viessmann cant change gas correction factor

[monkeysballs]

hi, thought id have another go but i cant change the gas correction factor on the boiler in either the user setting or the installer menu's

it just stays at 1.0000 no matter what i type i mean its not an issue except i want to use the data for working some stuff out regarding degree days so id like to just have ch usage amounts without having a false reading from dhw production

anyone been able to fix it

 

[monkeysballs]

soo it seems i can only set between .7000 and 1.0000 yet my bill states a correction factor of 1.02264

 

[fixitflav]

soo it seems i can only set between .7000 and 1.0000 yet my bill states a correction factor of 1.02264

Don't know what you mean by correction factor, but 1.02264 is to convert the CV (MJ/m3) from 1 atm (or bar, can't remember which) and 0°C to typical pressure at the meter 20mb and room temperature. AFAIK all suppliers use the same factor.

 

[monkeysballs]

well in the manual for the boiler option 1098.4 gas volume correction factor

value is used on the gas suppliers bill used for gas consumption data

by default its set to 1.0000

the correction factor stated on my bil is 1.02264


id like to correct it so the consumption parts of the data the boiler collects are correct so i can accurately log gas usage for dhw and ch separately

But as they wont let me specify a value higher than 1.0000 then the figures will never be anywhere near accurate

 

[fixitflav]

i want to use the data for working some stuff out regarding degree days

Just for curiosity, what does this mean, what are degree days?

in the manual for the boiler option 1098.4 gas volume correction factor value is used on the gas suppliers bill used for gas consumption data

Can you give the full wording? Is the 1098.4 like a paragraph number, or is it used in a calculation, if so, what? As you've said, the correction factor stated on the bill is 1.02264

id like to correct it so the consumption parts of the data the boiler collects are correct so i can accurately log gas usage for dhw and ch separately

Sounds like your boiler measures and records gas flow, separately for CH and DHW. How does the total compare with the gas meter? Whatever the correction factor, the readings will give you a split between CH and DHW. You'll be billed on the meter readings (with 1.02264 factor) in any event.

 

[denso13]

id like to correct it so the consumption parts of the data the boiler collects are correct so i can accurately log gas usage for dhw and ch separately

1.0000 is the upper limit.

 

[fixitflav]

1.0000 is the upper limit.

View attachment 313270

But what is it correcting, to what? The gas supplier uses 1.02264

 

[denso13]

But what is it correcting, to what?

It's to match the correction factor on the gas bill.

 

[fixitflav]

It's to match the correction factor on the gas bill.

Do you mean the user notes the volume (total) recorded by the boiler, compares that with the gas meter figure, and adjusts the boiler correction factor till they're the same? Hoping it doesn't need to be > 1! The correction factor on the gas bill doesn't come into it, that's only used to calculate kWh from metered volume.

BTW what boiler is your insert from? I've looked at a few Viessmann manuals and can't find it.

 

[monkeysballs]

the boiler is vitodens 200w b2kf 30kw

so yeah in theory the boiler can apportion gas usage for DHW and CH separately so i can see how much the wife is using for her shower

regarding the degree days its a method for working out the performance of the heating in relation to the outside temp so you say last jan i used 800kWh but the jan before i used 1000kWh then yay the changes i made created a saving but what you forget was it was actually on average 3c warmer this jan than last

so using degree days it allows you to take the weather into consideration and actually see if you are now better off

the issue i have is currently my usage contains my DHW too so that skews the results as obviously DHW used gas isnt relevant

so if i can get and accurate reading from the boiler then great if not i will just try and work out an average DHW usage amount and apply that remembering to take out holiday etc

 

[monkeysballs]

i have no idea why they have an upper limit of 1.0000 though seems silly as the standard is 1.02264 when i manually use the correct factor it works out ish

my other issue its resolution is too small what it measure in m3 as currently my DHW usage was 3.03kWh on monday and 1.6kWh yesterday

 

[denso13]

Do you mean the user notes the volume (total) recorded by the boiler, compares that with the gas meter figure, and adjusts the boiler correction factor till they're the same?

It should be entered into the settings in the boiler and it does it's thing automatically.

BTW what boiler is your insert from? I've looked at a few Viessmann manuals and can't find it.

https://viessmanndirect.co.uk/files//b5c2530c-fe66-4c50-aba0-abc600f6c605/5593201VSA00001_1%20Download%20-%20Installation%20and%20service%20instructions.PDF

 

[fixitflav]

the boiler is vitodens 200w b2kf 30kw

so yeah in theory the boiler can apportion gas usage for DHW and CH separately so i can see how much the wife is using for her shower

regarding the degree days its a method for working out the performance of the heating in relation to the outside temp so you say last jan i used 800kWh but the jan before i used 1000kWh then yay the changes i made created a saving but what you forget was it was actually on average 3c warmer this jan than last

so using degree days it allows you to take the weather into consideration and actually see if you are now better off

the issue i have is currently my usage contains my DHW too so that skews the results as obviously DHW used gas isnt relevant

so if i can get and accurate reading from the boiler then great if not i will just try and work out an average DHW usage amount and apply that remembering to take out holiday etc

OK thanks, see what you mean

 

[fixitflav]

It should be entered into the settings in the boiler and it does it's thing automatically.

https://viessmanndirect.co.uk/files//b5c2530c-fe66-4c50-aba0-abc600f6c605/5593201VSA00001_1%20Download%20-%20Installation%20and%20service%20instructions.PDF

Thanks for that. I can't imagine Viessmann aren't aware of the 1.02264 factor, all I can think of is maybe in Germany they use the reciprocal of our factor, so might be worth trying 0.97786 and see if that gives agreement.

Presumably there's a way of interrogating the boiler for gas volume used, but I can't see it from a quick scan of the manual.

Also notice in 1098.5 "Calorific value" it's in kWh/m3 vs MJ/m3 (not that it's a big job to convert).

 

[monkeysballs]

will try 0.97786 and see what happens viessmanns email was useless

"This would need to be done by a Gas Safe engineer as you would need to do a Co2 analysis after this process."

then
"We have spoken to Tech and they advised that the parameters you have are factory set."

yeah no **** thats why i want to change them