Hi,

My immediate problem is no DHW.

I have searched this group and I think I have the following CH/HW
setup

1.“Conventional” gas boiler i.e. Feeds a (poorly) lagged copper
cylinder via an indirect coil from the boiler
2.Supplementary electric immersion heater in HW cylinder
3.Two 2-port ACL Lifestyle valves controlled by the Honeywell
controller
4.Various water tanks in the loft

Now, various pipes connected to the HW cylinder are scalding hot
but the HW delivered at the taps is tepid.

I am thinking the 2-port valve on the HW side has failed. I haven't
yet traced the various water pipes and I need to study more about how
such a system is connected and should operate (and fail) but I need
help on the following.

I am guessing I can determine if the problem is a failed motor /
valve by “forcing” the valve open while the HW setting on the
controller is on. Now, the problem is, I can't find any online
information about the ACL Lifestyle valve. Does anyone know these
devices? There is a little black “switch” on top of each valve – I
would have thought this was a manual override to open or close the
valve but the bit of plastic just “waggles about” when I fiddle with
it – certainly there is no feeling that a switch is being operated
that might cause a motor to open or close a valve.

If I can force the valve open and satisfy myself the motor is the
problem does anyone know of a supplier for the “actuator” part of the
valve? I can't find online a reference and I guess it is an obsolete
device.

If I can't override the motor, can I detach it from the valve and
use a screwdriver to force the valve open?

If by trying to override the valve I determine the HW problem
(probably) isn't due to the valve, what else might be worth looking
at?

Naive question. Are the 2-port valves on the boiler / supply side
of the circuit or the “demand” side of the circuit? I am thinking they
should be on the demand side to enable either circuit to be switched
independently – giving independent HW and CH. I can understand the
operation of a 2-port valve on the sealed loop that goes around the
radiators but I can't understand how such a valve would work on the HW
side. Surely the DHW just comes off the top of the HW cylinder – and
the water removed is replaced by cold water supplied from the tank in
the loft. So what flow is the second 2-port valve controlling?