Additional Wiring for New Boiler?

[Tiggy1955]

I’m in the process of getting quotes from heating engineers to replace an old Ideal Classic LX boiler.

My dilemma I have is not so much the difference in prices quoted - I expected that - but the advice being given regards:

• what to replace it with
• the need for additional wiring or not

My initial thought was just replace like-for-like with a Standard Heat Only boiler. Most people who came to quote have recommended that. One said Standard or System boiler is OK and two said definitely a System boiler. I don’t really mind to be honest I’m looking for what is the simplest installation. Which leads me to the wiring issue.

Of the engineers who have surveyed only 2 mentioned the need for additional wiring required back to the airing cupboard (for the pump I think?). One said additional wiring is required for a Standard boiler but for a System boiler it would not be required because the pump is in the unit. The other said additional wiring is required regardless of boiler type.

I’m a bit confused, not least because none of them seemed to have assessed the absolute difficulty of running the cable!! I honestly can’t even see how it could be done given the route involves fitted wardrobes and a tiled bathroom floor.

My main issue is not with the type of boiler but I would like to know for sure if the additional cable is required or not.

At the risk of being even more confused, I would welcome any advice!

 

[ShaunCorbs]

If you go with a heat only boiler and the boiler can control the pump then yes but you may already have extra wiring at your boiler so might not need to run any extra wires so worth a check

Where’s your programmer

As for system boiler I guess there going to seal your system eg pressurise it ?

 

[SJB060685]

Where is the current pump and what motorised valve/valves do you have?

 

[Tiggy1955]

Where is the current pump and what motorised valve/valves do you have?

Hi
Pump is in airing cupboard up stairs, boiler is in the kitchen. I think the motorised valve is a basic Plumb Center one.

 

[Tiggy1955]

If you go with a heat only boiler and the boiler can control the pump then yes but you may already have extra wiring at your boiler so might not need to run any extra wires so worth a check

Where’s your programmer

As for system boiler I guess there going to seal your system eg pressurise it ?

Hi,

The programmer is directly under the boiler along with an isolation switch (as per image).

Thanks

 

[Tiggy1955]

Hi,

The programmer is directly under the boiler along with an isolation switch (as per image).

Thanks

And yes - Pressurize system, remove header tank and add filling loop.

 

[SJB060685]

If the current pump and motorised valve/valves are already in the airing cupboard then all cables needed should already be in place.
Have the installers quoting considered/suggested either weather compensation or load compensation? These control options would probably need additional wires run but as for the pump and valves you should be good.

 

[ShaunCorbs]

Hi,

The programmer is directly under the boiler along with an isolation switch (as per image).

Thanks

Does the grey cable go to the boiler and where does the white flex go ?

 

[Tiggy1955]

If the current pump and motorised valve/valves are already in the airing cupboard then all cables needed should already be in place.
Have the installers quoting considered/suggested either weather compensation or load compensation? These control options would probably need additional wires run but as for the pump and valves you should be good.

Hi,

None have suggested/mentioned load compensation.

Thanks

Pete

 

[Tiggy1955]

Does the grey cable go to the boiler and where does the white flex go ?

 

[Tiggy1955]

Ah - its at my daughters house so I would have to go round and check that tomorrow. Thanks

 

[Tiggy1955]

Does the grey cable go to the boiler and where does the white flex go ?

Here are some more images of the wiring. The grey cable comes out of the wall near the gas pipe. It is connected to the boiler control box. It appears that the yellow core of this cable is not being used!

I can't tell where the white flex is going

Thanks

 

[ShaunCorbs]

You have a spare core on the boiler wiring eg yellow which could be used for the pump overrun so you don’t need to rip all the floor boards up to run a new one

Depending on the boiler it might need a permanent live which can be taken via the fused spur below via a flex

 

[EvilDrPorkChop]

You have a spare core on the boiler wiring eg yellow which could be used for the pump overrun so you don’t need to rip all the floor boards up to run a new one

Depending on the boiler it might need a permanent live which can be taken via the fused spur below via a flex

Depends where that 3 core goes to though, might only go back to the clock below and not the airing cupboard.

If it was me, i'd go system boiler. As you'd only need Perm live, N, E, and switch live then. Where as heat only you're going to need 5 cores.