weather compensator or not?

[robsant]

I have been advised to have a Vaillant Ecotec Plus 937. Should i make sure the Vaillant VRC 400 weather compensator is fitted at the same time?

The boiler will be in the center of the house, so not near an outside wall, so will that make it difficult to fit the outside sensor? i guess it could go to the roof where the flu will go but that is 4 meters away vertically.

Finally please can someone explain exactly what the weather compensator does.

Thanks,

Rob

[WDIK]

a compensator looks at the room temp, the outside temp and the set temp.
it the then calculates usually by learning from the Q factor of your home just what temperature to have the flow at using a multi variable algorithm based on learned data, as to how long it takes your home to achieve the set point.
in doing this it will instruct your burner to modulate till the desired flow setpoint is achieved.
in buildings with a very high Q often the outside sensor has little value.
optimisation is achieved by switching off in advance on a precalculated drop of say 1/2 degree in the last hr, and switching on to achieve a set temp at the set time according to inside and outside temp.
gives greater climatic control of both comfort and efficiency.

[howy1]

Hello , i had a weather compensator installed with my boiler and i am not convinced it was a good route to go , the other day it was 11 degrees outside and my rads were red hot , also i expected better gas bills but they have not materialised . You dont feel like you have any control of the system as an end user either , so tred carefully .

[WDIK]

howy1 wrote:

Hello , i had a weather compensator installed with my boiler and i am not convinced it was a good route to go , the other day it was 11 degrees outside and my rads were red hot , also i expected better gas bills but they have not materialised . You dont feel like you have any control of the system as an end user either , so tred carefully .

usually that because its been set up incorrectly

they do work they are my bread and butter

[simond]

Weather Comp varies the flow temp of the radiator water based upon the outside temperature.

The ratio between the two is set by a multiplier, based upon the insulation value of the property.

There is also an algorithm as the response is not linear, but we don't need to understand this. Some WC allow you to change the curve of the response.

If your property is uniformly insulated (either well or badly) WC can save energy by running the boiler in condensing mode for longer periods.

The Vaillant VRC430 is the new WC controller, the old VRC400 is a pain to use. The distance of the sensor is not too much of an issue as long as the cable is sized to prevent a significant volt drop.

The respondent saying his WC is no good will have the wrong response curve set in the memory, or a house with widely varying insulation values across different rooms.

[tonybhoy]

WDIK wrote:

howy1 wrote: Hello , i had a weather compensator installed with my boiler and i am not convinced it was a good route to go , the other day it was 11 degrees outside and my rads were red hot , also i expected better gas bills but they have not materialised . You dont feel like you have any control of the system as an end user either , so tred carefully . usually that because its been set up incorrectly they do work they are my bread and butter

Been trying to push them on Valliants but people don't like the sound of them running the heating system.

Personally I would have one in a minute,anything that can save even more money on fuel bills is got to be worth considering.


However WB CDIs are not set up for them software wise according WB tech.Not that I have a WB CDI

[WDIK]

tonybhoy wrote:

WDIK wrote: howy1 wrote: Hello , i had a weather compensator installed with my boiler and i am not convinced it was a good route to go , the other day it was 11 degrees outside and my rads were red hot , also i expected better gas bills but they have not materialised . You dont feel like you have any control of the system as an end user either , so tred carefully . usually that because its been set up incorrectly they do work they are my bread and butter Been trying to push them on Valliants but people don't like the sound of them running the heating system. Personally I would have one in a minute,anything that can save even more money on fuel bills is got to be worth considering. However WB CDIs are not set up for them software wise according WB tech.Not that I have a WB CDI

personally i have a 2005 greenstar 30he wonder if you can tell me, i fitted the tr2 room sensor and remote, it has its own opt comp, does it allow an outside sensor? is it a 10k?

sorry the wife lost the manual

[howy1]

Simond , maybe you summed it up when saying there are wide variations in insulation , house`s especially older ones may not be condusive to WC .

[WDIK]

howy1 wrote:

Simond , maybe you summed it up when saying there are wide variations in insulation , house`s especially older ones may not be condusive to WC .

that the Q

[tonybhoy]

WDIK wrote:

tonybhoy wrote: WDIK wrote: howy1 wrote: Hello , i had a weather compensator installed with my boiler and i am not convinced it was a good route to go , the other day it was 11 degrees outside and my rads were red hot , also i expected better gas bills but they have not materialised . You dont feel like you have any control of the system as an end user either , so tred carefully . usually that because its been set up incorrectly they do work they are my bread and butter Been trying to push them on Valliants but people don't like the sound of them running the heating system. Personally I would have one in a minute,anything that can save even more money on fuel bills is got to be worth considering. However WB CDIs are not set up for them software wise according WB tech.Not that I have a WB CDI personally i have a 2005 greenstar 30he wonder if you can tell me, i fitted the tr2 room sensor and remote, it has its own opt comp, does it allow an outside sensor? is it a 10k? sorry the wife lost the manual

WB don't do WC according to their tech guys.

Apparently the PCBs on WB don't have software written that allows WC and according to WB there is no demand for it

Give them a phone and ask,

01905754624

[WDIK]

then i just have a compensator wb

[WDIK]

if you need or want an opt comp have a few coster units kicking around
955 611's

[doitall]

Servowarn (honeywell) have been making WC's for years, mine is 26 + and has saved thousands on the fuel bill

Highly recommend if your guy knows how to set them up.

[D_Hailsham]

WDIK wrote:

a compensator looks at the room temp, the outside temp and the set temp. it the then calculates usually by learning from the Q factor of your home just what temperature to have the flow at using a multi variable algorithm based on learned data, as to how long it takes your home to achieve the set point. in doing this it will instruct your burner to modulate till the desired flow setpoint is achieved. in buildings with a very high Q often the outside sensor has little value. optimisation is achieved by switching off in advance on a precalculated drop of say 1/2 degree in the last hr, and switching on to achieve a set temp at the set time according to inside and outside temp. gives greater climatic control of both comfort and efficiency.

Q Factor is a new term to me in relation to buildings. I know what is meant by the Q of a tuned circuit in Electronics; but can't see how this can be applied to a building.

Please enlighten me.

[Agile]

I have not heard that term used for buildings but is quite a good analogy to a tuned circuit.

It is in "simple terms" related to the thermal mass of the building, the radiator output power and the heat loss of the building.

Easier to "learn" than calculate!

Tony