gas rating cooker

[diablo13]

Hi guys, i am fairly new to the gas side of things and have a question ;i need to gas rate a cooker for commissioning and have done quite a few hobs but this is an oven/grill/4 ring appliance that gives one gas rate on the badge, do i rate each section seperately (ie grill on its own) on full aiming for the same rating on each section or all on at once or another combination.I should probably know but dont remember it coming up at college.Cheers

 

[kirkgas]

technically you should gas rate each thing on its own if you have the heat input of each from the MI's, (the reason behind it is one bit could be over gassed and one bit under cancelling each prob out by giving the correct answer, haha the troops who do real work will tear me apart for this one)
however the reaality is not enough people do gas rates ayway, so if you do the whole lot at the one time and get the right answer you are doing more than most, if you dont get the right total you will need to do them individually to suss out whats wrong, but again in the real world i would hope you would pick up the fault from the visual, like any other appliance it needs to be rated on max so turn up full and open the oven door to keep it lit

 

[mountainman]

Why would you go into so much detail?

 

[diablo13]

Because we were told in college if an appliance is over-gassed it can produce dangerous levels of CO

 

[kirkgas]

Why would you go into so much detail?

he said he was commissioning, so he MUST gas rate, what do you do when you fit a cooker?

 

[mountainman]

A cooker gas rate is not adjustable so as long as the inlet pressure is correct then the gas rate must be correct unless it has incorrect injectors fitted.
If that was the case then the flame size/picture would make further investigation obvious.

 

[gasmarc]

fair point , some people gas rate some dont some people just jot down whats on the data plate

 

[GrahamM]

I usually just fire the burners on and add the individual ratings up from MI's. Cooker/oven as long as all looks good job done.

I have came across the odd appliance that has no specific rate in MI's for oven/grill anyway.

 

[gasmarc]

I did a job before where a second hand cooker was being installed , I had to find a load of leaks in this big victorian house which took me 2 or 3 days , I eventually connected the cooker only for flames to come roaring out of it , The customer was screaming at this stage as her ex had given her this cooker in the first place

 

[dancinplumba]

A cooker gas rate is not adjustable so as long as the inlet pressure is correct then the gas rate must be correct unless it has incorrect injectors fitted.
If that was the case then the flame size/picture would make further investigation obvious.

how do you check inlet pressure ? has cooker got test point ?

 

[mutley racers]

some cookers have the test point on the rig to burners and taps. My boss sometimes just usually put the manometer over the injector with 3 rings on

 

[mutley racers]

so when gas rating a cooke ron full, do you open the cooker door and turn on full, the grill on full and 3 hobs on all at the same time?

 

[mountainman]

so when gas rating a cooke ron full, do you open the cooker door and turn on full, the grill on full and 3 hobs on all at the same time?

Theoretically yes, but it would be very unlikely that all of a cookers burners would be firing at full rate for any appreciable period, if ever.
The word applicable in the world of sparks is 'Diversity'

 

[johnnyplumb]

how do you check inlet pressure ? has cooker got test point ?

here's a tip for checking inlet / working pressure at cookers or hobs, keep hold of an injector from an old cooker that you have taken out, round off the hex and solder it into the brass sleeve from an old universal thermocouple. when you are checking working pressures, replace one off the injectors with this diy device. most plumbers just hold their manometer hose on the jet but this device can save gas leaking from the hose, especially when you have the other 3 burners lit at the same time.

 

[kirkgas]

so when gas rating a cooke ron full, do you open the cooker door and turn on full, the grill on full and 3 hobs on all at the same time?

surely when gas rating you do as above but with the 4 hobs on so that you are gas rating on max?

 

[mountainman]

Previous post was describing a method if determining working pressure, nothing to do with gas rate.

 

[mutley racers]

ok, sorry, i was getting confused with inlet working pressure with boiler and cooker. That is 3 rings

 

[AWheating]

you will def need mi if you have combined grill and oven for the seperate ratings.

 

[mickie]

holding the hose on an injector, i stopped doing this when my hand almost set a light..

i look at flame picture on the hot plates and always analyze ovens.. few ovens ive checked have looked ok, but the co has been over 500ppm

cookers are the biggest killers, so i'd rather just analyze as much as i can rather than gas rate it..

 

[ambrosia]

holding the hose on an injector, i stopped doing this when my hand almost set a light

or electrocute yourself with those ignition and gas knobs that are combined