Hi all
Planning to install a large wet underfloor heating system in my house 140m2

I want the system to be hardwired, ie no fancy control boxes, fancy electronics, etc
(this way I can always fault find + Im tight)

I would like to include a crude 'weather compensator ' to control the water tempurature.see
http://www.jbc-controls.co.uk/jbctrssn1.htm
http://www.savastat.co.uk/lcWeather.html

eg Outside tempurature 5oC - water temp 40oC
Outside tempurature 0oC - water temp 45oC
Outside tempurature -5oC - water temp 50oC

I can currently only think of one way of doing this.
1) Install 3 mixing valves 3 motorised valves and 3 outside thermostats
The valves could be cascaded and depending on the outside tempurature i could select a heat setting. - Downside its crude and would be expensive.

Any better ideas.

regards

Cameron

On 16 Sep, 10:59, Cameron wrote:

Any better ideas.

Yes. Electronic controller. One 3-port control valve, infinitely
variable flow temperature.

Weather compensations controls the heating flow temperature according
to the outside air temperature. One of the pit-falls for the unwary is
that simple weather compensation, whilst an advantage when the heating
& building is up to temperature, can't respond to the indoor
temperatures. On start-up the building is cold, but the heating is
still run at a reduced temperature because the heating doesn't
recognize this.

"Onetap" wrote in message
ups.com...
On 16 Sep, 10:59, Cameron wrote:

Any better ideas.

Yes. Electronic controller. One 3-port control valve, infinitely
variable flow temperature.

Weather compensations controls the heating flow temperature according
to the outside air temperature. One of the pit-falls for the unwary is
that simple weather compensation, whilst an advantage when the heating
& building is up to temperature, can't respond to the indoor
temperatures. On start-up the building is cold, but the heating is
still run at a reduced temperature because the heating doesn't
recognize this.

Most have room temperature influence.

"Cameron" wrote in message
...

Hi all
Planning to install a large wet underfloor heating system in my house
140m2

I want the system to be hardwired, ie no fancy control boxes, fancy
electronics, etc
(this way I can always fault find + Im tight)

I would like to include a crude 'weather compensator ' to control the
water tempurature.see
http://www.jbc-controls.co.uk/jbctrssn1.htm
http://www.savastat.co.uk/lcWeather.html

eg Outside tempurature 5oC - water temp 40oC
Outside tempurature 0oC - water temp 45oC
Outside tempurature -5oC - water temp 50oC

I can currently only think of one way of doing this.
1) Install 3 mixing valves 3 motorised valves and 3 outside
thermostats
The valves could be cascaded and depending on the outside tempurature i
could select a heat setting. - Downside its crude and would be
expensive.

Any better ideas.

regards

Cameron

Why 3 of everything? 3 zones?

Have one flow pipe from the boiler or thermal store. Have the compensator
control this to give the right temp. Off the flow have a manifold., From
this to the UFH zones. On the return the same, a manifold and the returns
from the UFH zones

Each zone may have solenoid valves to switch off or on to local room temp,
floor temp or whatever. The pump should be smart pump like a Wilo Smart or
Grundfos Alpha, so when the zones are off the pump stops (well slows up).
If the boiler requires flow then a by-pass valve needs to be fitted and no
smart pump. Have pipe stat on the flow set to 60C so that over hot water is
not sent into the zones.

On 16 Sep, 22:14, "Doctor Drivel" wrote:
"Onetap" wrote in message

ups.com...

On 16 Sep, 10:59, Cameron wrote:

Any better ideas.


Most have room temperature influence.

Yes, Drivel, some do. But what the OP wrote was this;

I can currently only think of one way of doing this.
1) Install 3 mixing valves 3 motorised valves and 3 outside
thermostats

Which clearly would have no inside sensor.
Got it?
Fool.

"Cameron" wrote in message
...

Hi all
Planning to install a large wet underfloor heating system in my house
140m2

I want the system to be hardwired, ie no fancy control boxes, fancy
electronics, etc
(this way I can always fault find + Im tight)

I would like to include a crude 'weather compensator ' to control the
water tempurature.see
http://www.jbc-controls.co.uk/jbctrssn1.htm
http://www.savastat.co.uk/lcWeather.html

Do you mean weather compensator or a "load compensator" like the Savastat?
Danfoss Randall do a weather compensator for £160. I saw a few for sale on
Ebay for £40 - now sold.

"Cameron" wrote in message
...
eg Outside tempurature 5oC - water temp 40oC
Outside tempurature 0oC - water temp 45oC
Outside tempurature -5oC - water temp 50oC

Crudest and cheapest is three outside stats and three pipe stats on the
flow. Cascade three outside stats.

Outside temperature less than - 5C:
ouside stat No 1 swiches in pipe stat set to 50C.
Pipe stat switches boiler
Temp rises above -5C
outside stat No. 1 breaks on temp rise,
switches over line to outside stat No. 2 set to 0C,
pipes stat set to 50C de-energised.
Outside stat No 2 energises pipe stat set to 45C
Pipe stat switches boiler
Temp rises above -0C
outside stat No. 2 breaks on temp rise,
switches over line to outside stat No. 3 set to 5C,
pipes stat set to 45C de-energised.
Outside stat No 2 energises pipe stat set to 40C

Have a high limit stat to cut out the boiler if it gets above flow temp of
55C to 60C.

Temp ranges:
below -5C 50C flow
between -5C and 0C 45C flow
between 0C and 5C 40C flow

Cameron wrote:
Hi all
Planning to install a large wet underfloor heating system in my house
140m2


This is good.

I want the system to be hardwired, ie no fancy control boxes, fancy
electronics, etc
(this way I can always fault find + Im tight)


This is not good.

I would like to include a crude 'weather compensator ' to control the
water tempurature.see
http://www.jbc-controls.co.uk/jbctrssn1.htm
http://www.savastat.co.uk/lcWeather.html

eg Outside tempurature 5oC - water temp 40oC
Outside tempurature 0oC - water temp 45oC
Outside tempurature -5oC - water temp 50oC

I can currently only think of one way of doing this.
1) Install 3 mixing valves 3 motorised valves and 3 outside
thermostats
The valves could be cascaded and depending on the outside tempurature i
could select a heat setting. - Downside its crude and would be
expensive.

Any better ideas.


Most of the electronics is simple. I have not head of electrically
adjusted temp regulators.

I just run mine flat out, and use a thermostat to cut the thing off when
the rooms are warm enough. A slightly smarter thermostat would be better
as I get about 1 degree overshoot.

The wiring is quite large, but simple. In essence apart from a relay to
wire or the boiler so that turning the boiler on for e.g. hot water
doesn.t fire the auxiliary UFH circulation pump, it is essentially no
worse than a normal CGH circuit with a couole of stat controlled TRV's
on sub zones.

I don't see why you would want to modulate UFH water temp.




regards

Cameron

"The Natural Philosopher" wrote in message
...
Cameron wrote:
Hi all
Planning to install a large wet underfloor heating system in my house
140m2


This is good.

I want the system to be hardwired, ie no fancy control boxes, fancy
electronics, etc
(this way I can always fault find + Im tight)


This is not good.

I would like to include a crude 'weather compensator ' to control the
water tempurature.see http://www.jbc-controls.co.uk/jbctrssn1.htm
http://www.savastat.co.uk/lcWeather.html

eg Outside tempurature 5oC - water temp 40oC
Outside tempurature 0oC - water temp 45oC
Outside tempurature -5oC - water temp 50oC

I can currently only think of one way of doing this. 1) Install 3 mixing
valves 3 motorised valves and 3 outside
thermostats
The valves could be cascaded and depending on the outside tempurature i
could select a heat setting. - Downside its crude and would be
expensive.

Any better ideas.

Most of the electronics is simple. I have not head of electrically
adjusted temp regulators.

See my other post on how to so it. Better buying cheap waeether compensator
as th cost may be about the same.

I just run mine flat out, and use a thermostat to cut the thing off when
the rooms are warm enough.


You run plastic UFH pipes at 80C? My God!!!

I don't see why you would want to modulate UFH water temp.

You don't know much about these things do you?