Hi

Well the subject says most of it really I currently have a 2 zone
(CH & HW) Y Plan system and am looking for electrical circuit layouts
to extend this into a 3 zone system (CH, HW & Heat Exchanger for
swimming pool).

I am looking to keep the existing mid position valve, and add another
mid position valve in the 'feed' to the existing mid position valve.
Now I know that makes my electrics more complicated, as I can't go to
a relatively simple 'S Plan Plus' system, but it make my plumbing a
lot easier.

Whilst I would like to go to a 'fully functioning' system with all 3
zones and combinations of those zones available, a simpler circuit
that simply turned on swimming pool pump, boiler and mid position
valve to 'Heat Exchanger only), at the expense of ignoring any demand
from the CH or HW systems would be fine.

I have spent some time searching this group and google, finding the
odd comment about 'it gets complicated', but never finding answers.
With the number of people installing swimming pools, and the number of
Y plan systems out there - many people must have done this before?

Thanks in advance
Kevin

On 6 Apr, 09:51, wrote:

Whilst I would like to go to a 'fully functioning' system with all 3
zones and combinations of those zones available, a simpler circuit
that simply turned on swimming pool pump, boiler and mid position
valve to 'Heat Exchanger only), at the expense of ignoring any demand
from the CH or HW systems would be fine.

Thinking about this simpler option, I have a plan which I think is ok.

Take a feed from the mains isolator switch that currently supplies the
boiler electrics, first through a time switch (the same as is done for
the CH time switch and HW time switch currently), secondly through a
thermostat for pool temperature control, then into a new wiring centre
to make it easy to feed from this point the following 3 connections:
1) to the new mid position valve, requesting it goes to 'A
only' (White + Grey?) 2) To the swimming pool pump that sends pool
water through the Heat exchanger (Note 1) 3) to the boiler, or Orange
wire of existing mid position valve to demand heat from the boiler
(and circulating pump). (Note 2)

Note 1 - This is only 100 watts so not to much for the existing 3 amp
fuse, but is outside so I need to make sure it has an RCD in the path.
Note 2 - I had a concern about 'feeding back' the live from this new
circuit into the existing 3 position valve via the orange wire, but
this already happens via the Cylinder stat, so I believe it wont be a
problem?

All comments welcome

Thanks
Kevin

In an earlier contribution to this discussion,
wrote:

Hi

Well the subject says most of it really I currently have a 2 zone
(CH & HW) Y Plan system and am looking for electrical circuit layouts
to extend this into a 3 zone system (CH, HW & Heat Exchanger for
swimming pool).

I am looking to keep the existing mid position valve, and add another
mid position valve in the 'feed' to the existing mid position valve.
Now I know that makes my electrics more complicated, as I can't go to
a relatively simple 'S Plan Plus' system, but it make my plumbing a
lot easier.

Whilst I would like to go to a 'fully functioning' system with all 3
zones and combinations of those zones available, a simpler circuit
that simply turned on swimming pool pump, boiler and mid position
valve to 'Heat Exchanger only), at the expense of ignoring any demand
from the CH or HW systems would be fine.

I have spent some time searching this group and google, finding the
odd comment about 'it gets complicated', but never finding answers.
With the number of people installing swimming pools, and the number of
Y plan systems out there - many people must have done this before?

Thanks in advance
Kevin

Why is it so difficult to use three 2-port valves, and do it properly rather
than cobbling up something with two 3-port valves?

The problem with 3-port valves is that the electrics for position control is
all mixed up with the switching for boiler and pump control, whereas with
2-port valves the two functions are completely isolated from each other.
Whilst a 3-port valve works ok (most of the time) in the specific
application for which it was designed, things get very complicated if you
stray outside of that application.
--
Cheers,
Roger
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