Undersink water heater

murphy_j

Hi all

Let me start with a rant about plumbers that promise to turn up and then dont...or those that turn up and find the job is too small and walk away...why cant I find decent plumbers in laois...anyway...

Our kitchen sink is at the end of a long run for hot water and the result is that it doesnt get any hot water. The installation was messed up by the plumber during a refit 4 years ago so ive decided that we need to install an under sink heating unit but as alluded to above I cant get a plumber interested to do it for me.

My belief is that I can get an Ariston unit that takes a mains cold feed into the top and a hot outlet straight to the taps. I have a mains connection going to an outside tap that I can use or would I be better using the connection from the attic that gives me 'softened' water? Size wise I have space beside a water softner. Im guessing that it needs to be on its own circuit (2K will not be a great idea coming from the dishwasher outlet?).

Has anyone installed one of these? Id appreciate any tips or potential pitfalls before I go ahead and try it.

Thanks

ttm

murphy_j wrote: »

Our kitchen sink is at the end of a long run for hot water and the result is that it doesnt get any hot water. The installation was messed up by the plumber during a refit 4 years ago so ive decided that we need to install an under sink heating unit but as alluded to above I cant get a plumber interested to do it for me.

Just interested to know why the kitchen doesn't get hot water? If you leave the tap on doesn't it eventually come out at least warm - obviously provided there is hot water in the tank?

Provided it does come out hot eventually I have seen solutions on older houses where a second pipe was taken back to the h/w tank from near the kitchen tap and a pump put in this loop which swtiched on by a pressure switch (or timer sometimes) pumping water around the loop, so the hot water came through quicker, the loop means hot water is kept in the pipe and stops any problems from over pressure fromthe pump.

10-10-20

True - you can do this but it's very wasteful.
The loss in the pipe can be very large as the old pipe may not be insulated perperly. Also, the additional costs for the pump power is a factor.

northdublin

i think there are two types of undersink water heater. the first has a sizable tank that heats and stores the water untill its ready to be used. the other type heats the water trough an element similar to an electric shower. the first type is more usefull in domestic situations and the later is really only for having hot water on tap for washing your hands and stuff like that. the type with the tank is usually bigger and has an inlet and an outlet either on top or underneath the unit depending on the installation. i think a standard undersink heater is about 140 euro plus vat.

bushy...

The tankless/instantaneous ones would be better surely ?
you are only heating just the amount you need
no waiting for the tank to warm up
"unlimited" hot water

311

bushy... wrote: »

The tankless/instantaneous ones would be better surely ?
you are only heating just the amount you need
no waiting for the tank to warm up
"unlimited" hot water

The standard undersink heater has a thermostat, it wouldn't be on all the time.
I'd prefer the standard one over the instantaneous ,because it's less hassle to install and in my mind safer aswell.

northdublin

would i be correct to say that the instantanious type would use more power and cost more to run? also the instantanious type even though smaller are usually mounted over the sink with a little nozzle extending over the sink. the undersink type are quite large and would take up about half of the space of a standard under sink cabenit.

murphy_j

Thanks guys

btw - we do eventually get hot water but it has to runthrough 1/2" pipe for about 120 feet and then 1/4" for another 20 before it hits the kitchen.

The one with the little tank underneath might be ideal - does anyone know if this does needs a mains (electrical ) connection or is it a plug into a socket kind of thing?

Also, softened or mains water preferred?

311

The undersink units are different sizes ,they work much the same as a hot water immersion and cylinder. A timer powering the unit ,might be a good way to keep costs down.

I'm a plumber and not a sparks ,so I can't advise on wiring

northdublin

with regard to the elctrics a fused spur off a socket will do the trick. if in doubt ask a sparks or post a question in the electrical section.

10-10-20

Northdublin - correct to a point! Some of these units are greater than 3000Kw and shouldn't be connected to the standard ring.

bushy...

northdublin wrote: »

the instantanious type even though smaller are usually mounted over the sink with a little nozzle extending over the sink. the undersink type are quite large and would take up about half of the space of a standard under sink cabenit.

This type of instantaneous heater goes inline in the hot water pipe same as the tanked one.

http://www.acehardware.com/sm-bosch-powerstream-tankless-instantaneous-electric-water-heater-bosch-powerstream-tankless--pi-1442468.html

Alun

10-10-20 wrote: »

Northdublin - correct to a point! Some of these units are greater than 3000Kw and shouldn't be connected to the standard ring.

Indeed ... 3MW would be a bit much for an average house supply :D

frankie2shoes

slap electric water heater into ebay and you'll get a couple of fairly neat inline instantaneous water heaters. I have a similar problem with a long run to bathroom- water takes an age to reach the taps.
I would imagine that the electric water heater would have to be installed in a similar fashion electrically as a power shower ie with its own isolated supply.
anybody know how expensive these heaters are to run?

If you go with the under sink heater have it fitted to UK regs, which you can find with this link http://www.ariston.co.uk/uploads/doc47be9f9c70766.pdf,
if it's fitted to Irish standards you risk flooding:(, the UK regs have a discharge pipe to outside and water expansion must be factored in, which makes for a better instillation, Gary.

irishpaddy

murphy_j wrote: »

Hi all

Let me start with a rant about plumbers that promise to turn up and then dont...or those that turn up and find the job is too small and walk away...why cant I find decent plumbers in laois...anyway...

Our kitchen sink is at the end of a long run for hot water and the result is that it doesnt get any hot water. The installation was messed up by the plumber during a refit 4 years ago so ive decided that we need to install an under sink heating unit but as alluded to above I cant get a plumber interested to do it for me.

My belief is that I can get an Ariston unit that takes a mains cold feed into the top and a hot outlet straight to the taps. I have a mains connection going to an outside tap that I can use or would I be better using the connection from the attic that gives me 'softened' water? Size wise I have space beside a water softner. Im guessing that it needs to be on its own circuit (2K will not be a great idea coming from the dishwasher outlet?).

Has anyone installed one of these? Id appreciate any tips or potential pitfalls before I go ahead and try it.

Thanks

hello i know its a long time since you posted but i am looking for an under sink water heater. the reason i want it is i have had my hot water tank disconnected from my system, we don't use it for baths or anything like that. but having it disconnected is my radiatiors get hot much quicker and it saves having to heat the tank every time the heating comes on. but could you let me know if you got it sorted;; and by the way, ****ing plumbers, i have one fair play to him if it is serious he turns up really quick, but if it is just something for my comfort he can take a year. ah well you think it would be easy to get one now but it seems they have all left for austrialia. if my spelling is all over the pleace it's because i cant find my spell check.

sullzz

irishpaddy wrote: »

hello i know its a long time since you posted but i am looking for an under sink water heater. the reason i want it is i have had my hot water tank disconnected from my system, we don't use it for baths or anything like that. but having it disconnected is my radiatiors get hot much quicker and it saves having to heat the tank every time the heating comes on. but could you let me know if you got it sorted;; and by the way, ****ing plumbers, i have one fair play to him if it is serious he turns up really quick, but if it is just something for my comfort he can take a year. ah well you think it would be easy to get one now but it seems they have all left for austrialia. if my spelling is all over the pleace it's because i cant find my spell check.

You can get an undersink water heater , in any plumbing providers , I generally use the ariston brand as they are smaller in size than the other ones available with the same capacity , under sink ones are generally 10 litre .
If getting it fitted I would get the installer to fit an expansion vessell , and a safety valve pipes to outside and a pressure reducing valve if required , depending on your mains pressure , the reason I mention this to you is as its never really done .
Bear in mind that you will loose the best part of a kitchen unit .

mp22

Just to let you know most under sink heaters have a sacrificial anode fitted,this must be changed every couple of years.

sullzz

mp22 wrote: »

Just to let you know most under sink heaters have a sacrificial anode fitted,this must be changed every couple of years.

What type are you on about , the ones im on about are sealed units

eddieham

Here are two of the more popular models in Ireland both of which have the sacrificial anode

http://www.rtlarge.ie/wp-content/themes/swatch/pdfs/2012-2nd-run/webcat-102.pdf

http://www.atc.ie/heating_ventilation/documents/ATCZ-IOU10LUnderSinkWaterHeater.pdf

Both available from must plumbers merchants or electrical wholesalers

sullzz

I could be wrong but I dont think that aristons 10l undersink have anodes fitted , I know that their cylinders do

eddieham

first link I gave is for ariston and it gives details within of the anode

"Heaters containing a magnesium anode must be serviced every 12
months."

Taken from ariston link above

Have just checked here also and on page 10 it says that 10l models do have

http://www.ariston.com/uk/media/files/458_EP%20R%20Manual.pdf

sullzz

I stand corrected , thanks for the link !!!

The anode has to be checked every year but only replaced when nesseary, the Crome safety valve should never be fitted in line with the cold supply it should fitted with a tee piece leaving the cold side open for expansion, the safety valve is rated at 8/9 bar and a 6 bar is better, the discharge should go in to. Hep2o trap before the waste.

I would advise anybody fitting these heaters to please read the UK water regs, these heaters are pressurising water and can be dangerious, i'v commonly seen heaters fitted in schools and creshs that are a risk to the small people who are using them, sadly.

JHeff101

Hi does anyone have a working link to the Irish regulation that deal with installing undersink water heaters?

It would be very much appreciated!

perry stanley

The regs are mostly a reprint of the uk ones

JHeff101

JHeff101 wrote: »

Hi does anyone have a working link to the Irish regulation that deal with installing undersink water heaters?

It would be very much appreciated!

There are no regs.

UK regs are usually used by insurance company's as a bench mark when investigating a claim.