New Boiler = Room Stat = Part 'P' & Part 'L' question (long)
 

"Christian McArdle" wrote in message
...

Nope. If the return cools the house has dropped in temp and/or the TVRs
have opened.

********.

Say the outside temperature is 30C. The rads require no heat, therefore
the
return temp drops below 71C. What prevents the boiler firing?

If that is a problem a simple outside stat set to 20-22C will prevent all
that.

There is nothing in your scheme that
prevents the boiler firing if the house
is hot. OK, there is something to stop
the boiler firing if the house is hot
AND the system is already running.
However, if the system has stopped

Stopped. If on the time clock then the burner is switch off too.

and cooled down, then it will restart,
cycling forever, despite there being no
call for heat at all.

New Boiler = Room Stat = Part 'P' & Part 'L' question (long)
 

If that is a problem a simple outside stat set to 20-22C will prevent all
that.

I'm not sure if that would be OK. I believe the call for heat is based on
the room temperature within the zone, not on outside temperature.

Stopped. If on the time clock then the burner is switch off too.

Indeed. But that is not an interlock based on the call for heat for the
individual heating zone.

Let's face it, a flow switch is a much more reliable and compliant
installation than a difficult to debug differential temperature based
system.

Christian.

New Boiler = Room Stat = Part 'P' & Part 'L' question (long)
 

.. wrote:

in relation to the Part P bit, would pulling a single, unbroken, cable /through/
a kitchen be classed as work /in/ the kitchen ?

Probably not (at least not for that reason), but it would depend on
where it was and how it was routed. Under a kitchen floor or in ceiling
space would usually be fine. Chased into a wall it might count since it
would need to follow the allowed cable zones - and this can and does
pose a potential risk if not done correctly - more so in a bathroom /
kitchen.


--
Cheers,

John.

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New Boiler = Room Stat = Part 'P' & Part 'L' question (long)
 

Doctor Drivel wrote:

If that is a problem a simple outside stat set to 20-22C will prevent
all that.

LOL...

this is classic Drivel - start with a dodgy bit of design. Kludge loads
of extra kit on to it each time people identify holes in the original
design. Keep going until you have a massivly complex arrangement that
still does not meet the actual requirements and costs way more (in both
time and money) to implement than doing it the right way in the first
place.

There is nothing in your scheme that
prevents the boiler firing if the house
is hot. OK, there is something to stop
the boiler firing if the house is hot
AND the system is already running.
However, if the system has stopped


Stopped. If on the time clock then the burner is switch off too.

That ain't the same as an interlock - it need to work when the time
switch says "run", but the actual house temperature is warm enough
without any further heating.


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

New Boiler = Room Stat = Part 'P' & Part 'L' question (long)
 

"John Rumm" aka pat-n-dave wrote in message
...
Doctor Drivel wrote:

If that is a problem a simple outside stat set to 20-22C will prevent all
that.

LOL...

pat-n-dave, do you think you are trend in your new Essex Chav clothes?

New Boiler = Room Stat = Part 'P' & Part 'L' question (long)
 

"Christian McArdle" wrote in message
...

If that is a problem a simple outside stat
set to 20-22C will prevent all that.

I'm not sure if that would be OK.
I believe the call for heat is based on
the room temperature within the zone,
not on outside temperature.

The idea is to stop the burner. An outside stat caters for high temp stops
during the day. Cool in the morning warm during the day, so burner (and
pump) off

Stopped. If on the time clock then the burner is switch off too.

Indeed. But that is not an interlock
based on the call for heat for the
individual heating zone.

Let's face it, a flow switch is a much
more reliable and compliant
installation than a difficult to debug
differential temperature based
system.

Firstly you need to install a mechanical valve (drain down etc). The flow
switch requires the pump to operate full time. If all TRVs are closed the
pump opens up the auto by-pass. and give boiler flow and mechanism to
detect if there is flow with the flow switch which is on the CH rad circuit
away from the by-pass loop. It will work. With a system boiler where the
boiler controls the pump you may need a timer to test the flow by operating
every 2 mins or so; if flow operate, if none stay off (more complexity).

A couple of stats can do the same thing and save money in operating costs
too. On a condensing boiler it can also feed the boiler with a low return
temp improving efficiency. It just means you have to design and balance the
system properly.

New Boiler = Room Stat = Part 'P' & Part 'L' question (long)
 

Hugo Nebula abuse@localhost wrote:
In relation to Part P; strictly speaking, any electrical work in the
kitchen is controlled. However, if your installer is CORGI registered, he
is exempt from giving notice provided the installation is, "as a necessary
adjunct to or arising out of other work being carried out by the
registered person".


Thanks muchly for that information that could well have saved me quite a bit
of cash.

Rob

New Boiler = Room Stat = Part 'P' & Part 'L' question (long)
 

A couple of stats can do the same thing and save money in operating costs
too.

It against building regulations, as it can still provide burner operation
when there is no call for heat. There is frequently no call for heat with an
outside air temperature of 20C. Clearly a proper interlock system will
provide better operating costs.

It would also be very temperemental. As the pump wears out, it might provide
a different speed/pressure, so the differential temperature will change. The
return temperature may respond oddly to changes in conditions. All in all
the system sounds completely impractical and over complicated.

Christian.





"Doctor Drivel" wrote in message
reenews.net...

"Christian McArdle" wrote in message
...

If that is a problem a simple outside stat
set to 20-22C will prevent all that.

I'm not sure if that would be OK.
I believe the call for heat is based on
the room temperature within the zone,
not on outside temperature.

The idea is to stop the burner. An outside stat caters for high temp stops
during the day. Cool in the morning warm during the day, so burner (and
pump) off

Stopped. If on the time clock then the burner is switch off too.

Indeed. But that is not an interlock
based on the call for heat for the
individual heating zone.

Let's face it, a flow switch is a much
more reliable and compliant
installation than a difficult to debug
differential temperature based
system.

Firstly you need to install a mechanical valve (drain down etc). The flow
switch requires the pump to operate full time. If all TRVs are closed the
pump opens up the auto by-pass. and give boiler flow and mechanism to
detect if there is flow with the flow switch which is on the CH rad
circuit
away from the by-pass loop. It will work. With a system boiler where the
boiler controls the pump you may need a timer to test the flow by
operating
every 2 mins or so; if flow operate, if none stay off (more complexity).

A couple of stats can do the same thing and save money in operating costs
too. On a condensing boiler it can also feed the boiler with a low return
temp improving efficiency. It just means you have to design and balance
the
system properly.

New Boiler = Room Stat = Part 'P' & Part 'L' question (long)
 

"Christian McArdle" wrote in message
...

A couple of stats can do the same
thing and save money in operating costs
too.

It against building regulations, as it can
still provide burner operation
when there is no call for heat.

You could say that about an integrated thermal store. No call for heat yet
the burner is running heating a cylinder. Lag the flow, return and the
by-pass pipes and you are in the same situation.

There is frequently no call for heat with an
outside air temperature of 20C.

So, the outside stat saves energy, and a lot too

Clearly a proper interlock system will
provide better operating costs.

This is one.

It would also be very temperemental.
As the pump wears out, it might provide
a different speed/pressure, so the
differential temperature will change.

It will not be temperamental at all.

The return temperature may respond oddly
to changes in conditions. All in all
the system sounds completely impractical
and over complicated.

Over complicated? Two stats and some lagging? Get real. What wastes energy
is the standard interlock of stat in the hall with no TRV on the rad. People
overset the hall wall stat so the rest of the house is warm, as the hall is
not representative of the whole house. The coldest and draftiest room in the
house then has too much heat pumped into it wasting energy.

I put a pipe stat on the return of a relatives system which doesn't have
TRVs and an old cast-iron boiler. It stopped a hell of a lot of cycling and
promoted efficiency as lower temps are generally more efficient. I set the
pipe stat on the boiler CH return to 58C so the boiler never condenses. The
garage wall behind was north so I fitted a stat in a box outside set to 21C.
They installed Double glazing and 1 foot of insulation in the loft so a flow
temp of 70C was fine. The fuel bills went down noticeably, all because of a
few stat. It now has a new condensing boiler.

New Boiler = Room Stat = Part 'P' & Part 'L' question (long)
 

Over complicated? Two stats and some lagging?

What is complicated is the control logic, as simply relying directly on the
return temperature will provide weird operation without some processing.

What wastes energy is the standard interlock of stat in the hall
with no TRV on the rad.

Yes. I hate the idea of having it in the hall. This is why my house
currently has 3 heating zones, with another 2 to come. The stats are in the
most frequently used (or only) rooms in the zone, so provide optimal comfort
in the right place.

Christian.

New Boiler = Room Stat = Part 'P' & Part 'L' question (long)
 

"Christian McArdle" wrote in message
...

Over complicated? Two stats and some lagging?

What is complicated is the control logic,
as simply relying directly on the
return temperature will provide weird
operation without some processing.

It will not. When it comes back hot the house is up to temp. Simple. You
balance the system to suit, which should be done anyway.

What wastes energy is the standard
interlock of stat in the hall
with no TRV on the rad.

Yes. I hate the idea of having it in the
hall. This is why my house
currently has 3 heating zones, with
another 2 to come. The stats are in the
most frequently used (or only) rooms
in the zone, so provide optimal comfort
in the right place.

New Boiler = Room Stat = Part 'P' & Part 'L' question (long)
 

The message ews.net
from "Doctor Drivel" contains these words:

What wastes energy
is the standard interlock of stat in the hall with no TRV on the rad.
People
overset the hall wall stat so the rest of the house is warm, as the hall is
not representative of the whole house. The coldest and draftiest room
in the
house then has too much heat pumped into it wasting energy.

That might be the case in your hovel Drivel but more adequately designed
houses would have a vestibule which would make the hall the least drafty
room in the house. Never the less as you might just recall I am a firm
advocate of putting the room thermostat in the living room if that room
does not have a supplementary heating source.

And no my hovel doesn't have a hall. It wasn't considered necessary in
peasants accommodation hundreds of years ago.

--
Roger Chapman

New Boiler = Room Stat = Part 'P' & Part 'L' question (long)
 

"Roger" wrote overt Rogerness in message
k...
The message ews.net
from "Doctor Drivel" contains these words:

What wastes energy
is the standard interlock of stat in the hall with no TRV on the rad.
People
overset the hall wall stat so the rest of the house is warm, as the hall
is
not representative of the whole house. The coldest and draftiest room
in the
house then has too much heat pumped into it wasting energy.

That might be the case in your hovel Drivel

** snip Rogerness **

His new Essex Chav clothes for Xmas are getting the best of him. I bet he
bought a white van to one of the boys too. Sad but true.