"Aidan" wrote in message
oups.com...

Chris McBrien wrote:
I my bathroom and shower are
right next to and above the IMMERSION cylinder so that's where the main
hot
water usage is. The kitchen sink is at the other end of the house and
tends
to use the hot/warm water from the FIRE cylinder as it is closer.

If this is so, it suggests that you have the two cylinders connected in
parrallel. If so, when you turn on a hot tap, you will get some water
from both cylinders simultaneously. If one is hot and the other cold,
this will be a problem.

That is why it is a silly idea