Gas BBQ Washer

[CJLees01]

Recent hot weather meant I dusted off my old gas BBQ and fired it up. After a few minutes I found flames come out behind one of the control knobs... Disconnected the gas and took it apart.

Gas bottle feeds a horizontal pipe which runs behind the knobs. The knobs then open a valve to allow the gas to flow out to the burners running front-to-back (right angles to the horizontal pipe).

Problem appears to be a perished washer between the control valve and the horizontal pipe, so a little gas was escaping and ignited. Replacing the washer should fix the leak.

Problem is that it's a weird washer that I'm not used to, so I don't even know where to look for a new one (or what it's called). It's sandwiched between a pipe and the control value that rus at right angles.

Anybody know what it's called please or when I can buy a new one?

 

[CJLees01]

Here's a photo of the washer in place. It creates a seal between the control valve and the black (horizontal) pipe.

 

[lostinthelight]

If it feels very soft it my be a special gas silicone sealant, if not maybe a fibre washer but best not to mess with gas.
https://www.ebay.co.uk/i/261825645533?chn=ps&dispItem=1&adgroupid=39910041817&rlsatarget=pla-300869767895&abcId=1088896&adtype=pla&merchantid=101770876&poi=&googleloc=1006790&device=t&campaignid=805055692&crdt=0&ul_ref=http%3A%2F%2Frover.ebay.com%2Frover%2F1%2F710-134428-41853-0%2F2%3Fmpre%3Dhttps%253A%252F%252Fwww.ebay.co.uk%252Fi%252F261825645533%253Fchn%253Dps%2526dispItem%253D1%26itemid%3D261825645533%26targetid%3D300869767895%26device%3Dt%26adtype%3Dpla%26googleloc%3D1006790%26poi%3D%26campaignid%3D805055692%26adgroupid%3D39910041817%26rlsatarget%3Dpla-300869767895%26abcId%3D1088896%26merchantid%3D101770876%26gclid%3DCKfEuofO2dQCFUO-7QodLs0M0A%26srcrot%3D710-134428-41853-0%26rvr_id%3D1241712261639

 

[Burnerman]

Sure looks like silicone to me!
John

 

[CJLees01]

Thanks guys.

Yes, definally rubber/silicone. It's not flat though, but moulded to the shape (although I guess that may just be through compression)?

Is it possible to replace these?

 

[Burnerman]

The theory with silicone is that it moulds itself to the shape required on assembly - but it sure sounds iffy when dealing with gas
Can you show us the other connection?
John

 

[CJLees01]

Thanks John - I didn't realise that.

Which other connection are you referring to? In the photo I attached, I've got the brass control valve (and you can just see one of the "good" washers in place), and it is assembled next to the hole in the black pipe, which carries the gas from the bottle. There are some brass clamps too (not shown), which fit over the top of the black pipe and screw into the control valve to keep everything in place.

 

[Burnerman]

I think I've got it......the valve clamps onto the pipe, courtesy of the black rubber washer - which itself is sealed by silicone. Is that it?
John

 

[CJLees01]

Here are a couple of photos to explain.

The rubber washer sits around a nozzle in the brass control value. You then align the value to a hole in the black pipe and use the clamps to hold it in place. The idea appears to be that by clamping them together like this you can create a tight enough seal to prevent leaks. Does that make sense?

 

[Burnerman]

Yes, that's much clearer now, thanks!
If you were to fill the hollow where the clamps go with silicone and tighten things up, it should be just as it was before....which isn't really very good, gas wise!
John

 

[CJLees01]

Thanks very much John -I'll give it a go!

 

[lostinthelight]

Thanks very much John -I'll give it a go!

I this is a bottle gas BBQ then for piece of mind I would do some research into what silicone your going to use as Lpg is vastly different to natural gas in how it reacts with things, gas fitters need different certification to deal with the stuff.
litl

 

[Burnerman]

I just can't see that any silicone type of sealant would be deemed as being suitable for gap filling with any gas appliance......it just doesn't make sense safety wise.
I'm wondering now if the red part is actually a fibre washer, which had been coated with a sealant - sort of a belt and braces approach? The first of those two extra pics seems to show some sort of packing between the valve and the supply pipe.
For sure, there are many pipe sealants for LPG - Loctite 577 being one, Heldtite another - this BBQ must rely on something else?
John

Edit - a question for CJL......the red washer on your 3rd pic - does it have any substance to it - or is it just like a rubber band?
J.

 

[lostinthelight]

May find some info here: http://www.rubberwashers.co.uk/Silicone_Rubber_Washers
litl

 

[CJLees01]

I just can't see that any silicone type of sealant would be deemed as being suitable for gap filling with any gas appliance......it just doesn't make sense safety wise.
I'm wondering now if the red part is actually a fibre washer, which had been coated with a sealant - sort of a belt and braces approach? The first of those two extra pics seems to show some sort of packing between the valve and the supply pipe.
For sure, there are many pipe sealants for LPG - Loctite 577 being one, Heldtite another - this BBQ must rely on something else?
John

Edit - a question for CJL......the red washer on your 3rd pic - does it have any substance to it - or is it just like a rubber band?
J.

The red washer / packing is definitely made of a rubbery material and not fibre. It is far more substantial than a rubber band at about 3mm thick. It looks and feels just like the sort of hard washer you may find in a tap, but looks as if it was deliberately contoured to fill the gap between the control valve and the black pipe which carries the gas from the bottle.

The comments about whether washers like this should be used at all on gas BBQs make me a little concerned, but also confused -- why would these washers be there if they weren't suitable? I should clarify that the assembly we are talking about here is almost directly behind the knob, at least 10cm away from the flames, and separated by another piece of metal. So under normal operation, they should never really come anywhere close to heat. That said, my original problem is that a gap in one of these washers caused a gas leak which then ignited (and partially melted the washer)... so it is not impossible.

[Thanks for everyone's comments on this thread by the way -- I really appreciate the help!]