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John Rumm John Rumm is offline
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Default how hot do you run you CH boiler

On 13/01/2019 03:09, wrote:
On Saturday, 12 January 2019 09:28:26 UTC, Harry Bloomfield wrote:
John Rumm formulated the question :


IME many of the Vaillant boilers do support split temperature
operation, but it does depends on what controls you have them
paired with.

The 400 series Vaillant I did (probably previous model range,
since this was
= 12 years ago), actually had separate knobs on the front for
CH and DHW flow temperatures. Although that was retrofitted
into system with traditional controls that could not
distinguish between the source of the call for heat - hence the
DHW control never came into play and it ran like your system
does.

The blurb on their web site:

https://www.vaillant.co.uk/for-insta...ler-26116.html



Seems to suggest its compatible with the VRC 700 weather compensating
controls, so that ought to allow split temperature as well.


I have studied it and not found any obvious way to split the
temperature. I even spoke to Vailant and they confirmed there was
no way it could be done.


If the Vaillant has 2 separate call for heat signals for DHW & CH it
would be simple enough to split the temp, at least if the boiler has
2 separate temp settings for the 2 circuits, and the Vaillant 400
series I'm familiar with does. Where is the problem happening?


The ecoFit Pure does not appear to have separate inputs:

https://www.vaillant.co.uk/downloads...ual-876622.pdf

However I just found this:

https://www.vaillant.co.uk/downloads...ons-261442.pdf

In its description it says:

"The Control Center VR 65 offers a solution to allow
Vaillant low voltage €˜eBUS controls to be used with the
traditional 230 V zone valves and DHW storage cylinder
in the English market.

Information about the heat required by the cylinder is
forwarded by the Control Center VR 65 to the Vaillant
ecoTEC heating appliance. The boiler then decides
whether a hot water request has to be fulfilled and
sends a signal to position the 230 V zone valves via the
VR 65.

In this way, the boiler can store different target tempera-
tures for heating and warm water operation.
Standard 230 V components can be integrated into the
Vaillant eBUS system via the Control Center VR 65."


also:

"The Control Center VR 65 is an eBUS system compo-
nent.
It is responsible for the communication between the
DHW cylinder, the boiler and external 230 V 2- or 3-port
valves.

Note!
The VR 65 is designed to control one 3-port
valve or two 2-port valves. Systems requiring
more zone valves or a combination of 3-port
and 2-port valves are not possible."


Installation:

"The Control Center can be wall-mounted near to the
DHW cylinder. The hot water and heating programs as
well as all required parameters are set at the VRT 360
or VRC 400. All heating circuit connections are made at
the Control Center using a ProE plug"

of the VR360 it says:

"VRT 360
Digital room temperature thermostat with daily/weekly
program for time and temperature control of heating
and hot water.
Designed for wall mounting.
There are three individually programmable time win-
dows per day for heating, hot water and a hot water
circulation pump. Different target room temperatures
can be set for each time window.
The thermostat can be set to run a weekly or a daily
program.
By activating the calendar function, an automatic
summer/winter changeover is activated."

Which sounds like you may be able to do:

VRT360 + VR65, conventional 3 port valve, and conventional cylinder
stat. No need to go fully weather comp.


--
Cheers,

John.

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