up/down as required and the lock shield valve which adjusts the speed that the radiator heats up at, the TRV takes time to open and close, and so there needs to be time for it to work.
This should be set up when installed, the water in is set a amount in degrees C higher that water out, often around 12°C, this also ensures every room gets its fair share of heat.
Radiators need setting there are two controls, the TRV which turns radiator up/down as required and the lock shield valve which adjusts the speed that the radiator heats up at, the TRV takes time to open and close, and so there needs to be time for it to work.
This should be set up when installed, the water in is set a amount in degrees C higher that water out, often around 12°C, this also ensures every room gets its fair share of heat.
Thanks for explaining that. Didnt quite follow all of it but I think you are saying the lock sheild on the rads could need adjusting. Hoping its that rather than some obstructino some where. Certainly I dont think there was much attention to setting the rads up; they were put on at different times and also taken off for plastering etc.
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Please remember I am an electrician, not a heating guy.
I did not consider central heating in first two houses, it worked, so no reason to look at it, first was gas hot air, second was open plan house. Then I returned to parents old house to look after my mother, and the central heating was a nightmare. Main problem was the bay windows which resulted in room temperatures changing depending on if the sun came out, so I looked into how central heating works.
It seems everything changed with the condensing boiler, the whole idea of the condensing boiler is to gain the latent heat from the flue gases, and to do this the boiler needs to modulate (turn down) to ensure the return water is cool enough, so ideal is when as the house warms up the boiler slowly turns down until it can't turn down any more, at which point it starts to cycle off/on (called mark/space ratio) and it turns back on at low output. If a on/off thermostat is added then when it turns boiler back on, it turns it on at full output, so the wall on/off thermostat is really only to turn boiler off when summer arrives to stop it cycling, there are modulating thermostats which also tell the boiler what output is required, these can be fitted in the main room, but the on/off thermostat is fitted in a room normally kept cool say under 18°C so it will stop boiler firing up on what promises to be a warm day.
So main control is with the TRV's, and the four electronic TRV's I fitted to mothers house gave me both target and current temperature.
as a result setting the lock shield was made easier, if after heating had been running for some time target under current open the lock shield a little, and if over close it a little, and once set all rooms on a dull day worked A1, the bay windows still caused a problem when sun came out, but that was reduced from 32°C to 24°C when set at 20°C. The reason was two fold, the TRV worked faster, and the water was cooler to start with so radiator cooled faster. On leaving the house after mother death, we replaced the electronic with the old manual, and found not lock shield set, these worked nearly as well.
But setting the lock shield not easy, my first attempt starting closest to boiler, was close each lock shield and allow radiator to cool, well at least pipes, then open ¼ turn at a time, until pipe got warm, then move to next radiator, this did mean all radiators worked, no one radiator was starving the others. However the hall radiator where the wall thermostat was, proved a problem.
When front door opened hall went cold, as expected, and to set the lock shield to get radiator hot enough to reheat hall, resulted in once reheated it turned off the boiler so rest of house cool, closing the lock shield in the hall rest of house warm, but hall never heated up. I was told not to fit a TRV to hall radiator, but I did, and that transformed the heating, now when door opened hall cooled and TRV turned on, so reheated hall fast, but before it reached the 19°C set on the wall thermostat the TRV had started to close, set at 17.5°C it would in fullness of time switch off the wall thermostat but only on warm days, or when a scheduled change was programmed, i.e. over night, however to have a programmable wall thermostat you also need a programmable TRV so they match each other.
New house different problem as yet not cured, now use oil central heating, and hall cools down too slow, and not a modulating boiler.
But with a modulating boiler the main thing is each room is controlled by the TRV and lock shield valve, not the wall thermostat, unless the wall thermostat is a modulating type or linked to the TRV's. Not all boilers can use a modulating thermostat, and some that can are limited to types which will not connect to the TRV heads. But with set up in mothers house the TRV did not need to connect to wall thermostat, just needed the same schedule. So I got in this house the 4 original Energenie TRV heads from mothers house, and 5 eQ-3 heads far cheaper only paid £15 each.
This cheap TRV
only shows target, so harder to set lock shield valve, I tried setting them with this 
thermometer, it did have a setting for babies bottles etc, so theory should have worked, but in practice I could not get a steady reading, the plumbers use some thing like this 
which I assume does work, and it should have been set up for you. However to date I have not seen any plumber/heating guy use one, maybe they did and I missed it, but my parents house every lock shield valve was wide open, central heating part paid for with government grant, but the installer actually failed to change the power shower which was illegal to use once the cold and hot water was direct from main with no header tank, so clearly a cowboy firm.
I did not consider central heating in first two houses, it worked, so no reason to look at it, first was gas hot air, second was open plan house. Then I returned to parents old house to look after my mother, and the central heating was a nightmare. Main problem was the bay windows which resulted in room temperatures changing depending on if the sun came out, so I looked into how central heating works.
It seems everything changed with the condensing boiler, the whole idea of the condensing boiler is to gain the latent heat from the flue gases, and to do this the boiler needs to modulate (turn down) to ensure the return water is cool enough, so ideal is when as the house warms up the boiler slowly turns down until it can't turn down any more, at which point it starts to cycle off/on (called mark/space ratio) and it turns back on at low output. If a on/off thermostat is added then when it turns boiler back on, it turns it on at full output, so the wall on/off thermostat is really only to turn boiler off when summer arrives to stop it cycling, there are modulating thermostats which also tell the boiler what output is required, these can be fitted in the main room, but the on/off thermostat is fitted in a room normally kept cool say under 18°C so it will stop boiler firing up on what promises to be a warm day.
So main control is with the TRV's, and the four electronic TRV's I fitted to mothers house gave me both target and current temperature.
as a result setting the lock shield was made easier, if after heating had been running for some time target under current open the lock shield a little, and if over close it a little, and once set all rooms on a dull day worked A1, the bay windows still caused a problem when sun came out, but that was reduced from 32°C to 24°C when set at 20°C. The reason was two fold, the TRV worked faster, and the water was cooler to start with so radiator cooled faster. On leaving the house after mother death, we replaced the electronic with the old manual, and found not lock shield set, these worked nearly as well.But setting the lock shield not easy, my first attempt starting closest to boiler, was close each lock shield and allow radiator to cool, well at least pipes, then open ¼ turn at a time, until pipe got warm, then move to next radiator, this did mean all radiators worked, no one radiator was starving the others. However the hall radiator where the wall thermostat was, proved a problem.
When front door opened hall went cold, as expected, and to set the lock shield to get radiator hot enough to reheat hall, resulted in once reheated it turned off the boiler so rest of house cool, closing the lock shield in the hall rest of house warm, but hall never heated up. I was told not to fit a TRV to hall radiator, but I did, and that transformed the heating, now when door opened hall cooled and TRV turned on, so reheated hall fast, but before it reached the 19°C set on the wall thermostat the TRV had started to close, set at 17.5°C it would in fullness of time switch off the wall thermostat but only on warm days, or when a scheduled change was programmed, i.e. over night, however to have a programmable wall thermostat you also need a programmable TRV so they match each other.
New house different problem as yet not cured, now use oil central heating, and hall cools down too slow, and not a modulating boiler.
But with a modulating boiler the main thing is each room is controlled by the TRV and lock shield valve, not the wall thermostat, unless the wall thermostat is a modulating type or linked to the TRV's. Not all boilers can use a modulating thermostat, and some that can are limited to types which will not connect to the TRV heads. But with set up in mothers house the TRV did not need to connect to wall thermostat, just needed the same schedule. So I got in this house the 4 original Energenie TRV heads from mothers house, and 5 eQ-3 heads far cheaper only paid £15 each.
This cheap TRV
only shows target, so harder to set lock shield valve, I tried setting them with this thermometer, it did have a setting for babies bottles etc, so theory should have worked, but in practice I could not get a steady reading, the plumbers use some thing like this which I assume does work, and it should have been set up for you. However to date I have not seen any plumber/heating guy use one, maybe they did and I missed it, but my parents house every lock shield valve was wide open, central heating part paid for with government grant, but the installer actually failed to change the power shower which was illegal to use once the cold and hot water was direct from main with no header tank, so clearly a cowboy firm.
Certainly sounds like the system needs balanced, basically your rads are getting rid of the heat entering the rad before enough hot water can circulate properly to heat the whole radiator therefore the radiators aren't working at proper efficiency. The delta T - the temperature difference between the water in to the water out - should have been set when the system was installed and comissioned.
Get the installer back in, they should have set the system up properly.
Get the installer back in, they should have set the system up properly.
Agree I think your system needs balancing
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One pipe system ???
if al new pipework, I would be surprised if it was a one pipe system, who knows though , only the installer, get them back and tell them to balance it
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