Central Heating Clock/timer

[yorkiejohn]

At the moment we have a Horstmann 425 Coronet with the electrical supply running up from a double socket, we are replacing it with a Horstmann Channel Plus H17XL series 2 plug in direct replacement. Can I do a straight swap with the wiring as it is or would I need to put a fused connection unit in ?

 

[oharaf]

I think an FCU is a good idea and i'm sure a read this week that this should be the case.

Protection and safety can never be to important

 

[Taylortwocities]

A plug and socket is a perfectly adequate isolator and is noted in BS7671 as such. By all means put in an FCU if you want.

Both for the plug and for the FCU option, make sure that the fuse is at the correct rating - 3amps is usual for boiler circuits - otherwise you may find that the programmer becomes a very expensive fuse!

 

[securespark]

At the moment we have a Horstmann 425 Coronet with the electrical supply running up from a double socket

Is that a fused supply, or does it come off the back of the socket?

 

[bengasman]

All electrical connections for a boiler should come from one source, fused at 3 amp and if it is a socket, it MUST be unswitched. There are unswitched double sockets on the market, but they are pretty rare. Having separate sources for the timer and the boiler is a really bad idea. Gas, water and electricity coming together in one appliance, not something you want to experiment too much with.

 

[jpdw]

There are unswitched double sockets on the market, but they are pretty rare. Having separate sources for the timer and the boiler is a really bad idea. Gas, water and electricity coming together in one appliance, not something you want to experiment too much with.

I thought of doing exactly this for approximately 10 seconds till I realised this would be a very bad thing....
Never mind the gas & water & electric all-together issue, powering the controller from one socket/spur and the boiler (often a long way away) from another would leave serious danger of some one turning off "the system" at one point only to get a shock (literally) finding out it's still live & fed from somewhere else!

That said, I dont think the OP has indicated any 2nd power feed (or have a missed something?).

All electrical connections for a boiler should come from one source, fused at 3 amp and if it is a socket, it MUST be unswitched.

I'm just curious... why must it be unswitched ? Obviously you dont want it accidentally turned off but why is this mandatory esp given there is always some way to isolate the system.

 

[bengasman]

Not quite sure why the socket must be unswitched, I presume there is some theoretical issue that makes an unswitched socket much safer. Greater minds than mine have figured this out. Probably the same guy that figured out that it is okay to leave a system with inadequate bonding as it is and not tell anybody apart from the occupier but if you upgrade it, you have to do all that is required to bring it up to today’s standards. So if due to access problems a complete bonding job would be £400 and not affordable, whereas doing 80 percent of the job would be £50 and inside the budget, you are not allowed to do that; the full job or nothing. In other words, you can not make it safeR. You make it fully safe or leave it completely dangerous.

 

[jpdw]

Not quite sure why the socket must be unswitched, I presume there is some theoretical issue that makes a switched socket much safer.

Heyup... are you not contradicting yourself a bit ?

you seem to be saying:
* socket must be unswitched
* switched sockets are much safer

 

[bengasman]

Without prejudice, just typo. One can argue long and hard about what is safer, switched or unswitched. The only thing that is sure, is that switched is not allowed to feed a boiler. You could also argue that one can not argue as it takes at least two to argue, however my ex would argue that.

 

[gas4you]

Only reason I can think of why it has to be unswitched, is so that you have to remove the plug to isolate the boiler. This is then a double pole isolater, rather than just the live being disconnected in a switched socket.

Please correct me if this is wrong as I would like to know as well if not