water heat

This is what you want:

On 23/07/12 14:58, Dennis wrote: >

Thanks for that. Interesting, but I'm not sure it's really what I want, because there still wouldn't be any hot water available for some time. In my case it's about 30 seconds in this weather. It'd be good for saving water though.

I'd prefer the "luxury" of instant hot water. A separate, automatic switching heater, rather than a pump, could provide this. I don't think the extra power needed for short term heating would be excessive.

I wonder if anyone sells these?

yeah, any of those on-demand heaters would do the trick, they all have thermostats.

you may need to have the house supply upgraded to 2 phase though.

Maybe the hot water unit for a shower - it probably has its own built in thermostat if the water exceeds a certain temperature.

I know someone who had this problem in their kitchen. They installed a small electric hot water on demand unit under the sink, fed from the main HW system. Worked just fine.

These guys have one:

Several power ranges: 2.4kW to 9.6kW, the higher wattage units would probably require upgrading the mains wiring.

It's meant to be fed with cold water so you'd have to check if it stops heating once the incoming water warmed up, or conversely if it has a limit to the output temperature (which is quite likely in these days of safety consciousness).

HTH Chris.

As a guess, his curren tank is off peak and the heater would have to be on standard power. Might just need an extra circuit solely for the instant heater.

"Jordan"

The electrical power requirements for such a heater ( about 6 kW ) is prohibitive, not to mention the high cost.

.... Phil

Could be.

Could be. Main heater is gas instantaneous.

Know what make, model?

Worth checking, thanks.

Thanks.

Please explain.

Calcs?

specific heat of water times flow rate times temperature difference needed to be heated you can look the fist value up, the other two will need to be measured

"swanny"

The low capacity unit supplies hot water for only a few minutes, then when it would otherwise run cold - it simply does not as the in-coming water is already H O T hot !!

A plug-in, 2kW rated, 10 litre unit would be fine.

I wonder if it is 100% legal under plumbing rules......

.... Phil

I'd sugest the "lagging" trick first. clack rubber has tubes you can split and cable tie around the pipes to slow down the thermal loss.

It was suggested and installed by a very reliable plumber. It's only about 10 litres and plugs in to a GPO next to the dishwasher.