On 19/03/2019 15:33, Max Demian wrote:
On 19/03/2019 10:35, John Rumm wrote:
On 18/03/2019 23:35, Steve Walker wrote:
On 18/03/2019 19:11, ARW wrote:
On 18/03/2019 08:26, Brian Reay wrote:

Personally, I'd not feel comfortable without having an immersion
heater as a back up. While we've not had many issues with our
heating, not having hot water for showers etc is a big issue.

That's everyone with a combi boiler up **** creek then.

Apart from the ones with electric showers:-)

The very reason I have resisted changing to a combi-boiler.

I have noticed that it seems the option of having a combi *and* a hot
water tank is one that never seems to occur to many people, yet there
are good arguments for it. The tank can be heated from the CH side of
the boiler in the normal way - so you get all the tank advantages. The
boilers DHW side however can then be used to provide mains pressure
showers, and potable hot water to the kitchen etc.

That's basically a 'system' boiler. Which can deliver DHW at mains
pressure from the tank if desired.

A system boiler and combi are indeed similar - in that the system boiler
is typically based on the same platform, and just lacks a diversion
valve and plate heat exchanger.

The main difference in overall system however is that to get mains
pressure showers etc from the system boiler requires an unvented
cylinder or heat bank, which is a fairly substantial additional expense.

Replacing a heating only boiler with a combi and keeping an existing hot
water cylinder can be somewhat more cost effective, and still give some
of the same benefits at the expense of a bit of extra piping.



--
Cheers,

John.

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