i am not saying by any means that keeping all zones to a fully liveable temperature is best!! but it is best to keep the full thermal envelope of the building warm, I.E in the areas that you don't use that often (bear in mind you do lose heat in these areas unless you shut all doors and have them thermally insulated from normal living areas). personlly i have a 2 floor living space that i continue to warm 24/7 with my heating system adapted to suit the load off loss, (new build) and as regular standards would stipulate keeping my 2 zones warm 24/7 does save output against trying to rewarm and heat these ares just when i reuire them to be warm!!!!
Weather compensation & choice of pump
- Thread starter p7777m
- Start date
Sponsored Links
i always recommend keeping the thermal envelope of your building warm saves you energy rather than trying to heat the envelpe and the living space inbetween
A
ALEC1
I understood the OPs house to be 18kw heat load (hence the 418 boiler)...no real benefit in zoning, as the entire house is probably used throughout the day, except a couple of bedrooms. In reality it is probably 15kw once the radiators output has been taken into consideration, all speculation I know but probably correct
Of course energy consumption is related to usage...so a church hall used once a week should only be heated once a week, so on-off controls is best.
Houses by contrast are occupied for say 18 hours a day... maybe more like 24 hours a day, in such cases yes I do believe matching heat generated to heat lost with compensation controls is more efficient than turning things on and off, and that does mean heating being available to heat (at two different temperatures set back and normal)
There are many reasons for the savings offered by compensation controls... lower flow temperatures, less user interaction, necessary system designs, enhanced thermal inertia of the building all contribute to the savings made...at the end of the day thats what my clients confirm so I know they save money!
The vaillant and viessman weather compensation controllers both work with NO indoor sensing, and don't need it. It is not the same as those that just have an out door sensor and then need indoor sensing..thats why I make the distinction, have a look at viessmann's brochure on the subject
http://www.viessmann.co.uk/etc/medi...e.File.tmp/6pp Viessmann weather comp web.pdf
In both vaillant and viessmans case (200 series only) you should not use on-off controls, with all the others you can....but you are better off with a compensation controller! I think this is an important distinction, not least because of zoning when you need to give two lives to a boiler (which with vaillant can only be done using the vr 61/65 wiring centre
I thought the 400 series came out about 2 years ago....the heat exchanger being used previously on the ecomax....the 600 is about 6 years old...but I would expect more 600s out there...
Of course energy consumption is related to usage...so a church hall used once a week should only be heated once a week, so on-off controls is best.
Houses by contrast are occupied for say 18 hours a day... maybe more like 24 hours a day, in such cases yes I do believe matching heat generated to heat lost with compensation controls is more efficient than turning things on and off, and that does mean heating being available to heat (at two different temperatures set back and normal)
There are many reasons for the savings offered by compensation controls... lower flow temperatures, less user interaction, necessary system designs, enhanced thermal inertia of the building all contribute to the savings made...at the end of the day thats what my clients confirm so I know they save money!
The vaillant and viessman weather compensation controllers both work with NO indoor sensing, and don't need it. It is not the same as those that just have an out door sensor and then need indoor sensing..thats why I make the distinction, have a look at viessmann's brochure on the subject
http://www.viessmann.co.uk/etc/medi...e.File.tmp/6pp Viessmann weather comp web.pdf
In both vaillant and viessmans case (200 series only) you should not use on-off controls, with all the others you can....but you are better off with a compensation controller! I think this is an important distinction, not least because of zoning when you need to give two lives to a boiler (which with vaillant can only be done using the vr 61/65 wiring centre
I thought the 400 series came out about 2 years ago....the heat exchanger being used previously on the ecomax....the 600 is about 6 years old...but I would expect more 600s out there...
A
ALEC1
On another thread I found this:
Hello everyone I am a Viessmann 100 trained engineer . I was recommended to fit a 200 in my new house ( that is pretty different from the 100 ) by all Viessmann staff ie regional manager ...rep ... etc
it can be a bit tricky as the boiler is certainly the one with the highest specs on the market . I have an edwardian 4 bed with loft insulation and cavity walls ins... some new double glazing some fairly old doub glaz and bear floor boards at the mo.
I have set my high temp to 20 and have played with the heat curve for a month now ....
We have had a very unusual start of winter ( here in Eastbourne we got 13-14 degrees ) so my rads have not been coming very hot at all .... but the house has always maintained a nice temperature
I have had the heating timed ..all sorts of times on and off ....but it seems that the units burned are less if I have it on all day ...
With the temps outside quite high I have turned heat slope to 1.7 - 2.0 as I also have cast iron victorian radiators ... and the units of gas burned are a bit higher ( 5 a day ) . but I finally found that keeping the temperature to 20 when you want the heating on and the reduced temp 4 degrees less helps as the boiler come on on its own and tops up the rads and the pipework when its not timed....I only have Wc and this is how it works ... You can have a thermostat but it defeats the object as it will come on and off once the house has reached temp !
the Wc detects the temp outside and accordingly heats the house up ... there no sensor in the boiler for the temp inside the house .
the boiler knows that to achieve a set temp inside , the temp of the flow should always be lets say 30 degrees ( its just an example ! ) so everytime the boiler detects a loss of temp from pipework and rads it fires up to maintains it ! that s why the pump runs constantly .... so it spreads the heat until a little more is needed without the boiler having to stay on all the time or come on full blast to reheat the whole system up . Of course with WC the boiler will stay constantly in condensing mode so it will not fire up at full whack and thats where you make your savings on gas units .
When the temp outside does go under 10 degrees my rads have come on pretty hot ... and I m still using 4 units of gas a day that with my supplier is around 1 pound 50 ish a day that is nothing at all !!
Hope this helps
Read more: //www.diynot.com/forums/viewtopic.php?t=210138#ixzz1enKr5NsT
Hello everyone I am a Viessmann 100 trained engineer . I was recommended to fit a 200 in my new house ( that is pretty different from the 100 ) by all Viessmann staff ie regional manager ...rep ... etc
it can be a bit tricky as the boiler is certainly the one with the highest specs on the market . I have an edwardian 4 bed with loft insulation and cavity walls ins... some new double glazing some fairly old doub glaz and bear floor boards at the mo.
I have set my high temp to 20 and have played with the heat curve for a month now ....
We have had a very unusual start of winter ( here in Eastbourne we got 13-14 degrees ) so my rads have not been coming very hot at all .... but the house has always maintained a nice temperature
I have had the heating timed ..all sorts of times on and off ....but it seems that the units burned are less if I have it on all day ...
With the temps outside quite high I have turned heat slope to 1.7 - 2.0 as I also have cast iron victorian radiators ... and the units of gas burned are a bit higher ( 5 a day ) . but I finally found that keeping the temperature to 20 when you want the heating on and the reduced temp 4 degrees less helps as the boiler come on on its own and tops up the rads and the pipework when its not timed....I only have Wc and this is how it works ... You can have a thermostat but it defeats the object as it will come on and off once the house has reached temp !
the Wc detects the temp outside and accordingly heats the house up ... there no sensor in the boiler for the temp inside the house .
the boiler knows that to achieve a set temp inside , the temp of the flow should always be lets say 30 degrees ( its just an example ! ) so everytime the boiler detects a loss of temp from pipework and rads it fires up to maintains it ! that s why the pump runs constantly .... so it spreads the heat until a little more is needed without the boiler having to stay on all the time or come on full blast to reheat the whole system up . Of course with WC the boiler will stay constantly in condensing mode so it will not fire up at full whack and thats where you make your savings on gas units .
When the temp outside does go under 10 degrees my rads have come on pretty hot ... and I m still using 4 units of gas a day that with my supplier is around 1 pound 50 ish a day that is nothing at all !!
Hope this helps
Read more: //www.diynot.com/forums/viewtopic.php?t=210138#ixzz1enKr5NsT
Sponsored Links
I wouldn't get hung up on controlling the pump speed. The biggest influence on efficiency will be having a boiler that modulates down to a low enough level and a good control. I would get a System boiler and then your pump and bypass will all be integrated into one package. The least you will get then will probably be a two speed pump - low speed for CH and high speed for HW.
It depends on your layout of house, but is zoning really worth it or would TRVs work just as well? If you let the temperature of upstairs sink down too low then when you want to heat it up you will want to make two different demands on the boiler; a WC determined temp for downatairs and a higher temp for upstairs to ramp up the room temperature quickly. It all sounds too complicated. What about programmable TRVs to allow you to set an upstairs temperature profile?
you thought wrong
Use a fixed speed pump with WC. The WC controls are matching the water flow temperature to the heat losses.
In a fixed-temperature system the boiler runs at a fixed, high temperature and temperature control is by switching the pump and boiler on/off with the thermostat and throttling the flow with TRVs. It's fixed flow temperature, variable flow (rate and duration).
In a WC system, the temperature control is by modulating the flow temperature (assuming it has an indoor sensor). It''s fixed constant flow rate, variable flow temperature. Introducing another variable (pump speed) will start the controls hunting around and fighting one another. There is no point in having a variable speed pump, the TRVs should stay mostly open since they're fine trimming the room temperature only, the system resistance stays fairly constant and the flow rate should not vary.
A
ALEC1
burners do modulate without an indoor sensor...atags and brags .for examples start low and ramp up until the return begins to rise... so the demanded temp may be say 40c, but to achieve that it won't go to high fire.. if they can avoid it.
much the same with viesssmann and vaillant...
much the same with viesssmann and vaillant...
Yes, I know, I'm just comparing the two methods of controlling the room temperature. A simple WC system wouldn't have a room sensor and would modulate to maintain the flow temperature determined by the outside air temperature.
I don't think pure WC is a good idea on any house, but the best insulated. You can have 5 degc outside either with or without a strong wind. An average house is going to lose a lot more heat with a strong wind, but the outside sensor is still measuring 5degc in both cases. So you need an element of internal temperature measurement to modify the heating curve. You're still using WC, but with some feedback on the end result.
A
ALEC1
weather dependency with no indoor sensing works surprisingly well dumb rill...in fact it works phenomenally well...I have over 200 out there..everyone loves it!
note though its only possible on vaillant or viessmann vitodens 200s!
note though its only possible on vaillant or viessmann vitodens 200s!
So they're setup so that the heating curve supplies water at the temp required for the place of greatest demand and then TRVs do the rest. The TRV is the internal modifier.
I'm not knocking WC. I'm using on and Remeha boiler with an iSense control. This is another alternative to vaillant or viessmann. The iSense offers either straight WC or WC with room temperature correction (or just plain room temperature control).
A
ALEC1
no seemingly not.. but I am only talking about the vitotronic 200 and the vaillant 430 weather compensators (set with no internal sensing)...
In fact you can't add any internal sensing to the vitotronic..
I suspect that they calculate whole heat inputs into the building somehow..
I have seen an outdoor temperature of -2c and room temperature (measured with a thermometer of 20c) and a flow temp of 45c, with a heating curve of 1.7...and a target room temperature of 20c...
Night set back was quite high too.. about 16c..
This is not the same with other compensated systems, which de require trimming with TRVs, and other controls..
In fact you can't add any internal sensing to the vitotronic..
I suspect that they calculate whole heat inputs into the building somehow..
I have seen an outdoor temperature of -2c and room temperature (measured with a thermometer of 20c) and a flow temp of 45c, with a heating curve of 1.7...and a target room temperature of 20c...
Night set back was quite high too.. about 16c..
This is not the same with other compensated systems, which de require trimming with TRVs, and other controls..
A
ALEC1
I have the I sense too with out door sensor, but I gave up with that and just have indoor sensing...
DIYnot Local
Staff member
If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.
Select the supplier or trade you require, enter your location to begin your search.
Are you a trade or supplier? You can create your listing free at DIYnot Local
Sponsored Links
