Do I need a plumber or an electrician? (Unvented work)

[Nozzle]

I'll keep the history brief, but include it to give some context..

The CH set-up before I moved in:
A modern-ish gas fired Rayburn, S plan wiring, a CH and HW zone, with vented cylinder.

Plumbing work during first extension:
Vented changed to unvented, head tank chucked away, no change (that I know of) to the electrics.

Current - second extension in progress, nothing yet installed:
UFH being added to some of the downstairs, with individual thermostats to each loop, plus some spare ports on manfold. Plumber lets me know I'll need to have an add-on timer for the UFH as it comes on earlier and goes off earlier than CH usually, plus it'll need another motorised valve

Electrician has already done first fix and have asked him to replace the CH wiring centre anyway. At this point I might as well also get him to put in a timer that handles the CH/HW AND UFH.

Something I read the other day, I think written by @Dan Robinson, was regarding thermostats on the unvented cylinder (I think it has two, but I've not taken the cover off to see). His comment got me thinking - who should I be asking to do the work?

The Plumber doesn't do electrics, he's already told me that
The sparky is capable and would easily complete the job, but perhaps unwittingly be doing un-vented work
Does the "unvented licence" only apply to the piping side of the system, and the electrics are free for all?!
Should I seek another trade, a Heating Engineer, who knows unvented, UFH & gas fired Rayburns like the back of his hand?

The plumber has been sent to me by the building firm and they obviously cannot claim to know every type of system in order to dispatch a person with the right skills AND paper, I chose the electrician as he started work months back.

Nozzle

 

[Agile]

My view is that all the electrical wiring of the safety devices on an unvented need to be done by someone with the unvented qualification.

But it seems that you are dealing with builders and not properly qualified heating engineers.

However, unlike gas, it is my belief that a G3 person can check and commission an unvented which he did not install himself.

But others here don't like me to voice my thoughts on plumbing installers who cannot connect the associated electrics.

I suppose that's why they have to work for builders. I don't!

Tony

 

[hertsboilers]

A good heating engineer should also be able to do electrical control wiring.

Some, like @Dan Robinson, even invented Tuperware, much better than me (being a qualified electrician).

 

[Dan Robinson]

I suppose that's why they have to work for builders. I don't!

Depends on the builder doesn't it.

 

[bernardgreen]

My view is that all the electrical wiring of the safety devices on an unvented need to be done by someone with the unvented qualification.

The safety devices should not rely on electrical connections. Control of the system has to be electrical but not the safety of the system.

Control can be lost during a power cut or electrical component failure but safety has to be maintained when control is lost.


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BG - It would be better if you didn't guess an answer for subjects like this
Mod
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[dilalio]

Who installed the uv? If they are G3, I am surprised they couldn't also take care of the wiring!
If he's good with heating controls then no reason why the sparks can't do the work. As long as the safety discharges and pipework to the uv are correct then the system can vent under fault conditions, which is the main thing!

 

[Dan Robinson]

My view is that all the electrical wiring of the safety devices on an unvented need to be done by someone with the unvented qualification.

The safety devices should not rely on electrical connections. Control of the system has to be electrical but not the safety of the system.

Control can be lost during a power cut or electrical component failure but safety has to be maintained when control is lost.

For Christ's sake, you're not qualified to comment, SO Don't!

 

[Nozzle]

Who installed the uv? If they are G3, I am surprised they couldn't also take care of the wiring!
If he's good with heating controls then no reason why the sparks can't do the work. As long as the safety discharges and pipework to the uv are correct then the system can vent under fault conditions, which is the main thing!

The UV was installed, and signed off, a couple of years back by a plumber associated with a different builder - I have no particular need or want to get that same plumber back in again. These new changes are to add the extra loop to the S-plan for the UFH zone, I think there's some sort of blending valve/pump associated with the UFH manifold. The UV cylinder itself is not being tinkered with this time around, but the wiring centre and programmer is. As I get the gist of it, the boiler interlocks and tank thermostat will therefore be tampered with (at the wiring centre end).

Nozzle

 

[bernardgreen]

For Christ's sake, you're not qualified to comment, SO Don't!

Just tell me exactly what was wrong with my comment about safety devices having to work irrespective of the condition of any electrical system involved.

Common sense does not involve qualifications.

If an incompetent person wires up the electrics the safety devices ( installed by a G3 qualified person ) should be able to prevent a hazardous situation developing.

 

[Nozzle]

@Dan Robinson, you ARE qualified to comment, please DO!

Or at the very least, decline to comment and leave BG to his musings I understand where he's coming from I know ther difference between principle and practice.

Nozzle

 

[Razor900]

@Dan Robinson, you ARE qualified to comment, please DO!

Or at the very least, decline to comment and leave BG to his musings I understand where he's coming from I know ther difference between principle and practice.

Nozzle

The trouble is that he's talking bollix

Yes a properly installed UV cylinder is designed to fail safe

But what if the 'incompetent person' wired the extra 2 port as a conventional system and didn't run control for the valve through the overheat thermostat? I was at one the other day that had been wired like that and they left the link in the boiler so it was heating the cylinder 24/7. That was a qualified heating engineer that didn't have his G3 quallie and didn't have a clue

Very few things found in houses are designed to be dangerous but almost anything will be if misused.

 

[Nozzle]

....which is why I've asked the question - "which trade do I need to wire it all up"?

Conventional plumbers don't do electrics.
Conventional sparkies don't do unvented plumbing.

Nozzle

 

[Razor900]

Out of your requirements it's the Rayburn that's the most specialist.

I'd look for a Rayburn specialist who has a G3 certificate which allows them to work on the UV cylinder.

Was the plumber that installed it G3 or not? Most of us will work from a fused spur onwards. He's right about the UFH needing to be on an S plan plus - best make sure there's a bypass though

 

[Nozzle]

Razor900, thanks for the info - I'll look into it. The plumber who installed the UV I don't think was G3, as he got someone else in to sign it off - I must assume because of the G3 papers. I have the service record for it with the signatures. The programmer and wiring centre was the same unit before and after installation of the UV though I don't know if the wiring centre was adapted. The previous vented cylinder had a thermostat so can assume no new cable was required.

The Rayburn looks like a fairly standard gas burner inside the housing, it just has fancy doors on it and a large hunk of iron bolted to it! The burner is a Honeywell Type V 4600 T if that is anything you recognise.

As a pro installer yourself, have you ever been called out just to verify an installation is okay when a punter like me is unsure whether the installation is adequate?

 

[Dan Robinson]

Conventional plumbers don't do electrics.
Conventional sparkies don't do unvented plumbing

The simple solution is find a plumber that can cope with electrics.

The safety devices should not rely on electrical connections

What like the overheat stats? Of which, depending on cylinder can number 4. They need to be connected properly.

@Nozzle, it is great that you understand, but sadly it is not just you that reads Bernard's often stupid advice. Someone might not understand and plod on thinking "ah, he's a free thinker he must be right."