Gas oven flames - the opposite problem!

[Sea Dog]

Having just read a post about a yellow oven flame and seen some clearly very knowledgeable answers, I was reminded of an issue I have with my Spinflo Caprice. The hob and grill burners burn fine, strong and steady with blue cones, but the oven flame has a tendency to rise above the jets, usually rising from the end opposite the ignitor and lifting like a wave before dropping back down. When initially lit, this can sometimes be to the point where it might loose the flame altogether and cut out. Too high a pressure would be my guess, though I can see no obvious adjustment and I'm sufficiently experienced a fiddler to know when not to!

 

Is my explanation clear enough for to someone to offer any diagnosis or advice? Thanks!

[Alf Roberts]

check the burner rack hasn't been dislodged. the symptom is too much air. on a modern oven I doubt it's adjustable but it might have an air screw.

[Sea Dog]

check the burner rack hasn't been dislodged. the symptom is too much air. on a modern oven I doubt it's adjustable but it might have an air screw.

 

Thanks Alf. I haven't checked anything yet other than to see if it was windy in there (there's plenty of vent but no real draft) so too much air sounds more like it.

[Alf Roberts]

on the old calor ovens ( for example) thr burner rack is just sitting on two lugs, not fixed down, so could get dislodged.

 

it's also possibly a partially blocked jet but if so the flame will also be smaller than normal.

Edited January 11, 2015 by Alf Roberts

[MoominPapa]

Had exactly the same problem with a Spinflo oven. Cured it with a new gas regulator. The old one had drifted ever so slightly high pressure. The hob and Morco had no problems, and weren't noticeably different after the replacement, but it fixed the oven problems completely. This design of oven seems to be very sensitive to even very small increases on gas pressure over the spec.

 

MP.

[Sea Dog]

Had exactly the same problem with a Spinflo oven. Cured it with a new gas regulator. The old one had drifted ever so slightly high pressure. The hob and Morco had no problems, and weren't noticeably different after the replacement, but it fixed the oven problems completely. This design of oven seems to be very sensitive to even very small increases on gas pressure over the spec.

 

MP.

 

Thanks MP - I'll try that after I've checked the burner is seated correctly since there's expense involved! Symptoms line up though, eh?

[MoominPapa]

Thanks MP - I'll try that after I've checked the burner is seated correctly since there's expense involved! Symptoms line up though, eh?

For sure, the symptoms you describe are identical to those I was seeing.

 

For the avoidance of doubt, the regulator I replaced was the main one in the gas locker. There's no regulator local to the oven, as far as I know.

 

MP.

Edited January 11, 2015 by MoominPapa

[MtB]

'Flame lift' as it's called can be notoriously difficult to diagnose. Especially when intermittent as the OP describes. I suggest a call the the manufacturer's technical help line. They will know what causes it on your particular appliance.

 

MtB

[koukouvagia]

I had exactly the same symptoms on this oven.

In my case it was solved by going back to the installation instructions. Where the gas pipe entered the bottom of the cabinet that the oven was fixed in I'd made quite a large opening - about six inches in diameter. The instruction specified IIRC one inch. Once I'd reduced the size of the hole the problem disappeared.

I'm not saying that I really understood why this worked, but work it did.

[Detling]

From a caravan web site the suggestion was to open the oven door for a few seconds after lighting for the flame to allow it to settle and then close the door. It has worked very well to date.

[Sea Dog]

'Flame lift' as it's called can be notoriously difficult to diagnose. Especially when intermittent as the OP describes. I suggest a call the the manufacturer's technical help line. They will know what causes it on your particular appliance.

 

MtB

 

Thanks for your suggestion Mike - and I now know what to call the problem when I ring!

 

I had exactly the same symptoms on this oven.

In my case it was solved by going back to the installation instructions. Where the gas pipe entered the bottom of the cabinet that the oven was fixed in I'd made quite a large opening - about six inches in diameter. The instruction specified IIRC one inch. Once I'd reduced the size of the hole the problem disappeared.

I'm not saying that I really understood why this worked, but work it did.

 

Thanks, good to hear you've sorted yours too. There's so much air space behing my cooker it could be freestanding, but I've sourced a pdf of the instructions from Thetford's website and I guess this is the hole you refer to...

 

The appliance MUST have a gas escape hole (min size Ø 25mm; max Ø50mm; or shaped hole

of equivalent area) in the floor, directly beneath the appliance

So, I've compromised and gone for a 35mm hole in the floor - does anyone have a 35mm bung thay can get to me really, really quickly??!!

From a caravan web site the suggestion was to open the oven door for a few seconds after lighting for the flame to allow it to settle and then close the door. It has worked very well to date.

 

Ah, that's certainly something to try first! I confess I always close the door right away.

[Dinz]

may sound a bit mad but is your gas cylinder nearly empty?

When doing my BSC the manometer was everywhere.

Cylinder on last dregs.

Switched to new one and all stabilized immediately.

When diff. on regulator drops off they can wander.

[MtB]

 

The appliance MUST have a gas escape hole (min size Ø 25mm; max Ø50mm; or shaped hole

of equivalent area) in the floor, directly beneath the appliance

 

 

That only applies when fitted in a caravan, and is to allow gas to escape in the event of a leak. I would not expect it to affect flame stability.

 

 

MtB

[Sea Dog]

may sound a bit mad but is your gas cylinder nearly empty?

 

Thanks, but I changed over to a new bottle recently and haven't noticed any change. Worth the thought though and puts another thing on the check list for anyone with the same issue reading this thread later.

 

 

That only applies when fitted in a caravan, and is to allow gas to escape in the event of a leak. I would not expect it to affect flame stability.

 

 

MtB

 

Thanks Mike, much appreciated. It was a professional install at Simon Piper so they'll have done a few, but nice to get these possibilities ticked off (and I didn't really drill the hole in the bottom so I don't need the bung)

[MtB]

 

Thanks Mike, much appreciated. It was a professional install at Simon Piper so they'll have done a few, but nice to get these possibilities ticked off (and I didn't really drill the hole in the bottom so I don't need the bung)

 

Ah but you may have done exactly as instructed and drill a hole in the floor, which is still 6" above the baseplate innit!

 

MtB

[Sea Dog]

 

Ah but you may have done exactly as instructed and drill a hole in the floor, which is still 6" above the baseplate innit!

 

MtB

 

True, but my notional drill was a gurt big long 'un! And who reads instructions until all else has failed?

[MtB]

 

True, but my notional drill was a gurt big long 'un! And who reads instructions until all else has failed?

 

 

Bloody useless, them notional drills. Get a Bosch.

 

MtB