checking safety devices on gas hob and oven

[Hobo128]

Just to change the subject because this thread is so fresh and im doing my acs too,
When purging existing pipework say after a service or something do you have to work out a purge volume to purge it or can you just purge 0.01 m3 of gas through. I understand that you have to work out purge volumes to check its within your limits.

 

[g60rge]

there will be thermo-couple, do not confuse it with ignitor.
You can light one of the burners and blow it. FSD should shut the gas within 60 sec max.
You can put your hand on the cooker and feel when FSD does work

ah i see the fsd in a hob is a thermoelectric valve

 

[g60rge]

hang on,

flame is lit on hob
i cut off the gas
after 60 secs it click shut
i turn gas back on and do a tightness test to check it has shut off and not passing gas to the burner - it passes
gas control is still on
how does it then go back to normal ie gas is allowed back in - is it when the control has returned to the off position?[/QUOTE]
no just press down on control knob and relight burner,doesnt matter what position , flame touches t/couple again and stays lit

just like on the fire place.

im so happy right now thanks every1

 

[dancinplumba]

just like on the fire place.

im so happy right now thanks every1

yes, well done just like a fire 🙂

 

[g60rge]

Just to change the subject because this thread is so fresh and im doing my acs too,
When purging existing pipework say after a service or something do you have to work out a purge volume to purge it or can you just purge 0.01 m3 of gas through. I understand that you have to work out purge volumes to check its within your limits.

if the gas pipe has been opened, i would do a purge calculation and follow the correct procedure to remove explosive mixtures!

 

[Syty]

it should click up to 60 sec. not after. Usually it does before

 

[Hobo128]

if the gas pipe has been opened, i would do a purge calculation and follow the correct procedure to remove explosive mixtures!

But what if you cant see the pipe work and you dont know how many fittings or how much 22mm pipe runs though the ceiling? Are you only doing purge volume caculations to check if you are allowed to purge it with out igniting. I am confused. Alot of the time you can see the pipework and you cant go ripping floor boards up.

 

[Syty]

Just to change the subject because this thread is so fresh and im doing my acs too,
When purging existing pipework say after a service or something do you have to work out a purge volume to purge it or can you just purge 0.01 m3 of gas through. I understand that you have to work out purge volumes to check its within your limits.

You have to purge installation if you had pipework open. If you did work on the boiler with isolation valve closed than no need to purge.

 

[Hobo128]

You have to purge installation if you had pipework open. If you did work on the boiler with isolation valve closed than no need to purge.

Yeah sorry mate i know this but what if for instance i have cut the pipe work and have to purge but cant see the pipe work to get the IV.

 

[Syty]

well if installation is up to 28mm it would be 0.01m3

 

[Hobo128]

So why do you need to work out a purge volume ?

 

[Hobo128]

well if installation is up to 28mm it would be 0.01m3

So why do you need to work out a purge volume ?
I mean cant you just purge 0.01m3 through everytime if the pipe work is not greater that 28mm. Dont forget im doing my acs soon and need explanation.

 

[GrahamM]

So why do you need to work out a purge volume ?
I mean cant you just purge 0.01m3 through everytime if the pipe work is not greater that 28mm. Dont forget im doing my acs soon and need explanation.

Correct. The standard purge volume for a G4/U6 meter with 28mm pipe is 0.01m³ as Syty states.
Only if bigger meter or greater than 28mm pipe does this change.

 

[kirkgas]

Just to change the subject because this thread is so fresh and im doing my acs too,
When purging existing pipework say after a service or something do you have to work out a purge volume to purge it or can you just purge 0.01 m3 of gas through. I understand that you have to work out purge volumes to check its within your limits.

check your notes and get your head round this you seem to be mixing a couple of things up
depending on meter and/or pipe size you only need to purge 0.01m3, if above 28mm or U16 meter there is a calculation to do, but a purge calculation isnt done to see if it is within limints of your work scope, the calculation is to work out how much gas to purge and whether you purge to air with no ignition or constant ignition
the calculation to decide whether you cvan work on it is IV (Installation Volume) and if over 0.035m3 isnt domestic

 

[kirkgas]

if the gas pipe has been opened, i would do a purge calculation and follow the correct procedure to remove explosive mixtures!

i wouldnt do a purge calculation until i had done a visual inspection to see what meter and pipes were fitted, as you dont need to calculate every install

 

[kirkgas]

But what if you cant see the pipe work and you dont know how many fittings or how much 22mm pipe runs though the ceiling? Are you only doing purge volume caculations to check if you are allowed to purge it with out igniting. I am confused. Alot of the time you can see the pipework and you cant go ripping floor boards up.

you never need to know how many fittings are on an install to work out purge volume, its down to meter and/or pipe size, if you cant see all the pipework you need to work on a best endeavour, say 28mm pipe disappears under the floor and 8m away 22mm pipe appears up as you dont know where it drops down simply take it as 28mm all the way, the reality is it wont make much difference, remember we are nearly talking about IV and PV in the same thread, max IV for domestic ticket is 0.035m3 (approx 90m x 22mm pipe with an E6 meter, so you will never go over in a domestic as you wont get any gas out of the pipe if the appliance is 90m away from the meter, if there is any 35mm pipe or a U16 meter you need to work out IV before you start, (o.035m3 max for domestic) if you can work on it you need to work out PV so you need PV of the meter and then calculate pipe lengths (again if you cant see all the pipe or where it reduces assume larger size) once you add up all the pipe volumes, add 10% for fittings (thats why you dont need to know how many there are) then multiply answer by 1.5 lastly add PV of meter, if under 0.02m3 purge to vented area, if over 0.02m3 you need to light it as soon as you start purging

 

[dancinplumba]

nice one kirkgas, lots of helpful information, and a lot of typing 🙂

 

[mutley racers]

So, on a U6 meter, you have to purge times the badge capacity which is 0.355 and this has to be burned. Do you just use a lighter at the hob? As you are not able to use electricity?

 

[mutley racers]

So when you guys say turn the gas off and wait for the click, do you mean just turn the gas off on the tap? Not like on the isolation valve like any other appliance? Am sure you wouldnt disconnect it from the bayonet fitting. Or would you?

 

[mutley racers]

ok, I have looked in my Viper and gas book and it says that for a U6 meter with 28mm pipe, you purge 0.01m3. And you do not need to light it. Which on the dial, is just between increment 3 and 4. But, if on my acs assessment, i lit the gas at the cooker, would it be allowed? As, it is recommended to in both my viper and Corgi to light. If so, what do i use to light it? A lighter or bit of paper?

Thanks for all the help guys