On 18/03/2018 16:16, newshound wrote:
On 18/03/2018 13:51, John Rumm wrote:
On 17/03/2018 21:36, newshound wrote:
On 13/03/2018 10:04, John Rumm wrote:
On 13/03/2018 03:05, The Natural Philosopher wrote:
On 12/03/18 22:09, John Rumm wrote:
In comparison, I made the change and am very pleased with the
(massive) improvement in performance...

It really all depends on the circumstances...

The thought of going bacl to header tanks and low pressure hot water
just amuses me really.

If you already have a vented system that works well, a fast recovery
cylinder, and have pumps installed for showers, then there is not much
value to be had ripping and replacing it for the sake of it.

+1

When I went from a combi (I already had a separate vented immersion tank
running a shower) to a system boiler, I just put in an ordinary modern
cylinder with heating coil, not a special fast recovery one. Plus an ST
pump for DHW, and a double ST for the shower.

Much less complication

I would have thought if you need to replace a cylinder and install two
pumps, I am not sure that really qualifies under the "less complexity"
category!

No, I already had the shower pump plumbed in to the old cylinder. Even
so I'd have said there was more plumbing and electrics with a vented
system.

Electrics about the same[1], plumbing; Vented has a feed from a cold
cistern plus a vent (plus additional feeds to each shower ideally).
Unvented does not need those - just a feed from the mains, but it does
need a separate discharge pipe and then (short) connection to an
expansion vessel.

[1] Some have an additional over temp stat that you can put into service
as a backup backup system.

and no problem with recovery times.

If its a relatively recent one, then it will be fairly quick recovery
anyway. How the system is zoned will also have a big influence on
recovery times.


I will admit I gave the cylinder full priority when it needs heat (Is
that W rather than Y plan? ICBA to look it up.

Yup, W is like Y plan but with a diversion valve rather than a mid
position valve.


--
Cheers,

John.

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