Instant hot water

[RickyLee53]

Hello,

I have looked at any ways to get instant hot water in my kitchen.

We have a long run from the unvented cylinders, some of which is large bore pipes 22mm. So to DHW in sink or basin in the downstairs toilet takes 30 seconds to be warm.

I have one of these at work, it works great. However if we all wash or hands or try to after the sink has been used it runs cold.

http://www.screwfix.com/p/ariston-europrisma-2kw-10litre-usink-water-heater/75532

Could I pipe hot water into this unit? Rather than cold, therefore it would give instant heat that doesn't run out. I can't see any reason why it wouldn't work. I'm just wondering about the legalities of doing so.

It is my own home.

Regards
Ricky

 

[Agile]

Its not expected but I dont see why not.

But you will still have a slug of cold water entering from the pipe.

Have you thought of just insulating the existing hot water pipe?

Using a 15 mm supply pipe will reduce the amount of cold water before hot.

Tony

 

[RickyLee53]

Its not expected but I dont see why not.

But you will still have a slug of cold water entering from the pipe.

Have you thought of just insulating the existing hot water pipe?

Using a 15 mm supply pipe will reduce the amount of cold water before hot.

Tony

Hello,

I think I have thought of everything. haha.

The issue is all the pipes take the same route. This is a slight advantage at times but a disadvantage at others.

I.e. The bath/shower everything goes through 1 22mm pipe. When the bath has been run the water stays warm and warms up quicker downstairs. Because the first 10 meters of 22mm have been filled.

I also thought about a "ring main" but the added pipes/cost and hassle didn't seem worth it.

The kitchen has the sink on an island. Which is 10meters on its own away from the edge where the pipes drop down the wall. This run is 15mm. Insulated etc but the water doesn't stay warm for long.

I have thought about the cold water entering the tank. But obviously it would mix with the hot. So it would never drop ice cold. Then it would increase in temperature again.

I also considered another unvented cylinder in a kitchen unit at 90l. But again/cost hassle is high.

 

[Agile]

It should be cheaper to run a new 15 mm plastic pipoe and add a circulating pump so you get instant hot water at the kitchen.

Thats likely to be cheaper than your 10 li tank !

I dont think you are correct about the tank having cold water entering. I would expect it to go pretty cold. They dont give a continual flow, just reheat every 10 minutes.

Tony

 

[RickyLee53]

It should be cheaper to run a new 15 mm plastic pipoe and add a circulating pump so you get instant hot water at the kitchen.

Thats likely to be cheaper than your 10 li tank !

I dont think you are correct about the tank having cold water entering. I would expect it to go pretty cold. They dont give a continual flow, just reheat every 10 minutes.

Tony

It isn't now as the 15mm is buried under concrete. I "could" chase another pipe in I guess however, i read you couldn't have a return loop in plastic? Is this correct? I can't see why, as you can run it on heating without issue.

A pump to circulate is also going to cost though.

I suppose, the way i've done the plumbing if I did do it that way, all the taps would have instant hot water.

More to think about.

I'm about to buy another of the same heaters for a toilet at work. I might test fit it at home to see how it works.

Thanks for your help.