Hi,

I saw some plastic pipes in the local diy store.

"John guest speed fit 15mm BPEX" I think it should be easier to use these for my up coming full central heating installation.

The website says they can be used for central heating have a working temp up to 93 degrees with a MAX temp of 114 degrees for a "short time" they didn't say how short. In case of boiler thermostat failure.

Some questions I have.

Would you use these for central heating?
access is no problem (I have no floor boards yet) so alternative is 15mm copper.

What is the normal working temp of water output from a combi boiler?

What effect would the anti corrosion additive have on the seals?

How are you expected to know if your thermostat cut off on the boiler has failed?

cheers
Wig

In article ,
wig writes:

Hi,

I saw some plastic pipes in the local diy store.

"John guest speed fit 15mm BPEX" I think it should be easier to use
these for my up coming full central heating installation.

The website says they can be used for central heating have a working
temp up to 93 degrees with a MAX temp of 114 degrees for a "short time"
they didn't say how short. In case of boiler thermostat failure.

Some questions I have.

Would you use these for central heating?
access is no problem (I have no floor boards yet) so alternative is
15mm copper.

Well, since you asked, I installed central heating about 3 years
ago and used copper with soldered joints as I know from past
experience it lasts (in this case, probably longer than I will).
Maybe plastic would too, but I don't have any past experience
to back that up, and saw no point taking the risk.

What is the normal working temp of water output from a combi boiler?

Central heating max is normally around 85C.

What effect would the anti corrosion additive have on the seals?

None.

How are you expected to know if your thermostat cut off on the boiler
has failed?

You hear girgling noises, followed by hissing noises,
followed by a loud bang. ;-)

More seriously, boilers tend to have overtemp cutouts,
and a sealed system will have a fallback of a pressure
relief valve.

--
Andrew Gabriel

wig wrote:


Hi,

I saw some plastic pipes in the local diy store.

"John guest speed fit 15mm BPEX" I think it should be easier to use
these for my up coming full central heating installation.

The website says they can be used for central heating have a working
temp up to 93 degrees with a MAX temp of 114 degrees for a "short time"
they didn't say how short. In case of boiler thermostat failure.

Some questions I have.

Would you use these for central heating?

yes, I've used speedfit (pex) and hep2o (pb) for ch systems and parts of
systems with no problems. The first metre of pipework from the boiler is
still supposed to be in copper on most boilers.

wig wrote:

I saw some plastic pipes in the local diy store.

"John guest speed fit 15mm BPEX" I think it should be easier to use
these for my up coming full central heating installation.

Could well be...

The website says they can be used for central heating have a working
temp up to 93 degrees with a MAX temp of 114 degrees for a "short time"
they didn't say how short. In case of boiler thermostat failure.

Some questions I have.

Would you use these for central heating?

I have done a short section of an extension to the CH in it when I
needed to play "dodge the joist" on my loft conversion.

What is the normal working temp of water output from a combi boiler?

85 for normal, less for a condensing one.

What effect would the anti corrosion additive have on the seals?

none in theory.

How are you expected to know if your thermostat cut off on the boiler
has failed?

I refer you to one of Andy's former posts:

http://www.diyfaq.org.uk/humour.html#uninstalling


--
Cheers,

John.

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"John Rumm" wrote in message
...
wig wrote:

I saw some plastic pipes in the local diy store.

"John guest speed fit 15mm BPEX" I think it should be easier to use
these for my up coming full central heating installation.

Could well be...

The website says they can be used for central heating have a working
temp up to 93 degrees with a MAX temp of 114 degrees for a "short time"
they didn't say how short. In case of boiler thermostat failure.

Some questions I have.

Would you use these for central heating?

I have done a short section of an extension to the CH in it when I
needed to play "dodge the joist" on my loft conversion.

What is the normal working temp of water output from a combi boiler?

85 for normal, less for a condensing one.

The working temp on a condensing boiler is what you want it to be, depending
on control system boiler. If you want 82C then there are condensing boilers
that will provide this continuously.




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Doctor Evil wrote:

The working temp on a condensing boiler is what you want it to be, depending
on control system boiler. If you want 82C then there are condensing boilers
that will provide this continuously.

I think the thrust of what I was saying is "less than the pipe is rated
at - irrespective of boiler type"

--
Cheers,

John.

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"John Rumm" wrote in message
...
Doctor Evil wrote:

The working temp on a condensing boiler is what you want it to be,
depending
on control system boiler. If you want 82C then there are condensing
boilers
that will provide this continuously.

I think the thrust of what I was saying is "less than the pipe is rated
at - irrespective of boiler type"

You were. Stop telling porkies. You are squirming like Dracula.

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Doctor Evil wrote:

You were. Stop telling porkies. You are squirming like Dracula.

What are you babbling about now?


--
Cheers,

John.

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I saw some plastic pipes in the local diy store.

"John guest speed fit 15mm BPEX" I think it should be easier to use
these for my up coming full central heating installation.

The website says they can be used for central heating have a working
temp up to 93 degrees with a MAX temp of 114 degrees for a "short time"
they didn't say how short. In case of boiler thermostat failure.

Some questions I have.

Would you use these for central heating?
access is no problem (I have no floor boards yet) so alternative is
15mm copper.

What is the normal working temp of water output from a combi boiler?

What effect would the anti corrosion additive have on the seals?

How are you expected to know if your thermostat cut off on the boiler
has failed?

My year 2000 build house has copper pipes from boiler in garage to airing
cupboard tank, copper to loft tanks, including expansion overflows but all
the pipes for hot water, for showers and from CH pump are all plastic Osma
Gold push fit. I queried why so much copper work during snagging and was
told its because if there is a boiler fault and it starts boiling the water
it can vent safely (???) etc without any pipes melting.....

There are also two thermostats externally on top of the boiler one attached
to pipe set at 90C and other set at 6C. I assume overtemp and frost stat.