No switched live to boiler?

[SimonG]

In cases like this I tend to go in, identify all the inputs and then disconnect everything before starting from scratch.
Then I know it's right.

 

[Basher]

Grand so, that's the way to do it alright.

Does the boiler still need a permanent live though as well as the (proposed) switched live, most boilers do for overrun etc.

Yes, that is the proposal.
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You are right Basher, the orange ones are on 10! And of course I could check whether there is voltage on 10 (I am just a bit reluctant to open an electric panel before switching off supply, I never usually do that...), although I am totally convinced that there is, following all the logic of a standard S-Plan. But the voltage on 10 is not taken anywhere, so I am now convinced that the solution would be to connect terminal 10 on my S-Plan wiring to the Switched Live terminal on my boiler (x2 connector no 1 on the Intergas Compact HRE). Question 1: Would you concur from what you can see?
I have also thought about how the UFH zone valve could be brought into play, as this valve is directly connected via L, N, E, only to the UFH wiring centre. If I connected the grey wire from this valve (currently unused) to terminal 1 permanent live (alongside the grey wires from the other two valves), and the orange wire (currently unused) to Terminal 10 (alongside the orange wires from the other two valves), I believe that the microswitch in the UFH zone valve would close when the valve is activated, and provide a live to the no 10 terminal, just as the other two valves do via their orange wires. Question 2: Does this make sense to you?
I have read the boiler instructions, and connecting one wire from the wiring centre to one connector in the boiler is a 5 minute job. No other wires would have to be changed. I may have to take out the link between 6 and 7 on the x4 connector, which I believe makes the boiler think that it needs to be permanently on. I would obviously do this with the power supply turned off. This should then result in the boiler coming on and off when valves are opening or closing. Question 3: Does this make sense, and would this require any other setting change to the boiler?
Thanks for all the help, it is all clear in my head now, would just appreciate some additional views!

Hi Cheshire
The consensus seems to be that what you described earlier is the way to go.
ie get electrician to:
Replace present 3 core cable to boiler with 4 core to carry both a perm live, and a switched live from terminal 10
wire UFH valve grey wire to live
wire UFH valve orange wire also to term 10 (there may be a spare core to implement that?)
job done!

 

[CheshireH]

OP .. you seem to have made up your mind what you are going to do so crack on with the bang test

AND you shouldn’t have 2 points of supply to your central heating system - it tends to irritate the guys who service them as they don’t like getting shocks ..

I think I will rather continue to seek advice than do a bang test - very grateful for the hints and tips, which is exactly what helped me discover the two point of supply issue. It was not me who wired it up in the first place!
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Yes, that is the proposal.
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Hi Cheshire
The consensus seems to be that what you described earlier is the way to go.
ie get electrician to:
Replace present 3 core cable to boiler with 4 core to carry both a perm live, and a switched live from terminal 10
wire UFH valve grey wire to live
wire UFH valve orange wire also to term 10 (there may be a spare core to implement that?)
job done!

Indeed, all of that, plus I believe replace power supply to UFH valve with power supply from wiring centre (solving the two supply source issue, I do think this needs to be done for safety), and use cable between UFH wring centre and S-Plan wiring centre to connect to boiler enable on the UFH wiring centre, wiring it into S-Plan like a thermostat for another zone.
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Regarding power supply: I noticed that switching the boiler feed off near the boiler does not switch off the power to the central heating and hot water programmer (which is in the kitchen). Clearly the programmer is connected as without a live signal from it nothing central heating and hot water would not work. If the programmer is still on when the boiler feed is disconnected, does this not mean that the wiring centre may still get a live feed?
I might be wrong here, but if not, I am starting to wonder how this was all signed off - which it was, I remember the electrician going round for almost a day with another electrician who certified it all.
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I had a look into all the wiring today, including inside the boiler. All as expected and supporting the solution above. However, this also confirmed that the power supply to the programmer is indeed made locally in the kitchen (same consumer circuit breaker, but not isolated by boiler switch). So a live feed could be sent even when boiler switch is off. Luckily I isolated the consumer unit circuit breaker at all times when investigating the system.
The cable running from programmer to S-Plan wiring centre is only three core plus earth. So if I wanted to supply power to the programmer from the S-Plan wiring centre as it should be done, I could not run a neutral wire. In this context, would it be acceptable to use the neutral from the local supply?

 

[Basher]

the dreaded 'borrowed neutral'
before answering, I wondered what model the programmer Is, and how it is wired. If it just switches the wiring centre via 'volt free' contacts with the live coming from the wiring centre and returning via the appropriate core, there would not be a hazard in the way you describe.

 

[CheshireH]

the dreaded 'borrowed neutral'
before answering, I wondered what model the programmer Is, and how it is wired. If it just switches the wiring centre via 'volt free' contacts with the live coming from the wiring centre and returning via the appropriate core, there would not be a hazard in the way you describe.

It’s a bog standard one, mine is iflo but the Drayton ones look identical. Definitely not volts free...it is the live feed going through for CH and HW. I am puzzled how this could be wired up like this only two years ago. As I said, luckily I removed circuit breaker before looking at wiring and did not touch anything before building up a through understanding, but the wiring centre could definitely be receiving a live feed from programmer even when boiler switch is off!

 

[Basher]

That is a pain. I agree you need another wire!
The system should have been done to the wiring regs, so I don't understand why you've ended up like this, unless due to 'organic growth' of the heating.

The 'borrowed neutral' is not the proper way as I'm sure you appreciate. In this instance it would work because both loads are on the same breaker, but not recommended - those more knowledgeable might like to comment?

Would it be practical to move the programmer to be nearer the wiring centre?

Alternatively if you were considering updating the system, eg to control individual radiators, then wireless could solve the issue.

 

[CheshireH]

Thanks Basher, I am not going to pursue the borrowed neutral idea. I am not quite knowledgeable enough to really understand why this would be problematic, but it would certainly be confusing.
I will indeed go wireless for the heating control, which would leave me with a spare wire to the boiler wiring centre to connect the neutral correctly for the hot water control. Most probably, I will even move the entire programmer to the garage next to the boiler, we do not really need to access hot water controls all the time, this runs on a timer and rarely gets changed. And my wife would rather like an extra socket in the place of the apparently very ugly programmer, and the fact that the programmer is locally supplied, with power not linked to the boiler, will allow this to be done!
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Deciding whether to move and keep the programmer next to the boiler and keep a manual on/off option available or go wireless and just connect the wireless receiver. I will be using a Lightwave RF boiler switch (as I have loads of Lightwave TRVs already) for CH, but not sure what to use for HW. Thinking of a wireless relay but worried about no manual override option. Any ideas?

 

[Basher]

Deciding whether to move and keep the programmer next to the boiler and keep a manual on/off option available or go wireless and just connect the wireless receiver. I will be using a Lightwave RF boiler switch (as I have loads of Lightwave TRVs already) for CH, but not sure what to use for HW. Thinking of a wireless relay but worried about no manual override option. Any ideas?
[/QUOTE]
No immediate bright ideas. It's a shame Lightwave don't do a combined heating and HW link. There are other brands doing this, but I guess would't integrate with what you're suggesting.
I used a Lightwave electric switch LW934 to control a water heater, and scheduled it with the app, but that won't integrate with a Lightwave thermostat controlling the boiler switch. And the boost button would be your phone!

If you decide to put a 13A socket where the programmer is (make sure the cable is 2.5mm) don't you then have a spare 3 core to the boiler wiring centre? In which case you could buy an electronic boost button and hard wire it! This sort of thing: Sangamo Powersaver Electronic Boost Timer 30min to 2 Hour - https://www.tlc-direct.co.uk/Products/SGPSB.html . I understand if this doesn't appeal!

 

[CheshireH]

I used a Lightwave electric switch LW934 to control a water heater, and scheduled it with the app, but that won't integrate with a Lightwave thermostat controlling the boiler switch. And the boost button would be your phone!

Oops, why does it not integrate with boiler switch/thermostat? I just put a saved search on eBay for the LW934 as it is no longer sold anywhere. Is it not just like a timed switch that you can schedule, activate via app, or indeed press manually?

 

[Basher]

Oops, why does it not integrate with boiler switch/thermostat? I just put a saved search on eBay for the LW934 as it is no longer sold anywhere. Is it not just like a timed switch that you can schedule, activate via app, or indeed press manually?

it does all those things - schedule, activate by app, and press manually, yes. Sorry, the integrate comment is misleading - I was thinking you might want to 'talk to it' via the boiler switch/thermostat.
The one thing about it, is that it has a temperature sensor, and turns off once the set temp is reached. It goes up to 40 or 45 deg C. So if you set it to max, the room never gets to that temp. so it continues switched on until the schedule activates 'off'.
I've got an unused LW934 if you want one! It was one of the few first series Lightwave devices which were Homekit compatible. I hope they don't stop supporting it.

 

[Ziggie]

Know nothing but taking a flier, the U.K. orange wires go to 10 . Why don’t you take the wires out of 10 and see if the boiler fires taking due care with 240 volts . I always with loose wires pop them into Wago connectors.
but read below first
If the boiler fires when the valve is closed then there is a feed from the valve directly to the boiler (possibly from another position.

if the boiler doesn’t fire, then something I’d connecting 10 to the boiler.


my system (y type) connects using 4 core to provide both LNE and switched live ( using a yellow core which nearly looks orange)

could it be that one orange is actually the switched live to the boiler?

this could explain that you need to put on one valve manually.

you say you have 3 valves - where is the 3 orange?

Probably a load of rubbish but you never know!

 

[CheshireH]

Good evening, I implemented everything that was discussed in this thread, but my last step, connecting a switched live to the boiler from where the orange cables terminate, is failing. I installed a new cable with four cores to the boiler today, and I connected the switched live from the oranges in the S-Plan wiring centre to terminal 1 on the x2 connector. I also removed the link between 6 and 7 on the x4 connector as per the Intergas manual. The boiler fired up just fine, ran for a while, but after about half an hour suddenly all power to the boiler and to the new hot water switch (fed by same mains power) was cut out. I removed and reinstalled the same fuse, and funnily enough (I cannot explain this at all), the power was back, and the same thing happened again, half an hour of running and then the power cut out again. Just the power feed to the boiler on the fused spur. I then suspected the spur switch and replaced it with another one. No joy, by now things would not start up again at all. I then removed the power to the boiler from the wiring centre - power was back when I put the circuit live again. I reconnected the boiler, and power cut out again immediately...Interestingly, the fuse is not blown. I tried various fuses in the process, so it was not down to one specific one. How can the power to the entire wiring centre be cut, with the fuse remaining operational?

I now returned everything to the original state, no switched live and reconnected 6 and 7 on the X4...

Can anybody make any sense of this?

Thanks, Henrik

 

[Murdoch]

I reconnected the boiler, and power cut out again immediately...Interestingly, the fuse is not blown. I tried various fuses in the process, so it was not down to one specific one. How can the power to the entire wiring centre be cut, with the fuse remaining operational?

What is tripping? MCB? RCD?

 

[CheshireH]

What is tripping? MCB? RCD?

Nothing is actually tripping. The fuse in the spur is also intact. Just a ll the devices connected to the spur stop working. Last night, I fully disconnected the boiler, other devices were fine again. Then I put everything in the boiler back to the state it was in before (6,7 connector on x4 back in, removed switched live from 1 in x2), and connecter it all into the wiring centre in the same places as yesterday. Now the boiler is running again, in the old (non-switched) manner. I just cannot explain at all why other devices lose mains power, too, without anything actually tripping...

 

[Basher]

Nothing is actually tripping. The fuse in the spur is also intact. Just a ll the devices connected to the spur stop working. Last night, I fully disconnected the boiler, other devices were fine again. Then I put everything in the boiler back to the state it was in before (6,7 connector on x4 back in, removed switched live from 1 in x2), and connecter it all into the wiring centre in the same places as yesterday. Now the boiler is running again, in the old (non-switched) manner. I just cannot explain at all why other devices lose mains power, too, without anything actually tripping...

Could it be a dodgey connection? Maybe a bit of sleeving slightly under a screw terminal somewhere? Otherwise needs diagnosis with a tester or multimeter when it's in 'fault' mode!

 

[CheshireH]

This is a possibility of course, but I am trying to understand the logic...Why would there be no more feed to the hot water switch if the boiler connection was 'dodgy'? Why did the 3 AMP fuse not blow (get destroyed)? Could a short circuit of some kind create a scenario in which this could happen?

 

[Basher]

This is a possibility of course, but I am trying to understand the logic...Why would there be no more feed to the hot water switch if the boiler connection was 'dodgy'? Why did the 3 AMP fuse not blow (get destroyed)? Could a short circuit of some kind create a scenario in which this could happen?

Sorry I wasn't suggesting there was anything wrong with the boiler connections. I was thinking more of the mains supply to the spur, and wonder if anything had been disturbed during removal of the original programmer, unless I have misunderstood the extent of your upgrade.

 

[Murdoch]

Just remember it may be live and the issue is with the neutral

 

[John.g]

Nothing is actually tripping. The fuse in the spur is also intact. Just a ll the devices connected to the spur stop working. Last night, I fully disconnected the boiler, other devices were fine again. Then I put everything in the boiler back to the state it was in before (6,7 connector on x4 back in, removed switched live from 1 in x2), and connecter it all into the wiring centre in the same places as yesterday. Now the boiler is running again, in the old (non-switched) manner. I just cannot explain at all why other devices lose mains power, too, without anything actually tripping...

What do you mean by the non-switched manner?, is the boiler now stopping/starting from the programmer/mid position valve in all modes or have you a permanent live from somewhere and the boiler is permanently on just starting/stopping on its boiler stat?.

 

[SJB060685]

How were you testing for a feed? With a multimeter? Sure you've not lost a neutral somewhere?

 

[CheshireH]

What do you mean by the non-switched manner?, is the boiler now stopping/starting from the programmer/mid position valve in all modes or have you a permanent live from somewhere and the boiler is permanently on just starting/stopping on its boiler stat?.

Permanent live - as I had before. The idea was to introduce a switched live, of course, plus some other upgrades (wireless controllers etc. - which all work fine).
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How were you testing for a feed? With a multimeter? Sure you've not lost a neutral somewhere?

So far I have not tested with a multimeter - I do not really like opening the wiring centre when the power is on. So it could of course be a neutral connection. If I 'lost' one neutral (say the boiler neutral, which was the latest change when I swapped from 3 core to 4 core cable, was 'dodgy'), could that cause other devices attached to the spur to stop functioning (even though they worked fine before)?

 

[John.g]

Can you connect say a 100W test lamp or bulb across the switched live in the wiring centre and switch between the three different modes and see what happens.

 

[CheshireH]

Alternatively (even though I cannot see how this could have happened), if the newly attached neutral wire somehow touched any live wire, all neutral would be live in the neutrals block, which I assume would stop anything from working? Is that correct? Should this not trip the RCD or consumer unit fuse?
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Can you connect say a 100W test lamp or bulb across the switched live in the wiring centre and switch between the three different modes and see what happens.

Yes, I can do that once I am convinced that it is now working OK again without the switched live - as mentioned I reconnected everything this morning so I may have eliminated a 'dodgy' connection. Boiler has been running fine all morning in permanent live mode.

 

[SJB060685]

This really needs to be tested with a multimeter and by someone experienced. If you lost a neutral or have a dodgy connection at the boiler then the boiler won't engage, likewise if there was a dodgy connection in the wiring centre it will have the same affect on all system components. As Murdoch said above the live/lives could well be carrying full voltage but without a neutral there is no loop created and no function of components.
The only real way to test this is with a multimeter, checking for 230 volts between live and neutral and live and earth, not with a terminal screwdriver I suspect you've used?

 

[CheshireH]

This really needs to be tested with a multimeter and by someone experienced. If you lost a neutral or have a dodgy connection at the boiler then the boiler won't engage, likewise if there was a dodgy connection in the wiring centre it will have the same affect on all system components. As Murdoch said above the live/lives could well be carrying full voltage but without a neutral there is no loop created and no function of components.
The only real way to test this is with a multimeter, checking for 230 volts between live and neutral and live and earth, not with a terminal screwdriver I suspect you've used?

I do have a multimeter, I am not taking any chances with electricity. But so far I never even had the wiring centre open when the power was (supposedly) on. I understand what you are saying about the voltage, even without any component operating.

My new wiring centre has connector blocks for neutral and earth that are connected via small 'paper clip' metal connectors. I am wondering whether they are reliable? I did not like them when wiring things up, as I wanted to use insulated ferrules everywhere, but I could not get the ferrules into the connector blocks alongside the 'clips'. So my neutrals and earth are connected with bare wires. I am thinking about redoing the earth and neutral blocks with proper cable connection between the terminals in the respective blocks?

 

[SJB060685]

@Murdoch can you explain to him the requirements in this case. My understanding is any wires or links should be of suitable size and insulated. If not then I can see potential arching, which would obviously cause things to trip as well as potential fire hazards.

 

[CheshireH]

@Murdoch can ypu explain to him the requirements in this case. My understanding is any wires or links should be of suitable size and insulated. If not then I can see potential arching, which would obviously cause things to trip as well as potential fire hazards.

I would appreciate this. The wiring centre which I purchased is a Danfoss WC4B which is purpose made for S/Y-Plan wiring, and the small clips in the neutral and earth blocks came pre-installed.
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These are the paper clip style connectors I am referring too. I managed to get the insulated ferrules in on this example using the old wiring centre, but I was struggling in the mix of all cables to fit them in. Could try again if the paper style clips are ok to use, otherwise I could use the double entry ferrules (example on right) to add little 1mm wire connectors between the terminals?

 

[SJB060685]

Those links are supplied with the wiring centre and are already in place for how the wiring should be done. They are ok but all other wires should be insulated.

 

[CheshireH]

Those links are supplied with the wiring centre and are already in place for how the wiring should be done. They are ok but all other wires should be insulated.

All wires are insulated and fitted with insulated ferrrules. Links between Live terminals are made with 1.5mm insulated links. It is just the earths and neutrals that are fitted without ferrules, alongside the 'clip links'.

 

[Murdoch]

My advice is to stop meddling and pay somebody ........

 

[CheshireH]

My advice is to stop meddling and pay somebody .

I started 'meddling' because I paid somebody who fed two live feeds into the wiring centre that were not isolated by the boiler switch, left the messiest of wiring centres and did not include a switched live to the boiler. I appreciate the advice not to take risks with electricity, but I do find it very helpful to understand what is going on, even if I then ask somebody to implement. Thanks for all the help so far!

 

[CheshireH]

Just wanted to report that things are now working fine. I rewired everything, adding another neutral and another earth connector block linked to the existing ones, so that no wires are doubled up on any earth or neutral connector. All wire ends are now terminated in isolated ferrules. I tightened all connections carefully. I checked for the correct signal on the switched live with a multimeter, before connecting switched live to the boiler.

The problem on the last step must have had to do with a poor connection. I read up a lot on possible issues, but I simply cannot explain my scenario: It all worked fine, I then did nothing else than adding a new boiler cable with switched live included, it started off fine until suddenly all components stopped. There was no issue with the power supply from the mains. Same scenario again twice after - starting up fine then switching off all components. Eventually, even removing the boiler live did not fix it. I ended up removing the boiler cables altogether, and then connected them again without the switched live. I do not think however that the addition of the switched live was in any way relevant, as it works fine now in exactly the same wiring constellation.

If anybody has any further input on what kind of poor connection and scenario could have caused this failure, it would certainly make me feel much better, and might help others who may read this thread in the future!

Thanks again for all the advice. Fingers crossed, but it looks as if I now have a safer set-up, with no more external live feeds that are not isolated by the boiler switch coming into the wiring centre from programmer and UFH controller, plus the addition of wireless switching of all components!

 

[Ben-gee]

A common one is that you insert a wire slightly too far and do up the terminal screw on the insulation/bare metal border - this causes intermittent faults...