Another Gas Rate

[Floyd]

When training I was always shown to do the gas rate this way on a metric meter.

Note down the last three digits and time for 2 minutes.
Record the reading after the 2 minutes are up and minus the 1st from the second reading.

example: last 3 digits only: 1st reading 060, 2nd reading 158
158 - 060 = 98

Then 98 divide by 120 (seconds) = 0.82 x 38.6 = 31.7kw is this figure gross or net as I could never get a straight answer from the trainers.

Sorry I know you guys must have this question over again.
Does anyone do their calcs this way, as it seems the easiest way to me.

 

[aggis]

It be gross.

 

[GQuigley67]

delete this post

 

[GQuigley67]

even simpler way is when you get the difference times it by 321 to get your kw's gross

example

.158 - .060 = 0.098 x 321 = 31.4 Kw

although slightly different answers, it is still pretty much the same and within tolerance

 

[ratrace]

Divide by 1.1 to get the net.

 

[Floyd]

Its a Baxi instant 105e boiler manual states Heat input 34.3kw net. So gross is x 1.1 = 37.7kw.
31.7kw gross in my calc. Not within tolerance and obviously under gassed.
The burner Pressure is 13 and should be 13.4. if I tweak this up from 13 to 13.5 will this make a difference on the gas rate?

 

[Blackcatgas]

Yes it will affect the gas rate, a spanner rather than grips makes this easier to adjust, its in the instructions

 

[Billy Bob Bob]

Its a Baxi instant 105e boiler manual states Heat input 34.3kw net. So gross is x 1.1 = 37.7kw.
31.7kw gross in my calc. Not within tolerance and obviously under gassed.
The burner Pressure is 13 and should be 13.4. if I tweak this up from 13 to 13.5 will this make a difference on the gas rate?

take it up to 13 .4?,is the flow rate adequate in the first place, ?

 

[Floyd]

Working pressure is 20mbar and flow rate of water is more than adequate.
Any advise GM more than appreciated. Apologies for the lack of experience but a strive to learn more and more.

 

[Billy Bob Bob]

does it have the yellow or white gas valve solenoid?

 

[Billy Bob Bob]

[DLMURL="http://www.partsarena.com/baxi/"]PartsArena[/DLMURL]
mi,s how to adjust burner pressures

 

[capitanpugwash]

Its a Baxi instant 105e boiler manual states Heat input 34.3kw net. So gross is x 1.1 = 37.7kw.
31.7kw gross in my calc. Not within tolerance and obviously under gassed.
The burner Pressure is 13 and should be 13.4. if I tweak this up from 13 to 13.5 will this make a difference on the gas rate?

When you say not within tolerances, during my training I was told that it should be +5% to -10% but you would not find this written down.... Is it written anywhere? Thanks

 

[CMairiD]

Nearly the same was said in my course (all but the -10%). We were told this +/- 5% was an old BG rule of thumb and we'd never find it written down.

 

[SafeGasInstall]

gas rate I was told and use is

meter reading last 3 numbers let say 800 after 2 min 940

so 940-800=140 X 3O min =4.2m3/h x 10.72=45.24KWgross

45.24kw / 1.1=41.12 kw net

 

[leelister6]

Divide by 1.1 to get the net.

It's 1.11 to get net, used to be 1.1

 

[bobgarden]

Time over minutes then divide by 2 to find minutes then times by 60 to find m3 per hour.

 

[bobgarden]

Forgott to add buy one of these CORGIdirect Gas Rating Slide Rule Natural Gas - Domestic - GRB1 | Domestic Gas | Corgi Direct