https://media.brizo.com/MandI/106401%20Rev%20D.pdf
Hi Steve L
Try this link, it should take you to technical pages that you require.
Hope this helps you.
Any vertical vent pipe (usually going to atmosphere) bent back on itself 180 degrees to prevent water
or foreign object ingress.
Open vent over F & E tank on heating and over CW storage tank off of cylinder.
Try grasping the connector on either side with your hands and try to turn it.
If you can get it moving then give it a few twists in both directions and finish off
with the bottom facing the top.
This has worked for me in the past.
The installation instructions for the 18sxi clearly state that the mains must be maintained
uninterrupted at all times.
From the installation manual:
"The mains electrical supply must be maintained at all times in
order to provide domestic hot water.
Do not interrupt the mains supply with a...
The braided fill pipe has been fitted the wrong way round.
Check first that the non return valve is working correctly by opening the isolating valve on
the loose end of the braided pipe.
Remove the filling hose from the top after the check valve and fit the isolating end to the nut (close the...
The arrow on the zone valve would be pointing to the cylinder if on the flow.
You say that the valve is on the return from the cylinder then the arrow should
be pointing away.
It would seem you have mounted the valve the wrong way round.
Certainly should get vessel size sorted as could be constantly be
discharging if under sized.
Many back boilers can be upgraded from open vent to sealed system,
and some can run sealed without modification.
You should consult the manufactures instructions or contact the manufactures direct...