Thoughts on commissioning a Vaillant Arotherm Plus 12kW

[sharpener]

18 minutes ago, JamesPa said:

I'm pretty sure plumbers connect these up if they choose to, and I'm pretty sure there is no regulation that says it has to be an electrician, its just connecting to an existing circuit via the 'wiring box'.  But then again that's why I still think an electrician may turn up and disagree with the current installation!

 

Both my potential installers had their own electrician and I gathered this to be the usual practice. (The ppl who in the end did the job are actually a firm of electricians who specialised in heating systems and then took on their own plumbers.) He turned up for a recce the previous week which was useful as we could sort out the final details without the other trades on site or any time pressure.

 

22 minutes ago, JamesPa said:

I'm pretty sure plumbers connect these up if they choose to, and I'm pretty sure there is no regulation that says it has to be an electrician, its just connecting to an existing circuit via the 'wiring box'.  But then again that's why I still think an electrician may turn up and disagree with the current installation!

 

Not sure what you mean by "wirng box". The CU they fitted has a B6 mcb for the electronics indoors - the 13A socket for the VR940F internet interface has been labelled as you can only draw 6A from it - and a C32 mcb for the 4sq mm feed to the mandatory AC isolator on the outside of the house, did your man install that already?

 

30 minutes ago, JamesPa said:

There is a switched fused spur and typical heating wiring where all the electronics will be

 

... but reckoned to be good practice to have them both on the Type B RCD that is specified in the MIs. It does not matter if either is energised when the other is not, so an indepent supply is I suppose OK if yr spur box is on a dedicated boiler cct, I would not want it on a general ring main though. Maybe I am not fully understanding your setup.

[JamesPa]

10 hours ago, sharpener said:

Not sure what you mean by "wirng box". The CU they fitted has a B6 mcb for the electronics indoors - the 13A socket for the VR940F internet interface has been labelled as you can only draw 6A from it - and a C32 mcb for the 4sq mm feed to the mandatory AC isolator on the outside of the house, did your man install that already?

By 'wiring box' I mean one of those typical central heating 'wiring centres' that many use to do all the interconnections between thermostat, valves, call for heat for the boiler etc.  Not necessary so far as I can see for the Vaillant, or indeed most ashps, as almost all wires go back to the ashp control, unless you are doing something silly with external controls (which I'm not).

 

Yes the ac isolator is fitted and wired already.  Actually a 32 A one with a 6mm feed (but a 16A MCB) just in case it needs to be upgraded in future.  I put the cable in, sparky fitted the isolator and connected to the cu.

 

10 hours ago, sharpener said:

but reckoned to be good practice to have them both on the Type B RCD that is specified in the MIs

They are.  The current boiler is run off the ring main.  I'd ideally prefer to have it separate as we do get the occasional nuisance trip, but not worth the effort until I replace the cu for some other reason.

Edited November 1 by JamesPa

[sharpener]

5 minutes ago, JamesPa said:

Not necessary so far as I can see for the Vaillant, or indeed most ashps, as almost all wires go back to the ashp control, unless you are doing something silly with external controls (which I'm not).

 

No but may provide a handy route to previous boiler or tank location if that is where the new cyl is going to be, saved me some awkward cable runs.

 

9 minutes ago, JamesPa said:

Yes the ac isolator is fitted and wired already.  Actually a 32 A one with a 6mm feed (but a 16A MCB) just in case it needs to be upgraded in future.  I put the cable in, sparky fitted the isolator and connected to the cu.

 

Sounds like you are good to go then apart from wiring the e-bus and SensoComfort itself. Best of luck!