Probably an easy question for you hardened DIY'ers but as an avid
bodger taking on a bodger job.....

I'm putting a new central heating system into a 3 bed detached house,
decided to go for a combi system becuase they look the easiest...

What's the better plan - Themostatic valves on each radiator or a room
temperature guage wired into the boiler? (or both???)

If I go RTV's I assume I need one radiator without?

Bonus question : Can I use the heated towel rail / raadiator as this
bypass so its always hot? How about the summer?

Last question - copper or plstic for the piping - or is it just
personal preference?

Thanks in advance - sorry if these are in an FAQ somewhere - if so can
someone post a link?

cheers,

Paul.

What's the better plan - Themostatic valves on each radiator or a room
temperature guage wired into the boiler? (or both???)

To comply with Approved Document Part L, you need a boiler interlock that
totally cuts boiler heating when the house is warm. The two main methods
(although any method you can think of would be fine) a

1. A room thermostat in a room without a TRV and TRVs in all other rooms.
2. TRVs on all radiators and a flow sensor to cut boiler power when all are
closed.

Method 1 can be divided into separate zones, each with their own timing and
temperature settings. In these cases, you need a room thermostat per zone.
You can even subzone to the room level, in which case, there will be no TRVs
at all, as all rooms will have a room thermostat and, hence, don't need
TRVs. Method 2 is rarely used.

As a rule, it is best to install programmable thermostats and leave the
boiler programmer (if present) on 24 hours. This is because a programmable
thermostat has certain features that are rarely implemented at the boiler.

a) Programming/manual override can be done in the comfort of your living
room, rather than a skanky unlit cupboard under the sink.

b) "Off" doesn't mean off. It means a separate night temperature, such as
10C, preventing condensation, damp and frost.

c) The thermostat can make predictions about how long it will take to warm
up and anticipate the temperature change by the appropriate amount.

Last question - copper or plstic for the piping - or is it just
personal preference?

Plastic where hidden. Chromed copper on display. If you do it right, you can
used 15mm chromed copper for the last 30cm between the radiator and under
the floorboards and plastic elsewhere.

Bonus question : Can I use the heated towel rail / raadiator as this
bypass so its always hot? How about the summer?

I would use an automatic bypass valve rather than a radiator. For the towel
rail on a combi boiler, I'd plumb it like a normal radiator with its own TRV
(or zone), but consider an additional electric element wired to a 1 hour
boost button for summer preheating of towels.

Christian.

On Wed, 14 Jul 2004 07:08:21 -0700, Paul wrote:

Probably an easy question for you hardened DIY'ers but as an avid
bodger taking on a bodger job.....

I'm putting a new central heating system into a 3 bed detached house,
decided to go for a combi system becuase they look the easiest...

What's the better plan - Themostatic valves on each radiator or a room
temperature guage wired into the boiler? (or both???)

If I go RTV's I assume I need one radiator without?

Bonus question : Can I use the heated towel rail / raadiator as this
bypass so its always hot? How about the summer?

Last question - copper or plstic for the piping - or is it just
personal preference?

Thanks in advance - sorry if these are in an FAQ somewhere - if so can
someone post a link?

cheers,

I would endorse most of what Christian McArdle has replied.

You don't say wether you are going for a combi boiler or stored HW.
If the former then likely the bypass is done internally in the boiler.
If the latter then I'd put the bathroom towel rail on as the bypass.
Theoretically you don't need a bypass if using Y plan (3 port valve)
controls (but I'd recommend S-plan + bathroom towel rail as bypass).

If using chromed copper, note that you will have to: Either use a
compression fitting onto the plastic and you MUST use the correct sleeve
supporting inserts on the plastic. Or you can abrade the chrome pipe to
copper and use a push fit connector.

If you have suspended floors to route the plastic pipe through, you will
need a right-angle drill or driver (not a £10 plastic gear box) to bore
the joists. But the jobs become a dream as you drag the plastic from A to
B as one run!

--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html

(Paul) wrote in message om...
Probably an easy question for you hardened DIY'ers but as an avid
bodger taking on a bodger job.....

I'm putting a new central heating system into a 3 bed detached house,
decided to go for a combi system becuase they look the easiest...

What's the better plan - Themostatic valves on each radiator or a room
temperature guage wired into the boiler? (or both???)

If I go RTV's I assume I need one radiator without?

Bonus question : Can I use the heated towel rail / raadiator as this
bypass so its always hot? How about the summer?

Last question - copper or plstic for the piping - or is it just
personal preference?

Thanks in advance - sorry if these are in an FAQ somewhere - if so can
someone post a link?

cheers,

Paul.

Arrrh fellow bodger, please to meet you. I'm about 1 yr ahead of you,
and had to answer some very similar questions.

Mine is a bog standard 3 bed semi also, wall mounted thermostat (Combi
is programmable on the front of it) in the hallway, all rads with TRVs
(looks good for the resale), ones in the hallway and kitchen open full
all the time. I placed a 15mm copper bypass at the end of the run
(furthest point from the combi) between flow in and out on the hallway
rad under the floorboards. Within the bypass I placed a stopvalve just
incase all flow went this way and I could close it a little (I never
used it, but I'm pleased it's there)

Bonus question : Can I use the heated towel rail / raadiator as this
bypass so its always hot? How about the summer?

Radiator as a bypass not a good idea, flow in is restricted in and out
of radiator, 6mm rings a bell (not too sure though) so you'd need two
rads open all the time to get to 12mm. You need a 15mm bypass so hence
build a bypass into it, be sure to place it at the end of the run
though.

Me I placed a wooden towel rail above a K2 (double radiator with fins
in between) rad in the bathroom, towels dry very quick.

- Heated towel rail on a combie ... dunno, sure it's possible though.

URL
http://www.plumbcenter.co.uk - Full product search - keywd radiator
Results : click on info (Technical jargon is explained)

HTHs - Oliver.
Pop me an email if you think I can help further.