"Set Square" wrote in message
...
In an earlier contribution to this discussion,
JB wrote:

"IMM" wrote in message
...

"Set Square" wrote in message
...
In an earlier contribution to this discussion,
JB wrote:

Are there any links to diagrams etc which would help me identify
the CH system I have installed in my late '70s house.
It's a pretty basic system with gas-fired boiler in the garage,
feeding an indirect cylinder in the airing cupboard above with a
circulating pump on the boiler return pipe next to the boiler.
There is no cylinder thermostat or room stat anywhere in the house.
The controller is a single channel electromechanical timer. There
is a manual valve to 'switch' between hot water and radiators.
I'm looking to replace the cylinder soon with a new one and
retrofit a modern electronic programmer with a cylinder stat and
room stat. The bit which confuses me is where do I put the 3-way
valve (or do I use a 2-way valve in place of the manual valve)?
Any help or links would be much appreciated.
Thanks,

JB

From what you say, your system is fully pumped but with the water
going either to the HW coil or to the radiators, but not both at
the same time. What does this manual valve look like - does it have
one input and two outputs - maybe arranged like a tee-piece? If so,
you could fairly easily convert your system into a Y-Plan by
replacing this valve with a 3-port mid-position valve.

Best no silly plan and use two plumps with check valves and a relay
in a box on the wall.

Best still fit a high flow combi as the boiler will be near the end
of its life. So much easier and effective in speed of installation,
ease and cost..and power showers for free.

I'll have to give this idea a closer look. Thanks very much for both
of your advice.
cheers,
JB

Whilst you could undoubtedly save a lot of fuel - and money - by
installing
a more modern boiler, you can also make a lot of improvements to your
current system, and benefit from some of the savings, for a fraction of
the
cost - without replacing the boiler at this stage. Installing zone valves
and thermostats so that the boiler and pump only run when needed will make
a
tremendous difference - especially if you also put TRVs on most of the
radiators.

If you are replacing the cylinder, buy one with fast recovery (big heat
exchanger inside) and well lagged with integral foam.

Be aware that - according to our friend IMM - combi boilers are the answer
to every maiden's prayer. In reality, they are not - and there is a lot to
be said for keeping a stored hot water facility.
--
I'll have to admit that is what I was originally going to do. Replace and
move the cylinder, fit TRVs throughout, and keep the old boiler until it
gives out. I've only just replaced the pump (not bad for 25yrs old) but the
boiler is in excellent condition according to the BG engineer who serviced
it a year or two ago.
Thanks again,
JB