Perm and switched live to new boiler?

[pmx_super]

Had a plumber round to quote for a new boiler. He observed that my old boiler only had a switched live connection, but that a new modern one would require a perm live as well. The problem then became how to run a new cable from the control unit in the airing cupboard (with the HW cylinder) upstairs to the boiler downstairs.

The boiler he suggested was one a Glow-worm Flexicom:
http://www.glow-worm.co.uk/products/open-vent-boilers/flexicom-hx/

but I observe that the Ultracom comes with an inbuilt digital programmer:
http://www.glow-worm.co.uk/products/open-vent-boilers/ultracom-hxi/

Do these built-in programmers do everything that separate time controls would do? Would this therefore remove the need for any power cables running from the airing cupboard to the boiler? If so, how would you then connect a HW thermostat to it - would that require a cable? Can you connect wireless room-stats to it as you can some of the separte controllers?

 

[Ronald0]

Where is your Isolator (3amp double pole) switch? Is it next to the boiler?

If so, take the permanent supply from there.

 

[stem]

Older boilers had a 'switched live' only, that when the controls (thermostat / motorised valve(s)) called for heat it became 'live' and the boiler operated. Switch off the live, and the boiler goes off.

Newer boilers have facilities such as a pump run-on facility, that need to be powered when the switched live has gone off, hence the need for the additional permanent live. Selecting a boiler with in built controls will not negate this, how do you think the programmer will be powered without a permanent live supply?

I believe there are some boilers out there that don't need a permanent live, but I can't think of one off hand.

 

[Terrywookfit]

You would need 4or 5 additional cables with a built in programmer!

 

[pmx_super]

Ok, my understanding is improving!

So couldn't they just spur off one of the many power points in the kitchen (where the boiler is) instead of running a spur off the isolator in the airing cupboard?

Terrywookfit - why would I need more additional cables with a built in programmer?

 

[stem]

No, it must be from the boiler FCU for correct fusing and isolation. These should also be an isolator next to the boiler for isolation during servicing if the FCU is remote

If your new boiler had a built in programmer, the cables going to the existing programmer would need re routing to the boiler.

I don't want to add to your woes, but what is the pump presently connected to? If it's wired to a wiring centre in your airing cupboard, that too will need connecting to the boiler wiring terminals, as the boiler will control the pump.

 

[D_Hailsham]

So couldn't they just spur off one of the many power points in the kitchen (where the boiler is) instead of running a spur off the isolator in the airing cupboard?

It's advisable for the heating electrics to be fed from one source so that, when you disconnect at that point, you know the whole system is dead. If you take the boiler supply from the spur but take the pump, motorized valve(s), programmer etc from a point in the airing cupboard, there is a danger that someone will forget about this and get a shock when they work on the boiler.

Terrywookfit - why would I need more additional cables with a built in programmer?

Connections to valve(s), pump, cylinder thermostat, room thermostat.

How many wires run from the airing cupboard to the boiler at the moment and what are they connected to at the boiler end?

 

[pmx_super]

Terrywookfit - why would I need more additional cables with a built in programmer?

Connections to valve(s), pump, cylinder thermostat, room thermostat.

How many wires run from the airing cupboard to the boiler at the moment and what are they connected to at the boiler end?

Aha, I suspected as much. Currently only one wire - switched live - runs to the boiler.

 

[transam]

As I understand it there would be a problem getting enough wire's to the new boiler ??? in order to facilitate the pump over run ?? e.g pump live , permanant live ??? in which case ????

 

[sambotc]

Think the baxi solo can be used without a P/L.

 

[londonboy]

Think the baxi solo can be used without a P/L.

You think correct

Are you sure theres no way of getting a 5 core in?? Conduit on the outside?

 

[transam]

In which case how about a pipe stat in airing cuboard ??? seen this done a few time's , wether the boiler manu' would were it , u could ask ????

 

[D_Hailsham]

What components do you have in your airing cupboard?

 

[transam]

What components do you have in your airing cupboard?

Sorry if I am misunderstanding but?? Is that question for me , or the O.P ???

 

[D_Hailsham]

What components do you have in your airing cupboard?

Sorry if I am misunderstanding but?? Is that question for me , or the O.P ???

It was aimed at the OP.