I need your advice about the gas tank reducer

[guinacht]

Last year we bought a brand-new gas tank in Thailand for the new kitchen hob in our house.

And we bought a gas pressure reducer from the same shop.

The reducer is yellow color and has a button on it to start the gas flow.

We have a problem every time after we have filled the tank with LPG gas.

When the tank is full we are not able to start our gas hob, the gas is simply not being supplied to the hob.

Finally, after 20 minutes of trying to lit the gas we have it burning.

What can be wrong with this setup?

Wehave isolated the problem now to:

• Defective gas reducer
• Defective kitchen hob

Because the gas tank itself is no problem, we have tested it with another burner.

[Gsxrnz]

After fitting th reducer to the new (full) tank, fully opening the tank valve, and pushing the button on the reducer, do you hear a hissing at the hob when you turn the starter knob?

If so, that implies it's not a gas delivery problem, and the issue may be the starter on the hob.

If no hissing is heard (or smell of gas), then yes it sounds like the reducer has some issues.

Edited January 7, 2016 by Gsxrnz

[guinacht]

No, no hissing sound at all, even if we open full. And no smell of gas.

Do you know if the kitchen hobs have some kind of reducer built-in?

Edited January 7, 2016 by guinacht

[Gsxrnz]

No, but from what you're saying, eventually (after I assume playing with the reducer button and knobs etc), the gas delivery finally commences and you'll hear a hissing and smell the gas. This implies there is something wrong in the reducer that makes it untrustworthy, even when eventually something makes it work properly.

Nobody wants a faulty reducing valve in their house. I'd trash it and get a new one to be on the safe side.

[guinacht]

Yes, I do agree with you.

But my wife is reluctant to spend money on the new reducer.

She believes that probably the hob may be faulty.

Is there any chance of this?

[Crossy]

A new regulator will cost a few bucks, try it, it's a lot cheaper than a new hob.

We had one of the 'push to start' regulators and it had similar issues to our OP. I just bought an ordinary one from Tesco, cheapo Lucky-Flame brand, works first time every time.

[guinacht]

My brother in law is saying that the gas reducers come in different colors reflecting their capabilities.

Ours is yellow color. I have never seen a yellow reducer before.

Normally they come in red color, don't they?

What is the difference between the red one and the yellow one?

Does the color mean different output pressure?

[keeniau96]

We have three regulators, all for typical Fagor HOBs. All are red with a push button, all have been working for years with no problem.

[guinacht]

Here are the details of our kitchen hob.

This is เตาแก๊สฝัง TEKA รุ่น GS 73 2G AI AL 2TR

http://www.e-sarnbestbuy.com/product/552/เตาแก๊สฝัง-teka-รุ่น-gs-73-2g-ai-al-2tr

[guinacht]

And this is the gass pressure regulator we are using and suspecting to be faulty.

Lucky Flame L-325/S

http://www.luckyflame.co.th/l-325s.html

[guinacht]

This is another model of Lucky Flame gas pressure regulator.

This one comes in red color.

Lucky Flame LS-330L

http://www.luckyflame.co.th/ls-330l.html

[guinacht]

I have studied the technical specifications of both.

The output pressure is the same.

It means that the color of the regulator has nothing to do with the output pressure, and my brother in law was wrong.

The only difference between them is the Gas Flow Rate:

• The red one is capable of supplying gas at the maximum flow rate of 1.4 kilograms per hour
• The yellow one is capable of supplying gas at the maximum flow rate of 4.0 kilograms per hour

It means that the yellow one is about 3 times more powerful than the red one.

Edited January 8, 2016 by guinacht

[guinacht]

Today I asked my wife to call Lucky Flame company in Bangkok and ask them if we can use a red color regulator with our kitchen hob.

I don't know who was answering the phone but that was certainly a Lucky Flame employee on the phone.

My wife asked the question: "Can we use the red color regulator for our kitchen hob Teka GS 73 2G AI AL 2TR?".

The Lucky Flame employee answered: "No, you cannot. Because this may be dangerous."

Oh my God!

Why may it be dangerous?

I have asked my brother in law to find the old red color regulator we used to use 5 years ago with the large gas burner.

This regulator is Sun brand manufactured by Kritchai Machinery in Thailand.

So what do you think?

Can we use this red color regulator for our kitchen hob Teka GS 73 2G AI AL 2TR ?

[Gsxrnz]

You're over thinking the whole problem. Your regulator is buggered.

In the past, your current regulator has worked satisfactorily but whenever you change gas bottles it has problems until you push the button often enough, and then it works OK. I am assuming that when in use, it performs ok.

Obviously the regulator has issues. Replace the regulator with a new one of the same type. The lower output regulator is what you ideally need.

Problem solved.

While the red regulator you are quoting may have a far greater maximum output, the limiting factor is the device (hob or other device) that is attached to it. i.e your hob may only use 10% of the available gas volume when both burners are on full. But if the bottle was connected to a commercial hob with say 10 burners, it may need the higher output reducer to cope with the demand of those 10 burners.

Edited January 8, 2016 by Gsxrnz

[sipi]

Low pressure gas appliances (your hob) run at 2.75kPa. Your existing regulator is a low pressure regulator.

The cast iron ring burner looks to be a high pressure appliance, as does the red regulator.

If you hook a high pressure regulator up to a low pressure appliance, yes it is dangerous (as explained by Lucky Flame).

It seems from your OP that after 20 minutes the hob burns correctly so the regulator and appliance seem to be correctly matched.

The problem is only after filling/ changing the bottle. Are you sure you are not just purging the air from the system before the gas arrives at the appliance?

How long is the run from bottle to hob? 2.75kPa is not a lot of pressure and takes a little while to get through the system.

[guinacht]

Low pressure gas appliances (your hob) run at 2.75kPa. Your existing regulator is a low pressure regulator.

The cast iron ring burner looks to be a high pressure appliance, as does the red regulator.

If you hook a high pressure regulator up to a low pressure appliance, yes it is dangerous (as explained by Lucky Flame).

It seems from your OP that after 20 minutes the hob burns correctly so the regulator and appliance seem to be correctly matched.

The problem is only after filling/ changing the bottle. Are you sure you are not just purging the air from the system before the gas arrives at the appliance?

How long is the run from bottle to hob? 2.75kPa is not a lot of pressure and takes a little while to get through the system.

Yes, strangely the problem appears only after filling the bottle.

But if the gas tank is half empty this problem is disappearing.

What that can be?

[guinacht]

The run of the reinforced flexible plastic hose is about 2 meters.

Edited January 8, 2016 by guinacht

[sipi]

It does seem a problem with air getting in when the tank is changed, but I could be wrong.

If the cylinder is disconnected and replaced with a new one, then air gets into the lines and basically there is nothing you can do about it other than purge it out through the hob which is what you are doing. 20 minutes to purge 2 mtrs of line does seem a little long though.

I was a gas-fitter years ago and this is all I can put it down to.

[guinacht]

It does seem a problem with air getting in when the tank is changed, but I could be wrong.

If the cylinder is disconnected and replaced with a new one, then air gets into the lines and basically there is nothing you can do about it other than purge it out through the hob which is what you are doing. 20 minutes to purge 2 mtrs of line does seem a little long though.

I was a gas-fitter years ago and this is all I can put it down to.

I'm sorry, I underestimated the length of the hose.

The run is in fact 3 meters!

[guinacht]

You're over thinking the whole problem. Your regulator is buggered.

In the past, your current regulator has worked satisfactorily but whenever you change gas bottles it has problems until you push the button often enough, and then it works OK. I am assuming that when in use, it performs ok.

Obviously the regulator has issues. Replace the regulator with a new one of the same type. The lower output regulator is what you ideally need.

Problem solved.

While the red regulator you are quoting may have a far greater maximum output, the limiting factor is the device (hob or other device) that is attached to it. i.e your hob may only use 10% of the available gas volume when both burners are on full. But if the bottle was connected to a commercial hob with say 10 burners, it may need the higher output reducer to cope with the demand of those 10 burners.

Is it a good idea to use a regulator without push-button?

[sipi]

Ok I am giving my age away here, but "push-button" regulators weren't invented when I was working in the field. I can only assume that they are a bypass/ purge mechanism. It just looks like one more thing that can leak or go wrong. I will agree with Crossy that for a few hundred baht it might be worth changing.

If you have a blue flame and can't smell gas when the hob is running then you can safely assume that all is well without the hassle of attaching manometers or the like. It will take a while for a 3 mtr line to purge. That is about the length of a gas run on a large caravan and they take a while to expel the air.

[Crossy]

Just to add to the mix, our Lucky Flame reg is green, 4kg / hr (no button). It's running a 3 ring Hafele hob just fine and has been for 4 years now. We have only about 1m of pipe, hob lights after a few seconds after changing the bottle.

No issues with not having the button, it's there as a safety device so you can't open the bottle into an already turned on hob, it's an extra reminder.

[guinacht]

Just to add to the mix, our Lucky Flame reg is green, 4kg / hr (no button). It's running a 3 ring Hafele hob just fine and has been for 4 years now. We have only about 1m of pipe, hob lights after a few seconds after changing the bottle.

No issues with not having the button, it's there as a safety device so you can't open the bottle into an already turned on hob, it's an extra reminder.

Yes, safety is always a good thing.

But this push-button may be another bottleneck and the source of unexpected issues, what do you think?

Edited January 8, 2016 by guinacht

[Crossy]

We have no button, never a problem but it's only ever me or Wifey's son that changes the bottle.

[longball53098]

Just to add to the mix.

I have a Lucky Flame Push-button Safety regulator. Been using it for over 6 years now with no issues that I know of. Sometimes we need to push(reset) the button to get gas flowing after a bottle change. I do not pay attention to when this occurs. I do know that when the button is pressed in that a distinct click is felt implying the regulator valve is now reset.

My regulator is sort of a lime green in color