Hi,

We are greatly extending our house and with it fitting a new heating/
hot water system. In summary it will consist of the following..
- 2 system boilers
- Megaflow tank
- One room (zone) with water UFH
- 3 zones (1 per floor) for the heating
- 1 "zone" to cover the towel rails in the bathrooms so that they can
be warm in summer with the heating off
- secondary loop for the hot water to reduce draw down time of the hot
water in the other side of the house
- all rads with TRVs

The question is how on earth do I control all this???

Having looked her and search the web a lot, I have seen the following
"possible" solutions and was wondering if anyone here has a fairly
cost effective solution?

Option 1 - programmable room stats
The thought here was to have a programmable room stat per zone
(assuming the UFH is an additional zone) located in the hallway/
landing of each floor and in the room with UFH. Centrally control the
hot water and towel rails on a timer.

Seemed a good solution until my wife thought about the scenario where
we come in during a time when the heating is off and want to turn it
on again. We would have to go to each room stat and turn it on....

Option 2 - use some X10 controllers
I have not had any experience with these but in theory I guess you
could control them via a timer and also in the scenario of coming in
when everything is off, switch them on with a central controller(s)
from anywhere in the house. Has anyone used these? Is this a good
idea?

Option 3 - a comercial controller.
I saw that Honeywell seem to do a fancy controller which optimises the
bolier firing and timing based on your temperature requirements and
the outside temperature. I couldn't get a great deal of information
(nor find anyone who sold it!!) but believe it is called an AQ2000.
This would resolve the issue of managing the 2 boilers and the central
control when you get into the house but then provides the flip side of
how do you switch the heating on when you are upstairs?

In summary, despite a great deal of searching, I haven't been able to
come up with anything that is flexible and resolves the problems
above. Wouldn't it be great if you could call it to turn the heating
on on your way home (like you can with alarms to switch them off)??

All ideas and thoughts appreciated. Also, any issues with the current
design?

thanks in advance

Lee.

On 20 Jan, 13:05, wrote:
David Hansen wrote:
On Tue, 20 Jan 2009 03:29:32 -0800 (PST) someone who may be
wrote this:-

- 3 zones (1 per floor) for the heating

North/south zones are generally better, unless whole floors will be
unoccupied. With north/south zones weather compensation is easier as
is coping with solar gain.

Option 1 - programmable room stats [snip]

Seemed a good solution until my wife thought about the scenario where
we come in during a time when the heating is off and want to turn it
on again. *We would have to go to each room stat and turn it on....

Master time clock. Programmable thermostats have occupancy
programmed into them. Master time clock will enable or disable
output from every thermostat. Going out, turn off heating at master
time clock. Coming in, turn it on at master time clock, only those
rooms where the thermostat is programmed for occupancy at the time
will warm up.

Even better is to separate the concepts of timer zones and temp zones,
andhave one temperature zone per room. Its cheap to do with bimetal
stats. Your timers each control several rooms, but local to each room,
each room has its own stat. This means you can switch off or turn down
the heat in any one room at will. You then have a master switch to
turn the whole system down to frost protect, and use that when you go
away. Note on frost protect setting the system relies on a single
central stat, the individual room stats are effectively not operating
in this mode since they will all always call for heat, but the system
will be controlled then by the frost stat..

NT- Hide quoted text -

- Show quoted text -

individual room stats sounds like an idea. Do you have a link to a
bimetal stat as I haven't heard of these before. How would I get each
floor to come on at different times?

wrote in message
...
Hi,

We are greatly extending our house and with it fitting a new heating/
hot water system. In summary it will consist of the following..
- 2 system boilers
- Megaflow tank
- One room (zone) with water UFH
- 3 zones (1 per floor) for the heating
- 1 "zone" to cover the towel rails in the bathrooms so that they can
be warm in summer with the heating off
- secondary loop for the hot water to reduce draw down time of the hot
water in the other side of the house
- all rads with TRVs

The question is how on earth do I control all this???

Firstly a simple system change. Get rid of the Megalow and fit a heat
bank/thermal store. This does the DHW at mains pressure.
All the zone can be taken off the store of water directly or a small header
for the 3 rads zones and bathroom rail zone.
Each zone has a pump and check valve in front. Simple and the same price as
zone valves and less problematical.
The rad and rail zones can have Smart pumps on each, which means TRVs all
around and no silly by-pass valves or wall thermostats.
The UFH can be taken directly off the thermal store cylidner lower down
where temperaures are lower. Use a single speed pump and blending valve.
The boilers? Take each one to the store cylidner with its own flow and
return. No header. No need to sequence the boilers. Have two cylinder
stats for anti-boiler cycling purposes - the boiler comes in the reheat the
whole cylidner ASAP in one long efficvient burn.

That is the mechanical side sorted.

Control:
Timer for DHW, which calls in the boilers. In summer one can be manually
switched out. Each boiler requires its own isolating switch.

Cheap single stage Timer for each zone. It switches on a relay.
The relay switches the Pump for the zone and the boilers. Relays are approx
£5 from Maplin and put in a nice large plastic box.
Have a wall stat for the UFH between the timer and the pump.

The timers can all be in one position in the house.

Each function (zone, boioer DHW) work totally independently. In winter have
the DHW come well before the CH, so that the CH rads get hot immediately by
dumping the hot water directly into heating loops from the cylidner store.

For an explanation:
http://www.heatweb.com

These will make the thermal store/heat bank for you. Specify the number of
tappings, etc. Stainless steel.
http://www.advanceappliances.co.uk/g...e_systems.html

Get back if you wnat to know more.

On Tue, 20 Jan 2009 05:04:00 -0800 (PST) someone who may be
wrote this:-

Seemed a good solution until my wife thought about the scenario where
we come in during a time when the heating is off and want to turn it
on again. *We would have to go to each room stat and turn it on....

Master time clock. Programmable thermostats have occupancy
programmed into them. Master time clock will enable or disable
output from every thermostat. Going out, turn off heating at master
time clock. Coming in, turn it on at master time clock, only those
rooms where the thermostat is programmed for occupancy at the time
will warm up.

As you say, the master clock is great for switching everything off or
reducing everything (e.g. only have heating on for 1 hour a day when
on holiday or something) but unfortunately, doesn't solve the "I now
need the heating on" issue.

Depends on the settings, but seems to fit the "we come in during a
time when the heating is off and want to turn it on again" condition
which was specified.

In an individual room which one is using at an "unusual" time, just
adjust the temperature on the thermostat temporarily. When finished
set it back or leave it until the next time period, when it should
go back to timed operation.


--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54

individual room stats sounds like an idea. Do you have a link to a
bimetal stat as I haven't heard of these before. How would I get each
floor to come on at different times?

Cheap thermostats are bimetal, as are almost all old stats. The idea
is to keep the inital costs down and thus improve payback. Bimetals
work more or less as well as electronic, and are far more reliable.
http://www.screwfix.com/prods/84704/...oom-Thermostat


You could implement your originally suggested zoning, so each floor is
on its own time control, the only difference is you have one
thermostat per room instead of one stat per floor zone. This means the
room stats must control the rads in that room via a valve of some
type. Electricaly controlled TRV heads are available for under £30,
such as the Danfoss RA 2912.

There are choices as to how you control boiler firing, depending on
the details of the setup.

Maybe it would be better to talk of floor sized 'zones' and room sized
'subzones' to reduce confusion.


NT

PS this gives more info on the Danfoss products
http://randall.danfoss.com/PCMPDF/410.pdf

wrote:

The question is how on earth do I control all this???

Having looked her and search the web a lot, I have seen the following
"possible" solutions and was wondering if anyone here has a fairly
cost effective solution?

Option 1 - programmable room stats
The thought here was to have a programmable room stat per zone
(assuming the UFH is an additional zone) located in the hallway/
landing of each floor and in the room with UFH. Centrally control the
hot water and towel rails on a timer.

Seemed a good solution until my wife thought about the scenario where
we come in during a time when the heating is off and want to turn it
on again. We would have to go to each room stat and turn it on....


(Ignoring the boiler sequencing for a mo, and just looking at the room
and water temperature control)

If you went with this as a baseline, but added a separate programmer in
an accessible location that fed all the prog stats then you should be
able to achieve what you want. Program all the stats to achieve the
required temperatures that you need. Set them such that you maintain a
reasonable minimum fallback temperature when you think the zones will be
unoccupied and/or overnight. Set your timed programmer so as to achieve
the minimum level of running that you require when out or on holiday etc
using its "once" or "twice" setting. For normal operation switch it to
"always on" and let the prog stats do their stuff.

When you come in, you flick the programmer back to always on. The prog
stats will then set about heating any zone that is currently below its
target temperature for that time period.

Option 2 - use some X10 controllers
I have not had any experience with these but in theory I guess you
could control them via a timer and also in the scenario of coming in
when everything is off, switch them on with a central controller(s)
from anywhere in the house. Has anyone used these? Is this a good
idea?

Depends on how clever you want it to be - and how much effort you want
to put into getting it all working. Do a google on this group for some
of the information posted on this in the past.

All ideas and thoughts appreciated. Also, any issues with the current
design?

Have a look at this thread on sorting out the demands to the boilers:

http://groups.google.com/group/uk.d-...b1d3d6da1cca93


--
Cheers,

John.

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

John,

Thanks very much for your reply..... Sounds like a plan but I am a
little confused about the following

When you come in, you flick the programmer back to always on. The prog
stats will then set about heating any zone that is currently below its
target temperature for that time period.

In normal operation, wouldn't the programmer be set to "always on"
anyway as we are relying on the programmable stats to decide when
heating should be on by zone? If it wasn't for some reason, switching
it to "always on" wouldn't override the times set on the stats would
it. i.e. if the stat says turn off/ go to minimum temp at 10:00 and at
11:00 I switch the central programmer to "always on", the stat will
override it?

thanks

Lee.

writes:

You could implement your originally suggested zoning, so each floor is
on its own time control, the only difference is you have one
thermostat per room instead of one stat per floor zone. This means the
room stats must control the rads in that room via a valve of some
type. Electricaly controlled TRV heads are available for under £30,
such as the Danfoss RA 2912.

That's not electrically controlled; it's a remote bulb
connected by a capillary. I've not seen a Danfoss
thermoelectric head for anywhere near that cheap. The link
Richard Skeen posted in the "Timer TRVs" thread for
Heatmiser in-line wax valves was the cheapest I've seen, but
I don't know what TRVs the heads would fit, and I don't know
how easy it is to get the heads separately.

--
Jón Fairbairn
http://www.chaos.org.uk/~jf/Stuff-I-dont-want.html (updated 2008-04-26)

wrote:
John,

Thanks very much for your reply..... Sounds like a plan but I am a
little confused about the following

When you come in, you flick the programmer back to always on. The prog
stats will then set about heating any zone that is currently below its
target temperature for that time period.

In normal operation, wouldn't the programmer be set to "always on"
anyway as we are relying on the programmable stats to decide when
heating should be on by zone? If it wasn't for some reason, switching

Yes,

it to "always on" wouldn't override the times set on the stats would
it. i.e. if the stat says turn off/ go to minimum temp at 10:00 and at
11:00 I switch the central programmer to "always on", the stat will
override it?

This is true.

I was assuming you would set the stats such that they keep the house at
the temperature you require when you require it. However the addition of
the programmer would would allow you to reduce the heating for times
when you are not following your normal pattern of occupation - i.e.
everyone out for the day, or on holls etc. You would then have the timer
set to run the heating just enough to keep it ticking over. To be fair a
frost prevention stat would probably do this just as well.

If you particularly wanted to be able to force the heating on at a time
when the programmable stats are already satisfied, there is nothing
stopping you adding an override switch or programmer. A simple one that
has a "boost" facility would allow you to push one button and have the
heating run for an hour regardless of the stats being satisfied. However
I am not quite sure why you would want to do that unless you plan to
program the stats to a very low temperature for the bulk of the day when
you expect to be out, and need to account for unexpected periods of
occupation.

--
Cheers,

John.

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

If you particularly wanted to be able to force the heating on at a time
when the programmable stats are already satisfied, there is nothing
stopping you adding an override switch or programmer. A simple one that
has a "boost" facility would allow you to push one button and have the
heating run for an hour regardless of the stats being satisfied. However
I am not quite sure why you would want to do that unless you plan to
program the stats to a very low temperature for the bulk of the day when
you expect to be out, and need to account for unexpected periods of
occupation.

--

Hi John,

This is exactly what we wanted . However, I guess the programmable
room stats would turn a motorised valve on as well as firing the
boiler. In the case of hitting the boost button, the boiler may start
but the valves not open. Not sure if this is the way it works though?

thanks

Lee.

wrote:
If you particularly wanted to be able to force the heating on at a time
when the programmable stats are already satisfied, there is nothing
stopping you adding an override switch or programmer. A simple one that
has a "boost" facility would allow you to push one button and have the
heating run for an hour regardless of the stats being satisfied. However
I am not quite sure why you would want to do that unless you plan to
program the stats to a very low temperature for the bulk of the day when
you expect to be out, and need to account for unexpected periods of
occupation.

--

Hi John,

This is exactly what we wanted . However, I guess the programmable
room stats would turn a motorised valve on as well as firing the
boiler. In the case of hitting the boost button, the boiler may start
but the valves not open. Not sure if this is the way it works though?


With a many zones system, you wire all the contact for the motorized
valves in parallel and take the resultant two wires back to theboiler.
One goes to 'CH live'(may be timeswitched) and the other fires up the
pump/boiler.

That allows the stats that drive the valve motors to be on a different
live..useful as you may want to link into the local ring main for that.


thanks

Lee.

wrote:
If you particularly wanted to be able to force the heating on at a time
when the programmable stats are already satisfied, there is nothing
stopping you adding an override switch or programmer. A simple one that
has a "boost" facility would allow you to push one button and have the
heating run for an hour regardless of the stats being satisfied. However
I am not quite sure why you would want to do that unless you plan to
program the stats to a very low temperature for the bulk of the day when
you expect to be out, and need to account for unexpected periods of
occupation.

--


This is exactly what we wanted . However, I guess the programmable
room stats would turn a motorised valve on as well as firing the
boiler. In the case of hitting the boost button, the boiler may start
but the valves not open. Not sure if this is the way it works though?

You would connect your override button(s)/programmer across the contacts
of the room stat(s). That way it will fire the system/zone in exactly
the same way as the stat.

--
Cheers,

John.

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

On Thu, 22 Jan 2009 12:21:41 +0000, The Natural Philosopher wrote:

That allows the stats that drive the valve motors to be on a different
live..useful as you may want to link into the local ring main for that.

Ooo, no, please. The entire heating system should really be fed via a
single DP isolator switch. You don't want bits here and there live when
other bits or not. Apart from the safety aspect when working on the system
it's quite likely to confuse people if it acts strangely if a ring main
trips.

As this system is likely to "evolve" I'd run all the contacts of any
device back to a central wiring cabinet and do the appropiate cross
connections there. I've done that here and it makes changing things very
simple, like adding pump over run or possibly replacing the relays with a
PLC.

--
Cheers
Dave.

In article ,
writes:


If you particularly wanted to be able to force the heating on at a time
when the programmable stats are already satisfied, there is nothing
stopping you adding an override switch or programmer. A simple one that
has a "boost" facility would allow you to push one button and have the
heating run for an hour regardless of the stats being satisfied. However
I am not quite sure why you would want to do that unless you plan to
program the stats to a very low temperature for the bulk of the day when
you expect to be out, and need to account for unexpected periods of
occupation.

Hi John,

This is exactly what we wanted . However, I guess the programmable
room stats would turn a motorised valve on as well as firing the
boiler. In the case of hitting the boost button, the boiler may start
but the valves not open. Not sure if this is the way it works though?

thanks

Note that boilers aren't very good at driving tiny zones of a
radiator or two. A modern condensing boiler just won't be able
to modulate down to low enough power to drive so few radiators
without ending up cycling off and on, and that could well
counteract any gains you might expect by micro-zoning (and the
hysteresis before switching back on can mean your one radiator
has to cool quite a bit whilst you are still demanding heat).
You really need a more intelligent system that would look for,
say, the 3 zones which most need heating, to ensure there's
some minimum load and that you drive the zones into synchronising
their heating demands to some degree. One way around this is to
use a heat store, but then you're increasing the complexity,
cost, and maintenance, and it's unlikely you'll make any saving
that comes close to compensating for this.

Another trick I've done is that when all demand for heat ceases
and you tell the boiler to switch off, I switch the flow through
a zone which hasn't been operating, so that I cool the boiler
by dumping the heat into a cooler heating zone (where it stays
inside the house), rather than having the boiler blow it out of
the flue together with cooling the circulating water in the pipes.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]