under sink water heaters i havent a clue?

[thekingiam]

pricing up a job and they want under sink water heaters in kitchen and bathroom but they want me to supply them.
not being a plumber i tried investigating on interweb and got confused with the jargon vented non vented etc.
can someone recommend any?

 

[thekingiam]

maybe i will try the plumbers forum?

 

[ayjay]

it needs a plumber to install them so best ask on their forum
i think the w/heaters that go on the wall above the sink are open vent the ones under are closed/ mains pressure

 

[JulianC]

Both vented and unvented are available in under and over sink formats. Vented generally need specific venting taps, that release a dribble every now and then to relieve pressure. Unvented work with standard taps but may need separate expansion vessel and check valve if connected within a certain distance of cold water draw off point or if expansion cannot be accommodated back down the mains. Unvented may need pressure reducing valve if mains pressure too high. Same may be true of vented - not sure. Anyhoo, we seem to sell a lot of unvented heaters on eBay (we do 10l and 15l) and the manufacturer tells me they are the most popular type. Units up to 15l capacity are not so stringent on installation methods and are capable of DIY fitting if you have basic plumbing skills. Details here, should you care to have a gander: wulfrunenergysolutions | eBay ;-)

 

[One_of_them]

julian above has made very good sense regarding the vented/unvented setup. TBH they are a doddle to install, as above just ensure if the incoming pressure is above the heater manufacturer instructions install a PRV. You can usually just buy the full install kit along with the heater.

I personally use santon where I can, I find ZIP terrible!!!! Depending on you water hardness, I would avoid tanks that have a sacrificial anode internally as these will fail, the tank will rot etc etc. Stick with a known brand so spares are easily available.

Check this PDF and it has some install scenarios which may be of use
http://www.santon.co.uk/docs/Aquaheat_-_Issue_2_-_36005791.pdf

 

[ruston]

If I remember right you can only install up to 15 ltrs unvented , greater capacity you have to be registered.

Just had a quick look-------- Mains Pressure Domestic Hot Water Systems Explained and Compared

 

[One_of_them]

If I remember right you can only install up to 15 ltrs unvented , greater capacity you have to be registered.

Just had a quick look-------- Mains Pressure Domestic Hot Water Systems Explained and Compared

Is that just for gas type though? Like your boiler etc

 

[ruston]

Is that just for gas type though? Like your boiler etc

No , it applies to electric unvented water heaters too. You can download the building reg from the Local government website.


http://www.planningportal.gov.uk/uploads/br/BR_PDF_AD_G_2010_V2.pdf

From page 20 onwards. worth a read if you are not sure.

 

[Darkwood]

Pull a plumber on board ask him to eye the job up and do the neccessary plumbing and you do what your good at.... pay the plumber add a few notes on and charge the customer ...job done quick efficiently and you have peace of mind.

 

[FrankUK]

Unvented (pressurised) water heaters upto 15lts do not come under G3 Building Regulations and do not need a cold water expansion vessel, as the expansion will be taken up in the cold feed pipework.

They do, however, require a means of over pressure relief, which can be a purpose made set of taps (yes they do sell them) or, some heaters come ready fitted with a pressure relief valve, which just needs connecting to a suitable discharge point.

Better still leave the plumbing to the plumbers and just stick to providing the mains power supply, as was pointed out by one member in another thread. http://www.electriciansforums.net/e...-scratcher-lighting-circuit-2.html#post711855