Does my Central heating return have to heat hot water cylinder with this set up?

25 Apr 2015
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United Kingdom
Wondering if anyone could comment on the following. Any advice welcome.

I've had a new gas boiler and radiators installed, I decided to keep my unvented cylinder as I like the pressure of shower as is, and I'm still able to heat it electrically if necessary.

My concern is that when the system is running the radiators, will the returning radiator water have to heat up the bottom of the cylinder to the same temperature as the returning water before it stops acting as a load on the boiler? If the answer is yes I'm thinking it might not be a problem anyway? Should there be a one way flow valve before hot water return joins the returning heating water?

The plumber set the control thermostat on the cylinder(between solar in and return) to 48oC ish. But when I felt the lowest pipe in the cylinder in the mornings it felt as hot as the top connection. Is this because the returning heating water could be heating bottom of cylinder above the temp set on thermostat?

Plumber is returning next week to connect open therm to nest heatlink.

Thanks for reading .

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The heat you can feel in the pipe is probably heat conducted by the copper pipe, it looks to have been plumbed in the correct configuration.

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