My proposed central heating system comprises a boiler, four pumps, two
zone valves, three mixing valves and two controllers.

What's the best way to provide mains power to this lot? I was planning
to install a single "heating system" radial circuit using 4mm=B2 twin
and earth. This circuit would start at the consumer unit and snake its
way through the house from component to component before being
terminated at the boiler. Each component would have its own local fused
connection unit to isolate it electrically.

Does that solution seem OK? Any tips?

What's the best way to provide mains power to this lot? I
was planning to install a single "heating system" radial
circuit using 4mm² twin and earth.

Way too big. Use 1mm or 1.5mm. Much easier to work with and will actually
fit in the terminals! You can also use multiway flex after the FCU.

This circuit would start at the consumer unit and snake its
way through the house from component to component before being
terminated at the boiler.

Modern boilers usually have an internal isolator, which they like to cut off
the rest of the system. Generally, the main supply should direct go to the
boiler supply terminals and all other components (pumps, controllers etc)
should come off the switched output from the boiler. Don't confuse this
switched output with the "pump" output. Your boiler may not have one.

Each component would have its own local fused
connection unit to isolate it electrically.

Don't use an FCU for each component. You should have the entire system off a
single 3A FCU (or MCB) which comes before the boiler. Individual components
may be switched using standard (usually 20A, but smaller is fine) DP
switches, rather than FCUs.

Christian.

In article . com,
Pandora wrote:
My proposed central heating system comprises a boiler, four pumps, two
zone valves, three mixing valves and two controllers.

What's the best way to provide mains power to this lot? I was planning
to install a single "heating system" radial circuit using 4mm² twin
and earth. This circuit would start at the consumer unit and snake its
way through the house from component to component before being
terminated at the boiler. Each component would have its own local fused
connection unit to isolate it electrically.

Does that solution seem OK? Any tips?

I'd say you need to do a bit of learning about current consumption and
cable sizes. All the components you've mentioned take a tiny amount of
current and could *probably* be fed with the smallest TW&E - ie 1mm.

Which doesn't bode well for the design of a one off heating system.

--
*A woman drove me to drink and I didn't have the decency to thank her

Dave Plowman London SW
To e-mail, change noise into sound.

Christian McArdle wrote:

Modern boilers usually have an internal isolator, which they like to
cut off
the rest of the system. Generally, the main supply should direct go
to the
boiler supply terminals and all other components (pumps, controllers
etc)
should come off the switched output from the boiler.

My boiler has got this internal isolator. What is the point of it? If
you power down the boiler when you service it, you power down all the
controllers as well. Isn't there a chance they will lose their
parameter settings?

In article .com,
"Pandora" writes:
My boiler has got this internal isolator. What is the point of it? If
you power down the boiler when you service it, you power down all the
controllers as well. Isn't there a chance they will lose their
parameter settings?

Normally any electronic controls have something like 24h battery
backup, unless the rechargable battery has died (which happens).

--
Andrew Gabriel

My boiler has got this internal isolator. What is the point of it? If
you power down the boiler when you service it, you power down all the
controllers as well. Isn't there a chance they will lose their
parameter settings?

It's so that when you turn off the isolator, there are no voltages present
on the control wiring. Without it, the call for heat input could be live.

Christian.

"Andrew Gabriel" wrote in message
.. .
In article .com,
"Pandora" writes:
My boiler has got this internal isolator. What is the point of it? If

SNIP

OT but I emailed you 30 days ago Andrew. Today the message came back as
undeliverable?
Is there a problem with your mail collection?

John

In article ,
"John" writes:

"Andrew Gabriel" wrote in message
.. .
In article .com,
"Pandora" writes:
My boiler has got this internal isolator. What is the point of it? If

OT but I emailed you 30 days ago Andrew. Today the message came back as
undeliverable?
Is there a problem with your mail collection?

Sorry John. I stopped downloading that mailbox about 5 years
ago when it reached 1000 junk mails a day and perhaps only
a couple of genuine mails a month. If I've despamtrapped your
email address correctly, I've mailed you a usable email address.

--
Andrew Gabriel