Undersink point of use water heater

[cantaloup63]

I wish to install an undersink point of use instant water heater in a house that I rent out due to the long distance between the combi boiler and the kitchen sink. For what I need, something about 3kW will suffice, and I will get an electrician in to connect this up according to whatever regulations apply.

I am quite adept with plumbing. Do I need any form of certification for the wet work, or is it a job within the bounds of a DIY'er?

 

[Boilerman2]

A 10 Litre 2Kw heater will serve a kitchen sink perfectly and as is under 15 litre capacity is out of the scope of Unvented storage water heaters G3,
however you will have to abide by WRAS and of course Electrical Regs Part P
a good heater would be the Arisotn EU10 wqhich is around £130 +vat which is FAR cheaper than a Heatrae Sadia Multipoiint which is more than twice the price!!

 

[cantaloup63]

Boilerman, you are a gent and a scholar. I take it that it will need the usual expansion tank kit (we have already fitted a prv to the main supply to the house to get it below 6 bar to protect some electric showers). Will any kit suffice or does it have to be one recommeneded as per MI?

 

[Boilerman2]

a 2 Litre expansion vessel (white) for potable water will be required
the Safety valve comes with the Ariston heater, this will need to be run to a tindish and then to low level outside

 

[Agile]

A 10 Litre 2Kw heater will serve a kitchen sink perfectly and as is under 15 litre capacity is out of the scope of Unvented storage water heaters G3,

Are you sure that you have kept up to date with the current regulations?

 

[cantaloup63]

A 10 Litre 2Kw heater will serve a kitchen sink perfectly and as is under 15 litre capacity is out of the scope of Unvented storage water heaters G3,

Are you sure that you have kept up to date with the current regulations?

And so the answer is what precisely Agile? May I or may I not legally do the wet side of this installation?

 

[Boilerman2]

Please accept my apologies if I amn wrong, but as far as I know water heaters of less than 15Litres capacity do not fall into the remit of G3, of course WRAS has to be complied with!

 

[cantaloup63]

It's been a while, but WRAS involves avoiding wastage of wholesome water, preventing contamination etc. Or is there something more sinister I'm overlooking

Also, this tundish running to low level - the sink in question is at the top of a tall old victorian house hence the current pipework connecting the tap to the boiler in the cellar is highly wasteful and of poor design. Is there such a thing as an in-line sealed tundish which could then be run into the existing wastepipe under the sink?

 

[Agile]

CHANGES TO BUILDING REGULATIONS – G3

Some of you may be aware that earlier last year Part G of the building regulations was updated. However engineers may not be aware that VENTED cylinders are now covered by this update along with unvented.
The 15 litre limit previously adopted has also been removed so that all unvented cylinders now come under G3.

The fact that vented cylinders are now covered by G3 means that it is not permitted to install a vented cylinder without the appropriate safety controls that are commonplace with unvented cylinders. There is no requirement to hold certification to install/service or commission a vented cylinder, and they do not require notification. However they all must be installed in accordance with the current regulations.

The building regulations are all available as a free download from the Planning Portal website for you to look at and study:

http://www.planningportal.gov.uk/buildingregulations/approveddocuments/downloads

Alternatively attendance on an Unvented course will provide you with the knowledge and understanding
about the controls, which can then be adopted for use with a vented cylinder

 

[cantaloup63]

Thank you Agile. I shall read part G and then review my level of competence. It may well be worthwhile paying to get someone in who can do both the plumbing and electric side.

Can anyone recommend someone in Chiswick/Ealing area of London, where my rented property is, and give a ballpark figure to supply and install (I would rather not have one that requires a hard rewire back ti the CU, and a 3kW plug may well suffice)?

Edit - section G3 does indicate that units under 15L are likely to comply with the regs, so this is now a matter of checking the MI's. The Tundish arrangement is a new one to me and will need some further consideration, although there is a metal hopper up there with a metal downpipe which chould do the trick if I can get a ladder up there.

 

[cantaloup63]

Bump - I'm looking to employ someone to do this since I don't fancy the ladder work. Anyone interested or know of someone in West London who can supply, install and commission?