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

[bernardgreen]

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?

Then ( assuming common sense applied to the design of the un-vented cylinder ) the non electrical and purely mechanical safety devices would ( should ) operate and dump water out of the cylinder. Yes that would ( and has ) create the hazard of hot water discharging somewhere outside the building where is might affect / injure people.

The trouble is that he's talking bollix

Some qualified people see the risks of putting un-vented cylinders into houses where there is no garantee the house owner will have the systems safety devices insprected and tested on a regular schedule. Is it bollix to consider the real possibility that the safety devices on an un-vented cylinder may not be tested yearly and then only when something else fails is it discovered that the safety devices are not operating to prevent ( for example ) a ruptured cylinder dumping scalding hot water.

Do qualified installers make a point of explaining this need for regular testing of the safety devices to their customers or do they only mention the ( dubious ) advantages of non vented over vented. ?

 

[Dan Robinson]

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

Yes, and it means a lot of hassle for the person doing the work as he is effectively taking responsibility for any defects he might miss. Unless he words his report in such a way that the homeowner might think he is not getting what he's paying for.

 

[Dan Robinson]

the non electrical and purely mechanical safety devices would ( should ) operate and dump water out of the cylinder

Well that's alright then.

there is no garantee the house owner will have the systems safety devices insprected

That's the owner's problem.

Do qualified installers make a point of explaining this need for regular testing of the safety devices to their customers

Yes.

 

[Nozzle]

Thanks DR, a wise caution for the other readers.. .

The plumber has been provided to me by the building firm (quite a big one in this area, many projects at once) I'll speak with the rep about the plumber. I've been waiting nearly two weeks for the guy to actually start work anyway!

Nozzle

 

[Nozzle]

Let's be honest though, in a power cut neither the burner, the stats, the igniter, the timer nor the pump will run and the system will go cold

 

[Dan Robinson]

Let's be honest though, in a power cut neither the burner, the stats, the igniter, the timer nor the pump will run and the system will go cold

Indeed, in a power cut situation, but, especially with a Rayburn or Oil fired boiler where the controls are hardly state of the art, if the installer/maintainer doesn't have the OH stats connected correctly, then the first line of defence is gone.

 

[Razor900]

Indeed, in a power cut situation, but, especially with a Rayburn or Oil fired boiler where the controls are hardly state of the art, if the installer/maintainer doesn't have the OH stats connected correctly, then the first line of defence is gone.

Exactly my point Dan.

Bernard is suggesting that faulty wiring is not an issue as the mechanical devices would provide a fall back safety provision.

Just another troll that's allowed to give bad advice to the unwary on here

 

[Nozzle]

Like it.

In my line of work, the principle is have protection but never challenge it.

(No, I don't work in porn...)

Nozzle

 

[Agile]

For those who think that safety protection always works I would remind them of the Buncefield petrol tank farm which exploded about six years ago in Herts!

 

[Nozzle]

Exactly - don't challenge your protection! Have it, ensure it is maintainable and testable, know that it is there, do not drive to it!

Nozzle

 

[bernardgreen]

Bernard is suggesting that faulty wiring is not an issue as the mechanical devices would provide a fall back safety provision.

I am not suggesting that, I am suggesting that safety and control are two separate systems involved with the safe operation of any equipment. The safety system and the control systems should not have any common parts. If a fault develops in the control system ( or is created by the installer's error ) then a separate system is necessary to ensure safety.

The safety system should preferably be part of the equipment as manufactured and not something that could be incorrectly installed on site. ( most un-vented cyclinders seem to have the safety system fitted at manufacture.

An over temperature thermal switch is part of the control system. It should not be considered as part of the safety system. It is a device which ( when not faulty ) ensures the control system cannot create a dangerous situation. As it is a device that is critical in the control system it is at least duplicated to prevent its failure creating a dangerous situation of over heated water.


***********************************
BG Your thoughts are of interest to some but not appropriate as advice.
Anyone installing or working on Unventeds must be G3 and electrically qualified, and do what those proficiencies tell him to. Period.
"Alternative thinking" will only lead to trouble. Best if you'd keep it to yourself or frame it separately.
Mod
***********************************

 

[Dan Robinson]

What YOU think is how something should be done does not mean that how it is or must be done.

Its obvious you don't understand how this all works so for the sake of people posting here asking for advice STOP contributing to subjects you are not qualified to comment on.

 

[Razor900]

Read this Bernie http://www.megaflo-unvented.co.uk/megaflo-description.php

Do you have trouble understanding words such as 'mandatory' and 'must'

Look at the three tier safety system. It clearly includes the wiring. You are a fool trying to big yourself up to people that don't know any better.

As the link proves your advice is both wrong and dangerous lets see if the mods remove your ramblings?

 

[snes]

It must be irritating for people posting for advice on here, seeking the advice of time served experts, to receive the constant intrusion of Bernard who has no qualifications here whatever.

Bernard, I mean no insult - you were presumably highly skilled in your trade and are probably the loveliest of fellows - but please leave advice to those who are qualified.

 

[shambolic]

@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.

Was involved in a case of this nature where a toddler lost 3 fingers off of one hand and 2 off the other as well as 3rd and 2nd degree burns to his chest and arms.
Was in the winter and boiler stat set to 80deg and either the 2 port for hot water was jammed in manual (after possible synchron motor failure), or wrong wiring to zone valve/cyl stat.
Full H&S investigation as it was new build site.
Lucky for our side the boiler will only do what it is told by external controls.
Unfortunately this meant 80deg C water at hot tap which toddler turned on and fell into WC sink.
That isn't the worse that can happen with poorly installed and maintained Unvented Cylinders.
Superheated steam expands by volume hundreds of times and just goes boom like one almighty bomb.