Run back switch on undersink heater

coL

I am thinking of fitting an undersink water heater (atlantic 10l) and I am just wondering what options I might have for putting a timer/switch on it so that it switches off after 10-12 minutes (rather than have an on/off schedule)?

For my initial research it seems like a run back timer is exactly what I need. Has anybody had any experience of fitting one of these in a situation like this or any advice/guidance/feedback in general?

I am being told by the plumber and his electrician that it will be fitted with a standard three pin plug that can go in to a normal socket as all it is really is a glorified kettle (it will be properly vented). Not being familiar with the regulations around this I just wanted to check if this way of installing it sounded right to everybody?

Thanks in advance

2011

coL wrote: »

I am being told by the plumber and his electrician that it will be fitted with a standard three pin plug that can go in to a normal socket as all it is really is a glorified kettle (it will be properly vented). Not being familiar with the regulations around this I just wanted to check if this way of installing it sounded right to everybody?

This is a lazy solution, I would not be happy with this. It should be permanently wired (not a plug / socket) and it would be far better if controlled by a suitable timer.

coL

2011 wrote: »

This is a lazy solution, I would not be happy with this. It should be permanently wired (not a plug / socket) and it would be far better if controlled by a suitable timer.

I take your point but it's a retrofit so certain compromises have to be made. A permanently wired solution would be the preference but would it require a different circuit and a similar set up to an immersion or could the power still be taken from the socket circuit? Ultimately they will do whatever I ask but if its not specifically required by regulations then I could be paying a lot for no real reason and have to weight up convenience vs cost.

We actually don't want a timer fitted as we would prefer to be in control (albeit with a 12 minute lead time) of when we want to hot water rather than have something heating up on a set schedule when we might or might not need it.

Current plan is for just an on/off switch but the fear with that is that we will keep forgetting to turn it off. There is a thermostat on the heater that will regulate the temp but we don't want it on when we don't need it.

Sleeper12

I'm not an electrician but doesn't this require the same protection as the immersion in the hot press?

2011

coL wrote: »

I take your point but it's a retrofit so certain compromises have to be made.

Why do you say this? No compromises need to be made.

A permanently wired solution would be the preference but would it require a different circuit

Not likely.

Ultimately they will do whatever I ask but if its not specifically required by regulations then I could be paying a lot for no real reason and have to weight up convenience vs cost.

I just feel that a plug in solution is a gunter. My attitude is that your home is most likely to be your most valuable asset so don’t cut corners.

We actually don't want a timer fitted as we would prefer to be in control (albeit with a 12 minute lead time)

So you do want a timer, one that counts down 12 minutes.

coL

Currently we have a double socket under the sink that the dishwasher is plugged into but beyond that there is no power going to this location. If it complies with regulations a three pin plug onto the water heater is the easiest and cheapest solution. It may seem lazy but if its compliant with regs why is that necessarily a bad thing especially if the alternative will cost a lot more for the same end result? If a plug works and is safe I don't see it as cutting a corner.

This is not a new build so I obviously can't do it in the same way I would if I didn't have to worry about the existing kitchen/wiring and how it will all integrate, hence the compromise. @2011 When you say no compromise is necessary what do you mean and what would your preferred solution be in this scenario?

If the water heater can be permanently wired from the socket circuit then it's the ideal solution, especially if I can but some kind of timer on it. If it can't then all other options involve a time and money cost which I need to consider with respect to the existing kitchen. I am trying to figure out what the regs/best practise require and how I can achieve this. How do I find out for definite what power source is required for the water heater and if it can be powered from the socket circuit?

We want a countdown/run back timer that will shut itself off after a set amount of time from when we press the button rather than a timer that is set to turn on/off at various times of the day regardless of requirements.

2011

coL wrote: »

@2011 When you say no compromise is necessary what do you mean and what would your preferred solution be in this scenario?

Subject to a survey: I would supply the water heater from a spur outlet. This spur would be fed from the socket that the dishwasher uses.

Next I would install a timer that when pressed would switch the heater on for the required time (I have seen 15 minute timers like this). It is generally possible to neatly wire this above the counter top to a suitable location.

How do I find out for definite what power source is required for the water heater and if it can be powered from the socket circuit?

Get a good registered electrical contractor to look at it and advise.

coL

2011 wrote: »

Subject to a survey: I would supply the water heater from a spur outlet. This spur would be fed from the socket that the dishwasher uses.

Next I would install a timer that when pressed would switch the heater on for the required time (I have seen 15 minute timers like this). It is generally possible to neatly wire this above the counter top to a suitable location.



Get a good registered electrical contractor to look at it and advise.

That is exactly the solution I was hoping to put in place but I wasn't sure if a spur could come off the socket for the water heater.


There is a silestone splashback around the full countertop so bringing up a switch is problematic and might not look that great, would be happy to have it in the press beside the heater.


The electrician I am using is RECI qualified and he is the guy that is telling me a plug is fine. Like I said I am sure he will do it if I ask but I want to make sure what I am asking him to do is possible before I force the issue.

I have seen the type of timer I want online (link below) and was hoping to get feedback from anyone that might have used them.

http://www.prefectcontrols.com/our-products/run-timers/pre9270/

Tuco88

I take it those Atlantic heaters are around 2kw?
You could look at some of the heating/Immersion boost timers also. Once the current rating is ok.

Its typical to see this done hard wired, with a switched spur outlet with suitable fuse. As stated above.

So you know it will take a bit of time to heat up? Not so sure how efficient it will work in this setup tho.

coL

Tuco88 wrote: »

I take it those Atlantic heaters are around 2kw?
You could look at some of the heating/Immersion boost timers also. Once the current rating is ok.

Its typical to see this done hard wired, with a switched spur outlet with suitable fuse. As stated above.

So you know it will take a bit of time to heat up? Not so sure how efficient it will work in this setup tho.

I need to see the specs to be sure but I think it’s around 2kw alright.

A friend has one and it takes around 10-15 mins to heat the 10l. We want something that switches off after a set time. Can you get programmable boost timers that can be set for this long or do they all boost for an hour?

Tuco88

coL wrote: »

I need to see the specs to be sure but I think it’s around 2kw alright.

A friend has one and it takes around 10-15 mins to heat the 10l. We want something that switches off after a set time. Can you get programmable boost timers that can be set for this long or do they all boost for an hour?

Unless you go for normal timer and select typical expected times eg 8:00AM so on...

No they have the same times as the one you have linked. Only have leds and a button per time so on...

Eric Cartman

Normal sockets aren't supposed to be in those parts of the bathroom as they're not IP rated correctly .

You can have a fused spur timer.

Most people just leave those heaters on all the time, it heats 10 litres and leaves it there for use at any time, no idea why you'd bother.

coL

Eric Cartman wrote: »

Normal sockets aren't supposed to be in those parts of the bathroom as they're not IP rated correctly .

You can have a fused spur timer.

Most people just leave those heaters on all the time, it heats 10 litres and leaves it there for use at any time, no idea why you'd bother.

It’s not for a bathroom it’s for the kitchen.

Don’t know anybody that leaves their water heater on full time and I certainly don’t want to pay for 10l of water to be kept hot 24hours a day. Only reason I want some type of timer is so we don’t forget to switch it off and can avoid exactly this type of situation.

xl500

coL wrote: »

It’s not for a bathroom it’s for the kitchen.

Don’t know anybody that leaves their water heater on full time and I certainly don’t want to pay for 10l of water to be kept hot 24hours a day. Only reason I want some type of timer is so we don’t forget to switch it off and can avoid exactly this type of situation.

I have been using one of these for years under kitchen sink brilliant to have hot water on demand I leave mine on all the time as they are so well insulated you are only paying for small loss unless someone draws water you will probably find the difference between making up small heat loss or letting go cold and waiting 15 mins for it to heat will be very little but for me the whole idea is to have hot water immediately I turn hot tap and if it's under kitchen sink you will be turning it on off lots of times during day depending on family size and waiting for it to heat I leave on and forget about it

2011

^^^^ I have seen this too. I these units are not that common but I think this is the way are designed to be used.

coL

xl500 wrote: »

I have been using one of these for years under kitchen sink brilliant to have hot water on demand I leave mine on all the time as they are so well insulated you are only paying for small loss unless someone draws water you will probably find the difference between making up small heat loss or letting go cold and waiting 15 mins for it to heat will be very little but for me the whole idea is to have hot water immediately I turn hot tap and if it's under kitchen sink you will be turning it on off lots of times during day depending on family size and waiting for it to heat I leave on and forget about it

I have seen them used like this too but we only need hot water once or twice a day and even then don't need it every day. We usually don't need it immediately, just to wash pots and pans that won't fit in the dishwasher so we can afford to wait 10-15 mins for it to heat up.

The cost of keeping it on might be small but its also an unnecessary cost that doesn't need to be incurred (it also seems a little bit wasteful). We would prefer to heat and use it as needed and are happy to switch it on and off as required. If we can get a run back timer that will switch off automatically then it makes everything easier.

xl500

coL wrote: »

I have seen them used like this too but we only need hot water once or twice a day and even then don't need it every day. We usually don't need it immediately, just to wash pots and pans that won't fit in the dishwasher so we can afford to wait 10-15 mins for it to heat up.

The cost of keeping it on might be small but its also an unnecessary cost that doesn't need to be incurred (it also seems a little bit wasteful). We would prefer to heat and use it as needed and are happy to switch it on and off as required. If we can get a run back timer that will switch off automatically then it makes everything easier.

Fair Enough whatever suits you

Eric Cartman

A Horstmann E15 timer switch and a fused spur is what you want op.

2011

^^ exactly

coL

Eric Cartman wrote: »

A Horstmann E15 timer switch and a fused spur is what you want op.

That is exactly what I am looking for, thanks.



Someone elsewhere has also suggested using a lag switch similar to the ones used for lighting but my understanding is that (the ones I am familiar with anyway) are only rated to 300w so can't be used for a water heater?

2011

coL wrote: »

That is exactly what I am looking for, thanks.



Someone elsewhere has also suggested using a lag switch similar to the ones used for lighting but my understanding is that (the ones I am familiar with anyway) are only rated to 300w so can't be used for a water heater?

Apart from possible rating issues I don’t think any would have a lag time as long as 15 minutes.

Sleeper12

I know that you said that it would be properly vented but usually these units will need an expansion vessel & a pressure release device. Many plumbers don't realise this as they fit so few of them. No vessel & no pressure release device = a bomb. Some have a vessel inside but you need to be 100 percent certain & double check what the plumber is doing. As I say many plumbers don't realise what is required.

I'm on my phone now and can't link but there is a plumbing thread (I think by Gary the gas man) about the dangers of these not being installed correctly

coL

2011 wrote: »

Apart from possible rating issues I don’t think any would have a lag time as long as 15 minutes.

I have seen one that is adjustable and can go up as far as 12 minutes. It has three different wattage settings but the highest one is only 300w which is well short of what I need.

I know that you said that it would be properly vented but usually these units will need an expansion vessel & a pressure release device. Many plumbers don't realise this as they fit so few of them. No vessel & no pressure release device = a bomb. Some have a vessel inside but you need to be 100 percent certain & double check what the plumber is doing. As I say many plumbers don't realise what is required.

I'm on my phone now and can't link but there is a plumbing thread (I think by Gary the gas man) about the dangers of these not being installed correctly

Thanks for the info but the plumber assures me that the one we are going to install will have a suitable pressure release valve.

Sleeper12

coL wrote:

Thanks for the info but the plumber assures me that the one we are going to install will have a suitable pressure release valve.

It requires an expansion vessel too though. If there isn't an internal vessel he needs a add one.

EDIT: I found the link on the dangers of not installing correctly

https://www.boards.ie/vbulletin/showthread.php?p=93898510

coL

Sleeper12 wrote: »

It requires an expansion vessel too though. If there isn't an internal vessel he needs a add one.

I will check with him

Eric Cartman

coL wrote: »

That is exactly what I am looking for, thanks.



Someone elsewhere has also suggested using a lag switch similar to the ones used for lighting but my understanding is that (the ones I am familiar with anyway) are only rated to 300w so can't be used for a water heater?

Heater will be 2000w , most of these are designed for lighting and will be <400w , the horstmann is what you want.

On the expansion vessel , there are some compact options or special taps that act as a pressure release but those are a bit mad money, if its in a press and hidden the expansion vessel is the cheapest option.

If wiring allows op you could go with a completely tankless solution like this

https://www.ie.screwfix.com/redring-powerstream-eco-bathroom-water-heater-9-5kw.html?utm_source=Google&utm_medium=CPC&utm_campaign=Shopping&gclid=EAIaIQobChMIh9Or4Obe3QIVLrXtCh1uWQCBEAQYCSABEgJX5PD_BwE&gclsrc=aw.ds

It will only consume power while making hot water instantly