"Edward W. Thompson" wrote in message
...
Have just found a drip from the bottom of my hot water cylinder so I
guess its time to replace it! I need some advice.

The cylinder is probably 15 years old and is lagged with expanded
polystyrene, I guess. It is an indirect cylinder with an immersion
heater. Looking at the catalogues it appears an identical cylinder is
available with the correct configuration of inlets and outlets. So
far straight forward to replace ;-).

With respect to replacement. There is a shut off cock for the cold
water in and a gate valve on the CH boiler hot inlet to the coil
(think it is the inlet). There is no isolation on the other side of
the coil (outlet).

My question is do I need to drain down the CH system to replace? What
crossed my mind is I could put a cork into the outlet from the CH
header tank in the loft that should stop drainage from the outlet side
of the coil when I disconnected, at least in theory. Any thoughts on
this?

With respect to the immersion heater. Do you think I will be able to
get it out of the old cylinder bearing in mind it has been there 15
years or so? I know I will need to buy/rent a spanner but are these
things in to stay once they are this old? Further, do you think it
sensible to replace the immersion heater anyway as I guess they don't
last forever?

All guidance will be much appreciated.

When replacing a cylinder go for a quick recovery m,model. Part L is 'not'
quick recovery. They go by names of Super Duty Ultra Cal and the likes.

Quick recovery takes all the boilers output heat up very fast and are
cheaper to run. You existing boiler may not take full advantage of the coil
as the coil may be capable of taking a boiler much larger, but when you
change the boiler, in time, it certainly will show even more dividends.