How to add a DAFI instant water heater with pipe thermostat to a gas boiler system?

Hello,

I live in an old detached house with central heating, and the bathroom is heated by a gas boiler (condensing).
Unfortunately, the kitchen is quite a distance from the boiler (which is in the loft), so it takes over a minute for hot water to come out of the tap; for short uses, the hot water doesn’t even reach the tap.
I would like to install an electric instantaneous water heater (e.g. DAFI) on the hot water pipe from the gas boiler. I would like to install a THERMOSTATIC SWITCH on the hot water pipe before the electric water heater (at a suitable distance) so that a relay automatically switches off the heater when the hot water from the boiler ‘reaches’ the kitchen plumbing (i.e. the inlet to the heater). I’ve looked for such a switch but without success (preferably one that can be fitted onto the pipe without the need for ‘penetration’ – please could you offer some suggestions? (Apologies for the lack of Polish characters – I’m using the English version of Windows)

Best regards!

Polish letters are on the left-hand side, under the engineering symbols. Please correct the spelling in your posts! [retrofood]

http://czesciagd.pl/termostat-bojlera-typ-kt165-avb-0454-p-201757.html

Thanks, Pletwa, but I’m looking for something more specifically designed for installation on a pipe, or with a block so I can connect it to the pipes ‘in-line’.

Is the tube made of metal? So what’s the problem? You attach the capillary tube to the pipe, tuck the rest away into an airtight casing, install it somewhere convenient and out of sight, set it to 40°C and don’t look at it again.

But if that’s what you want.

All in all, it’s a good idea. Do you know what sort of load I can put on this switch? I’m thinking of using a 3.7 kW heater.

Unfortunately, the maximum contact rating isn’t specified anywhere. I use two of these to control my central heating boiler and, as far as I can remember, the maximum is 10A. You need at least 16A, so, as you mentioned above, you’ll need to use a suitable contactor.

Here’s a 16 A terminal block Link It’s just that the load is almost at its limit. 3680 W.

Unless you’re thinking of a tap-mounted heater, all those with water temperature control have a built-in sensor. In other words, if you supply hot water from the boiler to the heater, it simply won’t switch on.
It’s a question of choosing the right heater.