Under sink water heater??

[Ratty]

My father has a small holiday chalet in Somerset. It's got a really old water heater that's very expensive to run and has started leaking. I've been looking at the instant under sink heaters that only heat the water when the tap is on. It's only going to be for the kitchen sink so I've been looking at a 'Dafi' under sink heater, probably 5.5kw. They also do a 3.5kw and 7.3Kw. He's already got a Triton T30i 3Kw in the toilet (well, not actually 'in' the toilet :smile5: ) which doesn't seem 'man' enough for a kitchen sink. I would imagine a 7.3Kw would be a bit of a waste? Have any of you had any experience of Dafi heaters? They seem nice and compact but are they any good?

 

[Reg Man]

No experience with this manufacturer, but probably ok. There are lots of instantaneous water heater manufacturers out there, all use the same technology. Pay your money and take your choice.

 

[Best]

Much more than 3kw is going to need more than just 2.5mm cable, so could mean a rewire.
Remember that your average electric shower needs to be 8.5 kw or more to give a decent flow/hot water & they use 6mm or 10mm cable.

 

[efficiencyman]

If you are going electric it`s not just what`s under the sink. The starting point is power requirements, total loads at consumer unit, think of everything including cooking.
Instantaneous heaters will all way`s have higher loadings than stored vessels.
Are there spare ways in the consumer unit for possible new 10 mm cable ?
A stored water unit may be the better option at only 2 or 3 Kw load.

 

[Dotty]

You won't need much more than a 10 or 15 litre unit, 3kw would be the most you'd require.

One of these will do you. Install it to manufacturers instructions.

MW - 10-15L Unvented Water Storage Heaters | Redring

 

[Ratty]

Thanks for the replies. The electric side of things is no problem. I know I'll need to re-wire but I can sort that out (my job involves MV to EHV) and a mate has got his ticket for checking my work. I'm undecided between the instant and stored heaters. There's currently an old stored wall mounted heater which I want to get rid of. The replacement has to be undersink but low wattage stored or high wattage instant? Stored would have the disadvantage of still heating the water (and running up the bill) if the chalet is empty for a few weeks and he forgets to turn the unit off. Oh well, I'll give it a bit of thought and probably end up tossing a coin to decide!

 

[Marka1411]

I agree with croppie, ideal for what you want it for. At work we fit heatrae sadie products and never have any problems. Fit the 10 and 15 ltr heaters a lot under sinks in schools.

Never fit one of these myself and a model i once talked to a rep about was different to my link but will give you an idea.

Heatrae Sadia

 

[Centralheatking]

Hi Ratty

As well as HVAC we also own a couple of holiday let props in Cornwall - the water is heated by Electricity as there is no nat gas and LPG is dangerous in holiday lets.

If it is just for yourself go down instant hot covered by a time out if left on - if you are letting
then big stored hot water on a timer and boost is the only way as families have instant big demands - back from beach small kids 4x people .........but dont flip a coin make a rational decision and let us know what you decide and report back please ...CHK

 

[Killy Bing]

Hi Ratty

As well as HVAC we also own a couple of holiday let props in Cornwall - the water is heated by Electricity as there is no nat gas and LPG is dangerous in holiday lets.

If it is just for yourself go down instant hot covered by a time out if left on - if you are letting
then big stored hot water on a timer and boost is the only way as families have instant big demands - back from beach small kids 4x people .........but dont flip a coin make a rational decision and let us know what you decide and report back please ...CHK

How many fingers do you have chking?
because you have them in an awful lot of pies!!!!

wheres our discount thread for your services in the arms aye?

 

[Ratty]

If it is just for yourself go down instant hot covered by a time out if left on - if you are letting then big stored hot water on a timer and boost is the only way as families have instant big demands - back from beach small kids 4x people

Now that has given me something to think about. At the moment the chalet is family only but with increasing ground rent etc we are thinking of letting it out to cover some/all the costs. If a family do leave the hot tap running with a 5.5 or 7.3Kw it'll be a lot dearer than a 3Kw storage unit.

 

[anz]

Don't get the Dafi, if your going to go for an instant heater, choose a different one.
I recently installed a 7.3kw version for a customer and the hot water output was really poor.
They're half the price of others, and half the size, so I'm not surprised.

 

[efficiencyman]

Reading opening post again as its only for the sink where presumably the need is to fill quickly with HOT water for washing greasy dishes. Stored HOT will provide that from a 3Kw with reasonable recovery rate.
An instant 8.5 Kw shower OK for kids and teenagers taking consecutive long showers but not rapid enough from the cheaper instant heaters at the sink.
Ask all users to turn off Electrics and Water at mains when leaving.
A prepayment meter should stop things being left switched on.
What is the size of main supply cable to the chalet ?
I have come across a main overloads tripping while cooking & instant shower use Etc.

 

[Centralheatking]

I can let you know about the website we use - if you want to go down this route
it is well presented costs v little and brings us most of our new and returning guests

Let me know CHKing

Now that has given me something to think about. At the moment the chalet is family only but with increasing ground rent etc we are thinking of letting it out to cover some/all the costs. If a family do leave the hot tap running with a 5.5 or 7.3Kw it'll be a lot dearer than a 3Kw storage unit.

 

[Centralheatking]

WE never would install a pre-payment meter in any of our lets - it is naff CHK

Reading opening post again as its only for the sink where presumably the need is to fill quickly with HOT water for washing greasy dishes. Stored HOT will provide that from a 3Kw with reasonable recovery rate.
An instant 8.5 Kw shower OK for kids and teenagers taking consecutive long showers but not rapid enough from the cheaper instant heaters at the sink.
Ask all users to turn off Electrics and Water at mains when leaving.
A prepayment meter should stop things being left switched on.
What is the size of main supply cable to the chalet ?
I have come across a main overloads tripping while cooking & instant shower use Etc.

 

[stevetheplumber]

i would definitely check how much power you have coming in to the chalet most of the ones we've used over the years are pretty low, same with caravans 16 amps isnt unusual

 

[Ratty]

I can let you know about the website we use - if you want to go down this route it is well presented costs v little and brings us most of our new and returning guests

Let me know CHKing

We won't be letting until probably 2015. Got some work to do first to get it up to a lettable standard.

 

[Ratty]

i would definitely check how much power you have coming in to the chalet most of the ones we've used over the years are pretty low, same with caravans 16 amps isnt unusual

Feed isn't a problem. It's not like a caravan park where all the statics are feed from a ring with each having an outside isolator and socket for the small blue 16A plug. It's a standard DNO feed via pole mounted transformers, same as you would find with the houses in your street. From what I remember the incoming feed is fused at 100A between the meter and consumer unit. Consumer unit has 85A switch. It's a direct feed from a Western Power Distribution pole mount transformer next to the chalet - Yup, I'm a bit of a transformer spotter. Comes with my job :-/

 

[Unregistered]

anyone got any ideas why my dafi heaters seem to leak after a while despite being well and truly properly installed - first a 5.5KW and now gone through 2 3.5KW which by the way are not man enough to produce the minimum temperature required of hot water to satisfy the legionalla risk avoidance thingy ma jig, but still, any idea why they leak?

 

[ShaunCorbs]

where are the they leaking from?

 

[PlumbBobBob]

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