What capacity water heater do we need?

[funkeii]

Hi guys! We have installed two small sinks in our shop - one for handwash and one for salad wash. I need to provide hot water to them (they use a shared mixer tap which is central over both sinks).

I would like an under sink instantaneous hot water heater installing, but not sure on what Kw or litre capacity to get?

I have been told by the landlord's 'plumber' that it won't need a pressure reducing kit or pressure relief valve - but wondered how I can check if this is correct?

I am in Doncaster town centre so not sure about water pressure or hardness or if this is something I need to consider?

I am not that sure if I need a vented /unvented system to be honest! So any help is appreciated!

Will I need to get the install signed off for building regs or is that only for ones above 15 litres? I am not a plumber be any means just a new start up business owner!

But I would be grateful of any advice about what I should be looking for or if anyone can recommend a decent set up?

Thanks in advance! Kath :winkiss:

(p.s sorry if this is all in one paragraph - my 'enter' doesn't seem to be working! lol)

 

[chris watkins]

How often will the hot water be used & around how much water each time? It is all about storage & recovery !!

 

[Dotty]

Edited your post for you, and welcome to the forums.

What capacity are the sinks? For what you're after a 15ltr unvented would possibly suit. But it will need a safety valve and possibly a pressure reducing set (valve and expansion vessel)

Unvented vessels of all sizes need to be installed by a G3 qualified plumber who will advise you best on your incoming pressure.

Don't let the landlords have-a-go hero anywhere near it. Best use for him is as a door stop or a shelf!

 

[funkeii]

Thanks Croppie & Chris, it will be little volume but often through the day being a deli, but I think a 5Kw would suffice for this? I have been looking at the Ariston one in Screwfix? I will get someone qualified out to look at it, but wondered as my electrician is here this week, could he fit the electrical side now - eg 20amp switch and socket ready for it? Or is it best to wait? cheers again!:winkiss: (Sorry again for no spacing in my text - not sure what's happening??!!!)

 

[Dotty]

Can't find a 5kw one there Kath. But then I wouldn't advise you to supply the heater.

If you get an unvented guy in, tell him what you want and he'll advise you of what's best.

He'll supply and fit it plus he'll be responsible for the warranty for you. Whereas if you supply it he's only responsible for his work!

 

[marvoni]

5kW is more than 20 Amps. An instantaneous heater will most likely require its own circuit and it shouldn't need a socket unless the manufacturers specify one. I'd get a sparky to do a survey if I were you, there's always more than one way to skin a cat and a lot of it depends on your existing installation.

Get the electrical survey done before you purchase your heaters, you may need 3-phase heaters depending on your existing setup.

 

[chris watkins]

You can still get the vented units this would have the advantage that it can be run off of a 13amp standard supply & would not require a safety valve discharge pipe to outside but it would mean that you would have to replace the taps with a special vented set. These storage units will always outlast & out perform an instantaneous. Either way that is why you should employ a professional who can run through all the options & hi-light the pro's & con's.
http://www.heatraesadia.com/docs/UTC-Issue_1.pdf

 

[Dotty]

5kW is more than 20 Amps. An instantaneous heater will most likely require its own circuit and it shouldn't need a socket unless the manufacturers specify one. I'd get a sparky to do a survey if I were you, there's always more than one way to skin a cat and a lot of it depends on your existing installation.

Get the electrical survey done before you purchase your heaters, you may need 3-phase heaters depending on your existing setup.

Hmmmmm. Agree with the survey and a dedicated supply but a 15ltr UV heater is only 2-3kw. 3 phase would be overkill and wouldn't be available in the shope anyway Marv.

I'll pm you a few threads you might enjoy in a minute mate!

 

[marvoni]

Looking forward to the PM

Even with 5kW mentioned by the op it may need to be 3-phase if they have a 3-phase supply and there's not 25A to spare on any one single phase. The same heater in 3-phase+N would draw 6A (ish) per phase.

We also spec 3-phase option for heaters to keep the load balanced if the premises has a 3-phase supply but it all very much depends on the existing supply and installation.

 

[dancinplumba]

15 Lt invented 2kw is ideal IMO agree with croppie

 

[funkeii]

A fountain of knowledge as ever! Many thanks everyone! I shall get someone asap to come and have a look then - I may even ask on here if I may? Thanks guys for all your help - even though I am no plumber, I do like to be informed about what I have installed etc in my business and this forum never lets me down, so thanks guys! The electrics are not 3 phase - but we are installing a new 17 way high integrity board and I would have thought the water heater supply would be on it's own RCBO for the - that's what my electrician has suggested. I have looked at heaters on various websites including plumbco, screwfix, ebay etc and brands I've seen are - hyco, daafi (polish I believe), ariston, redring, ascot,......the list is endless! I just don't know if it is vented or unvented I would require?.....Anyway thanks again everyone! (Now...how do I fix this bloody 'enter' button to stop me from looking like a prat who can't type!? lol):44:

 

[marvoni]

The electrics are not 3 phase - but we are installing a new 17 way high integrity board and I would have thought the water heater supply would be on it's own RCBO for the - that's what my electrician has suggested.

Sounds like good advice. If your supply is single phase then ignore my 3-phase advice above.

(Now...how do I fix this bloody 'enter' button to stop me from looking like a prat who can't type!? lol):44:

The enter problem was caused by a buggy Internet Explorer update. You could try using a real-mans (or womens) browser until they fix it .

 

[funkeii]

Lol thanks Marvoni! Consider a 'real woman's' browser immediately being installed as I (badly) type! thanks for that :winkiss:

 

[Dotty]

Sounds like good advice. If your supply is single phase then ignore my 3-phase advice above.


The enter problem was caused by a buggy Internet Explorer update. You could try using a real-mans (or womens) browser until they fix it .

Hmmmm. Dan didn't tell us about the ie issue!

I like it when mods from t'other forums drop in!

I must pop over your sometime!

 

[marvoni]

Not sure if it's official about the IE update it's just everyone who's had the 'enter' problem seems to be using IE and it doesn't carry across other browsers if they try Opera or Chrome.You're aways welcome on the other forum, let me know in advance if you're coming over and I'll get a couple of six-packs and hide them in the back of the fridge for you