Thermostat cost
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Basic unit costs around £6.50, the programmable head around £10 these prices can go up to around a £100 for the pair if you really want to pay that much.
Changing the valves there are a few methods, clearly you want to stop the water damaging the floor, so you could drain down which means new inhibitor or freezer the pipes or work fast and suck up what comes out, if inhibitor added water tends to be clear, but if not it can contain a lot of rust.
I am not a plumber, the last one I wanted to fit was on ground floor carpeted on quarry tiles, I got everything ready, including a Vax carpet cleaner, working fast with lock shield turned off the water radiated about 6 inches from valve and was quickly sucked up by carpet cleaner, but I would not use that method upstairs where getting it wrong could end up with water coming through the ceiling.
As to advantages I really don't know why anyone would not fit them, specially on upper floors, I find heat raises, and how much it raises depends on if doors open or closed, it does not matter how many times my mother said cau'r drws or put wood in hole, I would leave doors open, so the amount of heat going up stairs varies, so it is impossible by adjusting the lock shield valve to set temperatures in each room, also wind direction and sun through windows will alter what proportion of energy is required for each room, so the TRV stops the upper rooms overheating.
It in essence makes every room its own zone, however although it can stop over heating, it can't without an electronic head tell the boiler to run, neither can it totally stop the boiler running, so there must be some where for the water to go, so the by-pass valve is an integral part of TRV control, and some how there still needs to be a method to tell the boiler when no longer required.
Traditionally the hall radiator would not have a TRV, does not really make sense, other option was bathroom towel rail with no TRV, so always a path for water to circulate, the by-pass valve removed this requirement to some extent. So modern boiler heats water to say 70°C and pumps it round the system and turns down the flame height (modulates) so return water is around 40°C until it can't turn it down any more, when it starts to cycle off/on to further reduce output, however it will not totally switch off, so some where you need a thermostat to turn off the boiler in the summer, or of course do it manually.
So a TRV set to 18°C in hall and a wall thermostat set to 19°C in the hall the wall thermostat will not operate in winter but will work in the summer stopping the boiler from cycling, well in theory, in practice because the wall thermostat is higher the actual difference may need to be higher, and it means altering temperature day, evening, and over night becomes impossible, it can be done with programmable TRV head and wall thermostat, but it takes a lot of fiddling to get it to work A1.
So the easy way is for the wall thermostat to become a hub receiving info from the wifi TRV heads to form an integrated system.
However there is no perfect system, it is always a compromise.
Changing the valves there are a few methods, clearly you want to stop the water damaging the floor, so you could drain down which means new inhibitor or freezer the pipes or work fast and suck up what comes out, if inhibitor added water tends to be clear, but if not it can contain a lot of rust.
I am not a plumber, the last one I wanted to fit was on ground floor carpeted on quarry tiles, I got everything ready, including a Vax carpet cleaner, working fast with lock shield turned off the water radiated about 6 inches from valve and was quickly sucked up by carpet cleaner, but I would not use that method upstairs where getting it wrong could end up with water coming through the ceiling.
As to advantages I really don't know why anyone would not fit them, specially on upper floors, I find heat raises, and how much it raises depends on if doors open or closed, it does not matter how many times my mother said cau'r drws or put wood in hole, I would leave doors open, so the amount of heat going up stairs varies, so it is impossible by adjusting the lock shield valve to set temperatures in each room, also wind direction and sun through windows will alter what proportion of energy is required for each room, so the TRV stops the upper rooms overheating.
It in essence makes every room its own zone, however although it can stop over heating, it can't without an electronic head tell the boiler to run, neither can it totally stop the boiler running, so there must be some where for the water to go, so the by-pass valve is an integral part of TRV control, and some how there still needs to be a method to tell the boiler when no longer required.
Traditionally the hall radiator would not have a TRV, does not really make sense, other option was bathroom towel rail with no TRV, so always a path for water to circulate, the by-pass valve removed this requirement to some extent. So modern boiler heats water to say 70°C and pumps it round the system and turns down the flame height (modulates) so return water is around 40°C until it can't turn it down any more, when it starts to cycle off/on to further reduce output, however it will not totally switch off, so some where you need a thermostat to turn off the boiler in the summer, or of course do it manually.
So a TRV set to 18°C in hall and a wall thermostat set to 19°C in the hall the wall thermostat will not operate in winter but will work in the summer stopping the boiler from cycling, well in theory, in practice because the wall thermostat is higher the actual difference may need to be higher, and it means altering temperature day, evening, and over night becomes impossible, it can be done with programmable TRV head and wall thermostat, but it takes a lot of fiddling to get it to work A1.
So the easy way is for the wall thermostat to become a hub receiving info from the wifi TRV heads to form an integrated system.
However there is no perfect system, it is always a compromise.
Blah blah blah.. It's a pig to fit trvs onto microbore as the copper is soft and invariably leaks. Best thing is to cut back the pipe and use long-tail 8/10 to 15mm endfeed reducers straight into standard 15mm valves. But this depends on you getting all the water out the pipes. Normally it's best to leave well alone.
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£360
You can get 10mm native TRV's which will fit your pipework. You may have to remove the old olives and nuts though as the old nuts & threads are invariably different.
Price would really be based on location and system type & materials (inhibitor, type/quality of TRV's, etc) unfortunately nigh impossible to give an estimate on a forum like this, if that's what you are looking for.
Price would really be based on location and system type & materials (inhibitor, type/quality of TRV's, etc) unfortunately nigh impossible to give an estimate on a forum like this, if that's what you are looking for.
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