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Room thermostat wiring conundrum
Well it's a coundrum to me.
This is a photograph of the wiring of the existing Drayton thermostat: https://1drv.ms/u/s!AkhvgPvXD0_1jdp0...rU-7w?e=4lk9Id I'd like to replace it with a Myson device, which is wired thus: https://1drv.ms/u/s!AkhvgPvXD0_1jdp2...r-T9A?e=5zLx3L (Another picture) So what wire goes where? My first attempt to install it blew the fuse in the switch. Thanks. |
Room thermostat wiring conundrum
On Sunday, 17 January 2021 at 14:26:28 UTC, Peter Johnson wrote:
Well it's a coundrum to me. This is a photograph of the wiring of the existing Drayton thermostat: https://1drv.ms/u/s!AkhvgPvXD0_1jdp0...rU-7w?e=4lk9Id I'd like to replace it with a Myson device, which is wired thus: https://1drv.ms/u/s!AkhvgPvXD0_1jdp2...r-T9A?e=5zLx3L (Another picture) So what wire goes where? My first attempt to install it blew the fuse in the switch. Thanks. The MRTE is a two wire device using batteries to power the electronics. I had a similar situation changing a previous 3 wire device to the MRTE last week. Connect the red wire (L) to C (terminal 2) in the MRTE and the yellow which will be the switched live to NO (terminal 1). You do not need the Neutral (blue wire) and will have to terminate it off either as I did with a Wago connector or a single terminal off a terminal strip. Richard |
Room thermostat wiring conundrum
Peter Johnson Wrote in message:
Well it's a coundrum to me. This is a photograph of the wiring of the existing Drayton thermostat: https://1drv.ms/u/s!AkhvgPvXD0_1jdp0...rU-7w?e=4lk9Id I'd like to replace it with a Myson device, which is wired thus: https://1drv.ms/u/s!AkhvgPvXD0_1jdp2...r-T9A?e=5zLx3L (Another picture) So what wire goes where? My first attempt to install it blew the fuse in the switch. Thanks. Red to "C" Yellow to "N.O." Insulate and do not connect the blue neutral. -- %Profound_observation% ----Android NewsGroup Reader---- http://usenet.sinaapp.com/ |
Room thermostat wiring conundrum
On Sun, 17 Jan 2021 14:26:25 +0000, Peter Johnson wrote:
Well it's a coundrum to me. This is a photograph of the wiring of the existing Drayton thermostat: https://1drv.ms/u/s!AkhvgPvXD0_1jdp0...rU-7w?e=4lk9Id I'd like to replace it with a Myson device, which is wired thus: https://1drv.ms/u/s!AkhvgPvXD0_1jdp2...r-T9A?e=5zLx3L (Another picture) So what wire goes where? My first attempt to install it blew the fuse in the switch. Thanks. Assuming the original thermostat is wired correctly: Red is permanent live which will go to "C". Yellow is switched live which will go to either NO or NC (I think NO, but it depends which position the thermostat considers "normal" - the wrong one will turn the heating on when it's hot and off when it's cold, so just swap it over). Blue is neutral, which the new thermostat doesn't need (presumably it's battery powered?), so put a choc-block terminal on it. There should be an earth wire too, though I don't see it - but the new thermostat looks to be all plastic so doesn't need this either. Put a choc-block on this too. Mike |
Room thermostat wiring conundrum
On 17/01/2021 14:40, Graham. wrote:
Peter Johnson Wrote in message: Well it's a coundrum to me. This is a photograph of the wiring of the existing Drayton thermostat: https://1drv.ms/u/s!AkhvgPvXD0_1jdp0...rU-7w?e=4lk9Id I'd like to replace it with a Myson device, which is wired thus: https://1drv.ms/u/s!AkhvgPvXD0_1jdp2...r-T9A?e=5zLx3L (Another picture) So what wire goes where? My first attempt to install it blew the fuse in the switch. Thanks. Red to "C" Yellow to "N.O." Insulate and do not connect the blue neutral. +1 Red (live) to C (common) Yellow (switched live) to NO (Normally Open) Blue not used so should be made safe and not connected to anything. The NC (Normally closed) terminal is also unused. -- mailto : news {at} admac {dot} myzen {dot} co {dot} uk |
Room thermostat wiring conundrum
On 17/01/2021 14:26, Peter Johnson wrote:
Well it's a coundrum to me. This is a photograph of the wiring of the existing Drayton thermostat: https://1drv.ms/u/s!AkhvgPvXD0_1jdp0...rU-7w?e=4lk9Id I'd like to replace it with a Myson device, which is wired thus: https://1drv.ms/u/s!AkhvgPvXD0_1jdp2...r-T9A?e=5zLx3L (Another picture) So what wire goes where? My first attempt to install it blew the fuse in the switch. Thanks. Everyone has answered this. So I'll just add make sure it was a 3A fuse that you fitted into the fused spur -- Adam |
Room thermostat wiring conundrum
On 17/01/2021 14:40, Tricky Dicky wrote:
On Sunday, 17 January 2021 at 14:26:28 UTC, Peter Johnson wrote: Well it's a coundrum to me. This is a photograph of the wiring of the existing Drayton thermostat: https://1drv.ms/u/s!AkhvgPvXD0_1jdp0...rU-7w?e=4lk9Id I'd like to replace it with a Myson device, which is wired thus: https://1drv.ms/u/s!AkhvgPvXD0_1jdp2...r-T9A?e=5zLx3L (Another picture) So what wire goes where? My first attempt to install it blew the fuse in the switch. Thanks. The MRTE is a two wire device using batteries to power the electronics. I had a similar situation changing a previous 3 wire device to the MRTE last week. Connect the red wire (L) to C (terminal 2) in the MRTE and the yellow which will be the switched live to NO (terminal 1). You do not need the Neutral (blue wire) and will have to terminate it off either as I did with a Wago connector or a single terminal off a terminal strip. Richard For "do not need" read "*must* not connect". The blue (neutral) wire would originally have been used in a mechanical stat as the return from the accelerator heater (which reduced hysteresis). No longer used in modern digital stats. If you connect it to *anything*, it will blow the fuse under one condition or another. -- Cheers, Roger |
Room thermostat wiring conundrum
On 17/01/2021 14:40, Graham. wrote:
Peter Johnson Wrote in message: Well it's a coundrum to me. This is a photograph of the wiring of the existing Drayton thermostat: https://1drv.ms/u/s!AkhvgPvXD0_1jdp0...rU-7w?e=4lk9Id I'd like to replace it with a Myson device, which is wired thus: https://1drv.ms/u/s!AkhvgPvXD0_1jdp2...r-T9A?e=5zLx3L (Another picture) So what wire goes where? My first attempt to install it blew the fuse in the switch. Thanks. Red to "C" Yellow to "N.O." Insulate and do not connect the blue neutral. It depends what 'normal' means - you might want yellow to NC.... -- Climate is what you expect but weather is what you get. Mark Twain |
Room thermostat wiring conundrum
Peter Johnson wrote in
: Well it's a coundrum to me. This is a photograph of the wiring of the existing Drayton thermostat: https://1drv.ms/u/s!AkhvgPvXD0_1jdp0...rU-7w?e=4lk9Id I'd like to replace it with a Myson device, which is wired thus: https://1drv.ms/u/s!AkhvgPvXD0_1jdp2...r-T9A?e=5zLx3L (Another picture) So what wire goes where? My first attempt to install it blew the fuse in the switch. Thanks. Connecting the neutral and blowing the fuse may have killed the new therrmostat. |
Room thermostat wiring conundrum
On 18/01/2021 06:54, The Natural Philosopher wrote:
On 17/01/2021 14:40, Graham. wrote: Peter Johnson Wrote in message: Well it's a coundrum to me. This is a photograph of the wiring of the existing Drayton thermostat: https://1drv.ms/u/s!AkhvgPvXD0_1jdp0...rU-7w?e=4lk9Id I'd like to replace it with a Myson device, which is wired thus: https://1drv.ms/u/s!AkhvgPvXD0_1jdp2...r-T9A?e=5zLx3L (Another picture) So what wire goes where? My first attempt to install it blew the fuse in the switch. Thanks. Red to "C" Yellow to "N.O." Insulate and do not connect the blue neutral. It depends what 'normal' means - you might want yellow to NC.... There are only 3 connections in the original back box which corresponds to the wiring for a Drayton RTS1, RTS2 or RTS3 device where the yellow wire is in the position for switched live from a normally open (NO) switch contact. -- mailto : news {at} admac {dot} myzen {dot} co {dot} uk |
Room thermostat wiring conundrum
On 18/01/2021 08:59, JohnP wrote:
Peter Johnson wrote in : Well it's a coundrum to me. This is a photograph of the wiring of the existing Drayton thermostat: https://1drv.ms/u/s!AkhvgPvXD0_1jdp0...rU-7w?e=4lk9Id I'd like to replace it with a Myson device, which is wired thus: https://1drv.ms/u/s!AkhvgPvXD0_1jdp2...r-T9A?e=5zLx3L (Another picture) So what wire goes where? My first attempt to install it blew the fuse in the switch. Thanks. Connecting the neutral and blowing the fuse may have killed the new therrmostat. Possible but unlikely. The 3 contacts in the new thermostat will be three contacts to a relay inside the device and with no connections to any of the electronics within the device. With no provision for a mains neutral it indicates that the thermostat is battery operated and the output switching is isolated from the electronics. There is a possibility with a direct short between mains live and neutral that relay contacts may have welded themselves together or there has been some arcing. The fuse probably popped fast enough to prevent any damage. -- mailto : news {at} admac {dot} myzen {dot} co {dot} uk |
Room thermostat wiring conundrum
On Monday, 18 January 2021 at 09:57:26 UTC, alan_m wrote:
On 18/01/2021 08:59, JohnP wrote: Peter Johnson wrote in : Well it's a coundrum to me. This is a photograph of the wiring of the existing Drayton thermostat: https://1drv.ms/u/s!AkhvgPvXD0_1jdp0...rU-7w?e=4lk9Id I'd like to replace it with a Myson device, which is wired thus: https://1drv.ms/u/s!AkhvgPvXD0_1jdp2...r-T9A?e=5zLx3L (Another picture) So what wire goes where? My first attempt to install it blew the fuse in the switch. Thanks. Connecting the neutral and blowing the fuse may have killed the new therrmostat. Possible but unlikely. The 3 contacts in the new thermostat will be three contacts to a relay inside the device and with no connections to any of the electronics within the device. With no provision for a mains neutral it indicates that the thermostat is battery operated and the output switching is isolated from the electronics. There is a possibility with a direct short between mains live and neutral that relay contacts may have welded themselves together or there has been some arcing. The fuse probably popped fast enough to prevent any damage. -- mailto : news {at} admac {dot} myzen {dot} co {dot} uk The enclosed installation notes show the same wiring diagram but go further by indicating which terminals are for heating and which for cooling. https://www.myson.co.uk/static_files...structions.pdf Richard |
Room thermostat wiring conundrum
On 18/01/2021 09:57, alan_m wrote:
There is a possibility with a direct short between mains live and neutral that relay contacts may have welded themselves together or there has been some arcing. The fuse probably popped fast enough to prevent any damage. This is exactly what happened to me when the boiler installer misfitted my new room thermostat. The spot weld on the controller relay froze in the off position. I called the boiler installer back and he seemed to get very stressed when I took an interested in what he was doing, eventually he left without fixing it. A bit of a shame really as he did a good job otherwise. I probably went into software developer mode, we mess so much up we are less ashamed about it, I hadn't expect him to be bothered. After he had gone I opened up the controller and flicked the welded relay apart. I then wired the thermostat up correctly. It's been working fine for 6 years. FWIW the old style thermostats needed three wires. When off they put a small current though a big resistor to warm the thermostat slightly. This created a hysteresis effect and stopped the thermostat switching on an off too quickly. The new thermostat is annoyingly noisy. |
Room thermostat wiring conundrum
Thanks everyone for your helpful comments and advice. New thermostat
now up and running. My uneducated attempt to install it did do some damage to the timer (a Drayton Tempus 7) when the fuse blew because when I reinstated the old thermostat the boiler responded to it regardless of the settings on the timer, so I got a click and collect Drayton LP822 from Wickes yesterday and the boiler came on as soon as I'd finished configuring it. The old one had a warranty expiry date of July 2003 so it's served me well. Thanks again. |
Room thermostat wiring conundrum
On 18/01/2021 11:03, Pancho wrote:
FWIW the old style thermostats needed three wires. When off they put a small current though a big resistor to warm the thermostat slightly. This created a hysteresis effect and stopped the thermostat switching on an off too quickly. Er no, it was to *reduce* the hysteresis... -- Future generations will wonder in bemused amazement that the early twenty-first centurys developed world went into hysterical panic over a globally average temperature increase of a few tenths of a degree, and, on the basis of gross exaggerations of highly uncertain computer projections combined into implausible chains of inference, proceeded to contemplate a rollback of the industrial age. Richard Lindzen |
Room thermostat wiring conundrum
On 18/01/2021 13:15, Peter Johnson wrote:
Thanks everyone for your helpful comments and advice. New thermostat now up and running. My uneducated attempt to install it did do some damage to the timer (a Drayton Tempus 7) Mine is a Drayton Tempus 6, it's time of servitude isn't over yet. I suspect you could have fixed it, but on the other hand you have a smart shiny new one and I have a dull one with a cracked plastic lid. If buying a new one I would have been tempted to look at a wifi/smart one. |
Room thermostat wiring conundrum
On 18/01/2021 13:16, The Natural Philosopher wrote:
On 18/01/2021 11:03, Pancho wrote: FWIW the old style thermostats needed three wires. When off they put a small current though a big resistor to warm the thermostat slightly. This created a hysteresis effect and stopped the thermostat switching on an off too quickly. Er no, it was to *reduce* the hysteresis... Er no, surely you want hysteresis otherwise you get vacillation, rapid switching on an off. |
Room thermostat wiring conundrum
In article ,
Brian Gaff \(Sofa\) wrote: It kind of makes you wonder why they do not provide a place for any vacant wire that goes nowhere for safety really. That would just confuse someone starting afresh. "What are all those spare terminals for?" -- *How does Moses make his tea? Hebrews it.* Dave Plowman London SW To e-mail, change noise into sound. |
Room thermostat wiring conundrum
In article ,
Pancho wrote: This is exactly what happened to me when the boiler installer misfitted my new room thermostat. Odd, isn't it? Now most boilers have electronic control, they are still fitted by a monkey with a 'gas safe' badge. -- *I don't know what your problem is, but I'll bet it's hard to pronounce Dave Plowman London SW To e-mail, change noise into sound. |
Room thermostat wiring conundrum
In article ,
Pancho wrote: On 18/01/2021 13:15, Peter Johnson wrote: Thanks everyone for your helpful comments and advice. New thermostat now up and running. My uneducated attempt to install it did do some damage to the timer (a Drayton Tempus 7) Mine is a Drayton Tempus 6, it's time of servitude isn't over yet. I suspect you could have fixed it, but on the other hand you have a smart shiny new one and I have a dull one with a cracked plastic lid. If buying a new one I would have been tempted to look at a wifi/smart one. Do you really need the ability to control your thermostat from a mobile phone, etc? Making it more expensive and less reliable? Purely to be in fashion? -- *Most people have more than the average number of legs* Dave Plowman London SW To e-mail, change noise into sound. |
Room thermostat wiring conundrum
On 18/01/2021 09:57, alan_m wrote:
With no provision for a mains neutral it indicates that the thermostat is battery operated Not necessarily - although it almost certainly is. The traditional bi-metallic stat didn't need electricity to drive it. The only reason for the neutral was to provide a return for the accelerator heater - but the stat would still work if you didn't connect it. -- Cheers, Roger |
Room thermostat wiring conundrum
On 18/01/2021 13:45, Pancho wrote:
On 18/01/2021 13:16, The Natural Philosopher wrote: On 18/01/2021 11:03, Pancho wrote: FWIW the old style thermostats needed three wires. When off they put a small current though a big resistor to warm the thermostat slightly. This created a hysteresis effect and stopped the thermostat switching on an off too quickly. Er no, it was to *reduce* the hysteresis... Er no, surely you want hysteresis otherwise you get vacillation, rapid switching on an off. There needs to be a *bit* of hysteresis to avoid rapid cycling - but mechanical stats have this naturally, with a margin between the on and off points. *However* if the room stat only switches the heating off when the set point is reached, the rads are still hot and the room temperature will go on rising. Not only does this waste heat, but the room then takes a long time to cool and the occupants start to feel cold before the heating comes on again. The accelerator heater fools the stat into thinking that the set point has been reached a bit before it is actually reached. This greatly reduces the overshoot. -- Cheers, Roger |
Room thermostat wiring conundrum
"Dave Plowman (News)" wrote in
: In article , Pancho wrote: This is exactly what happened to me when the boiler installer misfitted my new room thermostat. Odd, isn't it? Now most boilers have electronic control, they are still fitted by a monkey with a 'gas safe' badge. Yes - people call in a Plumber to fix a boiler! People expect an electrician to be able to fix a washing machine. What some tradesmen lack is an understanding of "Control Logic". Time Served Qualified Plumber - what does this mean - can bend and fit pipes? I recall at a place where I worked we employed "Instalation Electricians! and "Maintenance Electricians" Different aptitudes. |
Room thermostat wiring conundrum
On 18/01/2021 15:16, Roger Mills wrote:
There needs to be a *bit* of hysteresis to avoid rapid cycling - but mechanical stats have this naturally, with a margin between the on and off points. *However* if the room stat only switches the heating off when the set point is reached, the rads are still hot and the room temperature will go on rising. Not only does this waste heat, but the room then takes a long time to cool and the occupants start to feel cold before the heating comes on again. The accelerator heater fools the stat into thinking that the set point has been reached a bit before it is actually reached. This greatly reduces the overshoot. You sound convincing. I would need to think long and hard to get it straight in my head. It was six years ago and I may have confused things then or in my memory now. A provisional apology to TNP. |
Room thermostat wiring conundrum
On 18/01/2021 14:57, Dave Plowman (News) wrote:
In article , Pancho wrote: On 18/01/2021 13:15, Peter Johnson wrote: Thanks everyone for your helpful comments and advice. New thermostat now up and running. My uneducated attempt to install it did do some damage to the timer (a Drayton Tempus 7) Mine is a Drayton Tempus 6, it's time of servitude isn't over yet. I suspect you could have fixed it, but on the other hand you have a smart shiny new one and I have a dull one with a cracked plastic lid. If buying a new one I would have been tempted to look at a wifi/smart one. Do you really need the ability to control your thermostat from a mobile phone, etc? Making it more expensive and less reliable? Purely to be in fashion? Yebbut, I am a software developer, so the technology is slightly more accessible to me. Whist I appreciate this technology might not be there yet, it is useful and the actual cpu chip part of the controller should only cost pennies. Longterm/theoretically it could become very reliable. |
Room thermostat wiring conundrum
On 18/01/2021 06:54, The Natural Philosopher wrote:
On 17/01/2021 14:40, Graham. wrote: Peter Johnson Wrote in message: Well it's a coundrum to me. This is a photograph of the wiring of the existing Drayton thermostat: https://1drv.ms/u/s!AkhvgPvXD0_1jdp0...rU-7w?e=4lk9Id I'd like to replace it with a Myson device, which is wired thus: https://1drv.ms/u/s!AkhvgPvXD0_1jdp2...r-T9A?e=5zLx3L (Another picture) So what wire goes where? My first attempt to install it blew the fuse in the switch. Thanks. Red to "C" Yellow to "N.O." Insulate and do not connect the blue neutral. It depends what 'normal' means - you might want yellow to NC.... Not on a heating room stat. -- Adam |
Room thermostat wiring conundrum
On 18/01/2021 19:07, ARW wrote:
On 18/01/2021 06:54, The Natural Philosopher wrote: On 17/01/2021 14:40, Graham. wrote: Peter Johnson Wrote in message: Well it's a coundrum to me. This is a photograph of the wiring of the existing Drayton thermostat: https://1drv.ms/u/s!AkhvgPvXD0_1jdp0...rU-7w?e=4lk9Id I'd like to replace it with a Myson device, which is wired thus: https://1drv.ms/u/s!AkhvgPvXD0_1jdp2...r-T9A?e=5zLx3L (Another picture) So what wire goes where? My first attempt to install it blew the fuse in the switch. Thanks. Red to "C" Yellow to "N.O." Insulate and do not connect the blue neutral. It depends what 'normal' means - you might want yellow to NC.... Not on a heating room stat. If the cylinder stat is remote from all the other wiring it might make sense to swap cylinder stat and room stat over, and swap the ports on a diverter accordingly. Just to play devil's advocate :-) http://wiki.diyfaq.org.uk/index.php/...on es:_Y-plan |
Room thermostat wiring conundrum
On Sun, 17 Jan 2021 16:34:08 +0000, ARW
wrote: On 17/01/2021 14:26, Peter Johnson wrote: Well it's a coundrum to me. This is a photograph of the wiring of the existing Drayton thermostat: https://1drv.ms/u/s!AkhvgPvXD0_1jdp0...rU-7w?e=4lk9Id I'd like to replace it with a Myson device, which is wired thus: https://1drv.ms/u/s!AkhvgPvXD0_1jdp2...r-T9A?e=5zLx3L (Another picture) So what wire goes where? My first attempt to install it blew the fuse in the switch. Thanks. Everyone has answered this. So I'll just add make sure it was a 3A fuse that you fitted into the fused spur It was 5A, which I suspect was my doing, when I installed the previous timer, but I've been to B&Q and got a pack of 3A, so I am now compliant, and have spares. Thanks. |
Room thermostat wiring conundrum
On 18 Jan 2021 at 15:01:02 GMT, "Roger Mills" wrote:
On 18/01/2021 09:57, alan_m wrote: With no provision for a mains neutral it indicates that the thermostat is battery operated Not necessarily - although it almost certainly is. The traditional bi-metallic stat didn't need electricity to drive it. The only reason for the neutral was to provide a return for the accelerator heater - but the stat would still work if you didn't connect it. I've got a traditional one in my shower room, on a SELV circuit which wouldn't work the heater anyway. -- Roger Hayter |
Room thermostat wiring conundrum
On 18/01/2021 14:57, Dave Plowman (News) wrote:
In article , Pancho wrote: On 18/01/2021 13:15, Peter Johnson wrote: Thanks everyone for your helpful comments and advice. New thermostat now up and running. My uneducated attempt to install it did do some damage to the timer (a Drayton Tempus 7) Mine is a Drayton Tempus 6, it's time of servitude isn't over yet. I suspect you could have fixed it, but on the other hand you have a smart shiny new one and I have a dull one with a cracked plastic lid. If buying a new one I would have been tempted to look at a wifi/smart one. Do you really need the ability to control your thermostat from a mobile phone, etc? Making it more expensive and less reliable? Purely to be in fashion? Most people probably don't. But the Hive system at my holiday flat has been very useful during the Covid crisis - enabling me to see what is happening temperature-wise when I'm unable to visit. -- Cheers, Roger |
Room thermostat wiring conundrum
In article ,
Pancho wrote: On 18/01/2021 14:57, Dave Plowman (News) wrote: In article , Pancho wrote: On 18/01/2021 13:15, Peter Johnson wrote: Thanks everyone for your helpful comments and advice. New thermostat now up and running. My uneducated attempt to install it did do some damage to the timer (a Drayton Tempus 7) Mine is a Drayton Tempus 6, it's time of servitude isn't over yet. I suspect you could have fixed it, but on the other hand you have a smart shiny new one and I have a dull one with a cracked plastic lid. If buying a new one I would have been tempted to look at a wifi/smart one. Do you really need the ability to control your thermostat from a mobile phone, etc? Making it more expensive and less reliable? Purely to be in fashion? Yebbut, I am a software developer, so the technology is slightly more accessible to me. Whist I appreciate this technology might not be there yet, it is useful and the actual cpu chip part of the controller should only cost pennies. Longterm/theoretically it could become very reliable. I can see the point of a wireless stat if a new installation. But not when the cables are already there. And having a boiler which can be programmed by Wi-Fi etc. But not a stat. -- *Tell me to 'stuff it' - I'm a taxidermist. Dave Plowman London SW To e-mail, change noise into sound. |
Room thermostat wiring conundrum
On 19/01/2021 00:42, Dave Plowman (News) wrote:
I can see the point of a wireless stat if a new installation. But not when the cables are already there. I've seen many room stats placed in positions where they were easy to wire rather than in a room that you may want the most control. A wireless room stat enables the receiver to remain in the previous position and the transmitter to be moved to an alternative position in the house. My thermostat used to be upstairs in the stair well but now better positioned in the "living room" where most TV is watched and most play on the laptop occurs. And having a boiler which can be programmed by Wi-Fi etc. But not a stat. -- mailto : news {at} admac {dot} myzen {dot} co {dot} uk |
Room thermostat wiring conundrum
In article ,
alan_m wrote: I've seen many room stats placed in positions where they were easy to wire rather than in a room that you may want the most control. A wireless room stat enables the receiver to remain in the previous position and the transmitter to be moved to an alternative position in the house. I'd say if the theremostat has simply been put in the most convenient position for the installer, it won't be the only bodge in your system. ;-) -- *Verbs HAS to agree with their subjects * Dave Plowman London SW To e-mail, change noise into sound. |
Room thermostat wiring conundrum
On 17/01/2021 20:11, Roger Mills wrote:
On 17/01/2021 14:40, Tricky Dicky wrote: On Sunday, 17 January 2021 at 14:26:28 UTC, Peter Johnson wrote: Well it's a coundrum to me. This is a photograph of the wiring of the existing Drayton thermostat: https://1drv.ms/u/s!AkhvgPvXD0_1jdp0...rU-7w?e=4lk9Id I'd like to replace it with a Myson device, which is wired thus: https://1drv.ms/u/s!AkhvgPvXD0_1jdp2...r-T9A?e=5zLx3L (Another picture) So what wire goes where? My first attempt to install it blew the fuse in the switch. Thanks. The MRTE is a two wire device using batteries to power the electronics. I had a similar situation changing a previous 3 wire device to the MRTE last week. Connect the red wire (L) to C (terminal 2) in the MRTE and the yellow which will be the switched live to NO (terminal 1). You do not need the Neutral (blue wire) and will have to terminate it off either as I did with a Wago connector or a single terminal off a terminal strip. Richard For "do not need" read "*must* not connect". The blue (neutral) wire would originally have been used in a mechanical stat as the return from the accelerator heater (which reduced hysteresis). No longer used in modern digital stats. If you connect it to *anything*, it will blow the fuse under one condition or another. No-one seems to have used the magical phrase 'volt-free' which I come across in other documentation. Presumably the replacement is 'volt-free' (even though it has a battery) ?. |
Room thermostat wiring conundrum
In article , ARW
writes On 17/01/2021 14:26, Peter Johnson wrote: Well it's a coundrum to me. This is a photograph of the wiring of the existing Drayton thermostat: https://1drv.ms/u/s!AkhvgPvXD0_1jdp0...rU-7w?e=4lk9Id I'd like to replace it with a Myson device, which is wired thus: https://1drv.ms/u/s!AkhvgPvXD0_1jdp2...r-T9A?e=5zLx3L (Another picture) So what wire goes where? My first attempt to install it blew the fuse in the switch. Thanks. Everyone has answered this. So I'll just add make sure it was a 3A fuse that you fitted into the fused spur Oh come on. You know the rule. If a fuse blows - fit a bigger one and tune for maximum smoke. -- bert |
Room thermostat wiring conundrum
In article , Pancho
writes On 18/01/2021 13:16, The Natural Philosopher wrote: On 18/01/2021 11:03, Pancho wrote: FWIW the old style thermostats needed three wires. When off they put a small current though a big resistor to warm the thermostat slightly. This created a hysteresis effect and stopped the thermostat switching on an off too quickly. Er no, it was to *reduce* the hysteresis... Er no, surely you want hysteresis otherwise you get vacillation, rapid switching on an off. Having had one of these wired without the neutral by the installer I can assure you it is there to reduce the hysteresis. The old style had enough without any assistance. -- bert |
Room thermostat wiring conundrum
In article , Roger Mills
writes On 18/01/2021 09:57, alan_m wrote: With no provision for a mains neutral it indicates that the thermostat is battery operated Not necessarily - although it almost certainly is. The traditional bi-metallic stat didn't need electricity to drive it. The only reason for the neutral was to provide a return for the accelerator heater - but the stat would still work if you didn't connect it. My very old (40 yrs+) mechanical stat worked very well without a neutral. When the system was replaced about 10+ yrs ago the installer didn't bother with neutral as none was present. So I used the earth wire as neutral and performance was improved. ISTR I was advised in here that that was a bit naughty so I have since replaced it with a Honeywell battery operated electronic one which doesn't require neutral. -- bert |
Room thermostat wiring conundrum
On Monday, 18 January 2021 at 16:26:09 UTC, JohnP wrote:
"Dave Plowman (News)" wrote in : In article , Pancho wrote: This is exactly what happened to me when the boiler installer misfitted my new room thermostat. Odd, isn't it? Now most boilers have electronic control, they are still fitted by a monkey with a 'gas safe' badge. Yes - people call in a Plumber to fix a boiler! People expect an electrician to be able to fix a washing machine. What some tradesmen lack is an understanding of "Control Logic". Time Served Qualified Plumber - what does this mean - can bend and fit pipes? I recall at a place where I worked we employed "Instalation Electricians! and "Maintenance Electricians" Different aptitudes. I spent some time training service leavers to become electricians. The company I worked for also ran training courses for plumbers and they came to me for basic electrics as part of their course. The intent was to educate them sufficient to safely install (in compliance with building and wiring regulations) power supplies, bonding and controls for central heating, showers etc. On completion of their course they had a portfolio folder with all the stuff they had covered and been assessed as doing correctly at least once. They could of course forget it all when they went out of the gate ....... |
Room thermostat wiring conundrum
On 18/01/2021 16:26, JohnP wrote:
Yes - people call in a Plumber to fix a boiler! People expect an electrician to be able to fix a washing machine. It might have been common once for the same person to deal with both plumbing and electrical work. Back in the 1950s I remember seeing tradesmen advertising themselves as "plumber and electrician". |
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