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Finding cause of low heat How to find cause of low pressure, low heat, small or no flames

#1 User is offline   takeahike66 

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Posted 18 August 2006 - 10:38 PM

Looking for cause of low pressure, low heat, small or no flames????
Many posters on this forum have posted various types of questions of why their grill are not heating up properly. Here are some of the steps that I would take to find the cause.

This assumes that you do have gas in the tank. Also if this is a new tank, you should have purged the tank before filling.

Check to make sure there is no sharp bend in the hose from the tank to grill.
My tank must be position where the hose attaches to the tank must be in the 2:00 o’clock position, otherwise the hose is bent sharply, therefore reducing the gas flow.

TANK SAFETY VALVE RESET

From experience, I observed this condition that the tank safety valve had tripped.
1- After lighting the first burner, the flames were very low and took a while to completely light on both side.
2- Turning the knob had no affect on the flame size
3- Other burners were difficult to light or or when the valve was open the lit burner flame became smaller

How to reset tank safety valve.
- Remove the grates and tamers (to watch the flames).
- make sure all burners and the gas tank valve is off
- Open and close a grill burner valve
- Disconnect the hose from the tank

Once the safety valve has tripped, you have to disconnect the hose for it to reset

- reconnect the hose back to the tank

Tank valve should now be reset.

- Slowly open the tank valve 2 full turns
Note: the reason for only opening the gas value 2 full turns is that I found out that some OPA safety valve would trip if the gas valve was open too much. Once you know that it can operate with the valve open fully during startup, feel free to do so.

Light the first burner.
With the JennAir, you must press in the knob, and continue to <B>press in</B> the knob while turning it past the ignition point.
I normally continue to press it in for a few seconds after it lights. This will give it a little extra gas during ignition.

Continue to light the other burners using the procedure above.

Observe the flames.

This photo posted by another member shows how long the flames should be and the color.
About 1 " long, all blue, or blue with yellow tips.

[attachment=574:attachment]

If your flames are not at least 1" or more long, then this is an indication that the gas pressure is low or there is a blockage somewhere.

Since the tank valve has already been reset,

If the hose is ok and the safety valve is reset, then I would suspect blockage in the burners.
I would take the burners out, inspect the throat for dead insects, spider webs, wasp nest, etc.

Also blow out the burners with compress air and make sure they are free flowing out through the burner holes. I'm surprise at how much particles are blown out of the burners. (take them to a gas station and use the air hose, you will have to have an adapter, purchased at an auto part store)

Inconsistent flame may indicate that some of the holes are blocked and the burners need cleaning (like the ones in the photo).

----------------------------------------------------------------------------
If the tank valve has been reset, the hose is not pinched or no sharp bends, and no blockage to the burner, then it might be the regulator.
The only way I know how to pinpoint a problem with a regulator is to try another one. I would call Customer service, tell them the problem, and all the actions taken to resolve the issue. You should be able to get a new one from them free.

All of this is based on that all the burners are receiving little gas or no gas.

The other question is: Does the rotisserie burner light or the side burner work ok. If these work, then I would suspect the line to the main burners. If only one burner is not working right, it's either the valve or the one burner. Try swapping the burners around and see if the problem follows the burner.

If the problem does not follow the burner when swapped, then the valve is defective or there is a blockage between the valve and the burner.

If everything is working normally, flames are fairly consistent, but the heat produce by your grill just doesn't seem adequate, you could check to see what the pressure you are receiving at the grill either from the tank or your natural gas line.

Home-Made Manometer


If the output pressure is too low based on the rating for your grill, you might consider replacing the normal low pressure regulator with an adjustable two stage <b> low-pressure </b> regulator. This will give about a 15% boost in pressure.

Two-stage regulator mod

Hope this helps.

Below is additional information on the new safety valve on LP tanks.

NEW TANK - When you have a new cylinder filled for the first time, make sure your LP supplier purges your
new cylinder of trapped air. Otherwise, an improper mixture of gas and air will make it impossible to light
your LP appliances.

SAFETY VALVE ON NEW LP CYLINDERS - New LP cylinders are equipped with the Type 1 ACME valve. This valve has an internal spring-loaded module that will not allow gas to flow from the cylinder until a positive seals has been made at the connection. A Type 1 ACME Connector or QCC-1 (identifiable by the large green nut) should be used.
The QCC-1 connection requires no wrenches to install and has right-hand threads. The nipple has a patented Flow Limiting Device that shuts off gas flow if a leak occurs between the regulator and the appliance burner valve. It activates each time you open the cylinder valve, so be sure the appliance is turned OFF before you open the valve. If the appliance is not turned OFF (or there is a leak in the line) when you open the valve, the Flow Limiting Device will not be able to reset and will restrict gas flow to the appliance.
The QCC-1 connector is also heat sensitive, shutting off the flow of gas if it is exposed to temperatures
between 240 & 300 degrees F.

When purging a new tank equipped with the Type 1 ACME cylinder valve, a POL device must be used to allow the air from the cylinder to escape.

The new style safety valves also have an excess flow safety feature built into them. The purpose of the excess flow is to limit the amount of propane that will be allowed to escape from the tank in the event of a rupture or severance of the propane hose or gas line. Sometimes, this excess flow can shut down the valve if the grill valve has been turned on before the valve on the tank has been turned on. The excess flow
senses something is wrong and limits the flow of propane.

Hopes this provides some help to analyzing your problems with low heat.
Takeahike66
---------------------------------------------------
JennAir - 720-150LP - 5 burner, Sep 05
Ultra-Sear Portable IR Grill Nov 07
Char Broil Big Easy Oiless Fryer
Masterbuilt Electric Smoker WTFA brand, Nov 08
---------------------------------------------------

----- Accessories -----
- Sears SS Island end modules (2) - BBQ Grillware LED Grill Lights (2)
- JennAir Rotisserie w/ extra splits - E-Z Que Rotisserie 8"
- Maverick ET-72 Remote probe - Maverick OT-03 Oven Thermometer for smoking

----- Modifications -----
- Utensil hooks (10) - Remove built-in smoker box
- Hood ventilation Gap Covers - Wok Holder for side burner
- Sunshine Griddle - Customized SS grates to fit Sunshine Griddle
- Custom fitted center divider mod - Marshall two-stage regulator
- Fitted Manometer in gas line - Custom smoking rack (Shelly design)
- Rotisserie storage using existing back bolts, also used to store warming rack & grate
0

#2 User is offline   athomas 

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Posted 04 September 2006 - 06:35 AM

We have a new Jenn-air 18852 and have had problems with it heating up above 300 - is that pretty common with this model? We'll try the steps you gave below, but wanted to check if this was normal and what experience anyone else has had with this model.



View Posttakeahike66, on Aug 18 2006, 11:38 PM, said:

Looking for cause of low pressure, low heat, small or no flames????
Many posters on this forum have posted various types of questions of why their grill are not heating up properly. Here are some of the steps that I would take to find the cause.

This assumes that you do have gas in the tank. Also if this is a new tank, you should have purged the tank before filling.

Check to make sure there is no sharp bend in the hose from the tank to grill.
My tank must be position where the hose attaches to the tank must be in the 2:00 o’clock position, otherwise the hose is kinked, therefore reducing the gas flow.
How to reset tank safety valve.
- Remove the grates and tamers (to watch the flames).
- make sure all burners and the gas tank valve is off
- Open and close a grill burner valve
- Disconnect the hose from the tank

- reconnect the hose back to the tank

Tank valve should now be reset.

- Open the tank valve 2 full turns
Note: the reason for only opening the gas value 2 full turns is that I found out that some OPA safety valve would trip if the gas valve was open too much. Once you know that it can operate with the valve open fully, feel free to do so.

Light the first burner.
With the JennAir, you must press in the knob, and continue to <B>press in</B> the knob while turning it past the ignition point.
I normally continue to press it in a split second after it lights. This will give it a little extra gas during ignition.

Continue to light the other burners using the procedure above.

Observe the flames.

This photo posted by another member shows how long the flames should be and the color.
About 1 " long, all blue, or blue with yellow tips.

Attachment attachment

If your flames are not at least 1" or more long, then this is an indication that the gas pressure is low or there is a blockage somewhere.

Since the tank valve has already been reset,

If the hose is ok and the safety valve is reset, then I would suspect blockage in the burners.
I would take the burners out, inspect the throat for dead insects, spider webs, wasp nest, etc.

Also blow out the burners with compress air and make sure they are free flowing out through the burner holes. I'm surprise at how much particles are blown out of the burners. (take them to a gas station and use the air hose, you will have to have an adapter, purchased at an auto part store)

Inconsistent flame may indicate that some of the holes are blocked and the burners need cleaning (like the ones in the photo).

----------------------------------------------------------------------------
If the tank valve has been reset, the hose is not pinched, and no blockage to the burner, then it might be the regulator.
The only way I know how to pinpoint a problem with a regulator is to try another one. I would call Customer service, tell them the problem, and all the actions taken to resolve the issue. You should be able to get a new one from them free.

All of this is based on if all the burners all receiving little gas or no gas.

The other question is: Does the rotisserie burner light or the side burner work ok. If these work, then I would suspect the line to the main burners. If only one burner is not working right, it's either the valve or the one burner. Try swapping the burners around and see if the problem follows the burner.

If everything is working normally? Flames are fairly consistent, but heat produce by your grill just doesn't seem adequate, You could check to see what the pressure you are receiving at the grill either from the tank or your natural gas line.

Home-Made Manometer
If the output pressure is too low based on the rating for your grill, you might consider replacing the normal low pressure regulator with an adjustable two stage <b> low-pressure </b> regulator. This will give about a 15% boost in pressure.

Two-stage regulator mod

Hope this helps.

Below is additional information on the new safety valve on LP tanks.

NEW TANK - When you have a new cylinder filled for the first time, make sure your LP supplier purges your
new cylinder of trapped air. Otherwise, an improper mixture of gas and air will make it impossible to light
your LP appliances.

SAFETY VALVE ON NEW LP CYLINDERS - New LP cylinders are equipped with the Type 1 ACME valve. This valve has an internal
spring-loaded module that will not allow gas to flow from the cylinder until a positive seals has been made
at the connection. A Type 1 ACME Connector or QCC-1 (identifiable by the large green nut) should be used.
The QCC-1 connection requires no wrenches to install and has right-hand threads. The nipple has a patented Flow Limiting Device that shuts off gas flow if a leak occurs
between the regulator and the appliance burner valve. It activates each time you open the cylinder valve,
so be sure the appliance is turned OFF before you open the valve. If the appliance is not turned OFF (or there is a leak in the line) when you
open the valve, the Flow Limiting Device will not be able to reset and will restrict gas flow to the appliance.
The QCC-1 connector is also heat sensitive, shutting off the flow of gas if it is exposed to temperatures
between 240 & 300 degrees F.

When purging a new tank equipped with the Type 1 ACME cylinder valve, a POL device must be used to allow the air from the cylinder to
escape.

The new style safety valves also have an excess flow safety feature built into them. The purpose of the excess flow is to limit the amount of propane that will be allowed to escape from the tank
in the event of a rupture or severance of the propane hose or gas line. Sometimes, this excess flow can plug
shut if the grill valve has been turned on before the valve on the tank has been turned on. The excess flow
senses something is wrong and limits the flow of propane.

0

#3 User is offline   Eric D 

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  • Interests:
    Things I like and have interest in are: Grilling with my Jen-air 720-0061-LP grill. Smoking all types of meat on my Great Outdoors LP smoker unit for family and friends. I like working on and flying aircraft, fixed wing and rotor wing. The best dog for me is a Doberman.<br /><br />I have fun here, at the BBQ Source Forums with all the great grilling, smoking and cooking, plus all the great people.

Posted 04 September 2006 - 07:44 AM

View Postathomas, on Sep 4 2006, 07:35 AM, said:

We have a new Jenn-air 18852 and have had problems with it heating up above 300 - is that pretty common with this model? We'll try the steps you gave below, but wanted to check if this was normal and what experience anyone else has had with this model.
Hi Athomas,

No, 300 is not normal for full heat. In fact, you really can't do much at all as far as grilling goes with that low of a temp. I do not recognize your model number. Could you explain a little more on what model you have. The number of burners, what type of fuel (LP or NG) and what year it is? Somewhere on the grill there should be a model number that starts with 720- . Did you purchase it from Lowes?

I'm sure we can help out with the low heat issue. I'm happy you found us here at the BBQ Source Forums.

Regards,

Eric D :D
Grilling and cooking for friends and family is one of life's most treasured gifts!
BBQSource Forums
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#4 User is offline   takeahike66 

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Posted 05 September 2006 - 02:15 AM

View Postathomas, on Sep 4 2006, 04:35 AM, said:

We have a new Jenn-air 18852 and have had problems with it heating up above 300 - is that pretty common with this model? We'll try the steps you gave below, but wanted to check if this was normal and what experience anyone else has had with this model.


Hi Athomas- Welcome.

The Lowes Item number you quoted appears to be the JennAir 3 burners with 15K bTU burners. These are hotter than the normal 13K burners, so you should be reaching tems above 600 700 degress on the Hood therm. I am guessing that it is the LP model and not the NG model. I would make sure you don't have a hose that is bented too sharply, and that the safety valve is reset by disconnecting and reconnecting the hose/regulator per the instructions. If the rotisserie burner doesn't fire up nice and red, You have a gas flow problem.

Check and make sure the flames are at least 3/4 to 1" in length.
Takeahike66
---------------------------------------------------
JennAir - 720-150LP - 5 burner, Sep 05
Ultra-Sear Portable IR Grill Nov 07
Char Broil Big Easy Oiless Fryer
Masterbuilt Electric Smoker WTFA brand, Nov 08
---------------------------------------------------

----- Accessories -----
- Sears SS Island end modules (2) - BBQ Grillware LED Grill Lights (2)
- JennAir Rotisserie w/ extra splits - E-Z Que Rotisserie 8"
- Maverick ET-72 Remote probe - Maverick OT-03 Oven Thermometer for smoking

----- Modifications -----
- Utensil hooks (10) - Remove built-in smoker box
- Hood ventilation Gap Covers - Wok Holder for side burner
- Sunshine Griddle - Customized SS grates to fit Sunshine Griddle
- Custom fitted center divider mod - Marshall two-stage regulator
- Fitted Manometer in gas line - Custom smoking rack (Shelly design)
- Rotisserie storage using existing back bolts, also used to store warming rack & grate
0

#5 User is offline   jeremyp777 

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Posted 19 April 2010 - 01:38 PM

Thanks so much, Takeahike66! You saved my butt. I was about to buy a new regulator and when I read your article I found that my safety valve was tripping because I had the gas valve open too much! I've been trying to figure out what was wrong with it since last summer, when I would be able to turn on 1 to 2 of the burners and they would work full blast. But when I would turn on the 3rd or 4th burner, they would all go out or barely have any flame at all. I'm not sure why it used to work with the valve all the way open when it was newer, but maybe the safety valve isn't as forgiving as it used to be. Thanks again for taking the time to write the Article!

JeremyP777
Perfect Flame 2518SL-LPG http://bbq.about.com...aapr030407c.htm

View Posttakeahike66, on Aug 18 2006, 07:38 PM, said:

for cause of low pressure, low heat, small or no flames????
Many posters on this forum have posted various types of questions of why their grill are not heating up properly. Here are some of the steps that I would take to find the cause.

This assumes that you do have gas in the tank. Also if this is a new tank, you should have purged the tank before filling.

Check to make sure there is no sharp bend in the hose from the tank to grill.
My tank must be position where the hose attaches to the tank must be in the 2:00 o’clock position, otherwise the hose is bent sharply, therefore reducing the gas flow.

TANK SAFETY VALVE RESET

From experience, I observed this condition that the tank safety valve had tripped.
1- After lighting the first burner, the flames were very low and took a while to completely light on both side.
2- Turning the knob had no affect on the flame size
3- Other burners were difficult to light or or when the valve was open the lit burner flame became smaller

How to reset tank safety valve.
- Remove the grates and tamers (to watch the flames).
- make sure all burners and the gas tank valve is off
- Open and close a grill burner valve
- Disconnect the hose from the tank

Once the safety valve has tripped, you have to disconnect the hose for it to reset

- reconnect the hose back to the tank

Tank valve should now be reset.

- Slowly open the tank valve 2 full turns
Note: the reason for only opening the gas value 2 full turns is that I found out that some OPA safety valve would trip if the gas valve was open too much. Once you know that it can operate with the valve open fully during startup, feel free to do so.

Light the first burner.
With the JennAir, you must press in the knob, and continue to <B>press in</B> the knob while turning it past the ignition point.
I normally continue to press it in for a few seconds after it lights. This will give it a little extra gas during ignition.

Continue to light the other burners using the procedure above.

Observe the flames.

This photo posted by another member shows how long the flames should be and the color.
About 1 " long, all blue, or blue with yellow tips.

Attachment attachment

If your flames are not at least 1" or more long, then this is an indication that the gas pressure is low or there is a blockage somewhere.

Since the tank valve has already been reset,

If the hose is ok and the safety valve is reset, then I would suspect blockage in the burners.
I would take the burners out, inspect the throat for dead insects, spider webs, wasp nest, etc.

Also blow out the burners with compress air and make sure they are free flowing out through the burner holes. I'm surprise at how much particles are blown out of the burners. (take them to a gas station and use the air hose, you will have to have an adapter, purchased at an auto part store)

Inconsistent flame may indicate that some of the holes are blocked and the burners need cleaning (like the ones in the photo).

----------------------------------------------------------------------------
If the tank valve has been reset, the hose is not pinched or no sharp bends, and no blockage to the burner, then it might be the regulator.
The only way I know how to pinpoint a problem with a regulator is to try another one. I would call Customer service, tell them the problem, and all the actions taken to resolve the issue. You should be able to get a new one from them free.

All of this is based on that all the burners are receiving little gas or no gas.

The other question is: Does the rotisserie burner light or the side burner work ok. If these work, then I would suspect the line to the main burners. If only one burner is not working right, it's either the valve or the one burner. Try swapping the burners around and see if the problem follows the burner.

If the problem does not follow the burner when swapped, then the valve is defective or there is a blockage between the valve and the burner.

If everything is working normally, flames are fairly consistent, but the heat produce by your grill just doesn't seem adequate, you could check to see what the pressure you are receiving at the grill either from the tank or your natural gas line.

Home-Made Manometer


If the output pressure is too low based on the rating for your grill, you might consider replacing the normal low pressure regulator with an adjustable two stage <b> low-pressure </b> regulator. This will give about a 15% boost in pressure.

Two-stage regulator mod

Hope this helps.

Below is additional information on the new safety valve on LP tanks.

NEW TANK - When you have a new cylinder filled for the first time, make sure your LP supplier purges your
new cylinder of trapped air. Otherwise, an improper mixture of gas and air will make it impossible to light
your LP appliances.

SAFETY VALVE ON NEW LP CYLINDERS - New LP cylinders are equipped with the Type 1 ACME valve. This valve has an internal spring-loaded module that will not allow gas to flow from the cylinder until a positive seals has been made at the connection. A Type 1 ACME Connector or QCC-1 (identifiable by the large green nut) should be used.
The QCC-1 connection requires no wrenches to install and has right-hand threads. The nipple has a patented Flow Limiting Device that shuts off gas flow if a leak occurs between the regulator and the appliance burner valve. It activates each time you open the cylinder valve, so be sure the appliance is turned OFF before you open the valve. If the appliance is not turned OFF (or there is a leak in the line) when you open the valve, the Flow Limiting Device will not be able to reset and will restrict gas flow to the appliance.
The QCC-1 connector is also heat sensitive, shutting off the flow of gas if it is exposed to temperatures
between 240 & 300 degrees F.

When purging a new tank equipped with the Type 1 ACME cylinder valve, a POL device must be used to allow the air from the cylinder to escape.

The new style safety valves also have an excess flow safety feature built into them. The purpose of the excess flow is to limit the amount of propane that will be allowed to escape from the tank in the event of a rupture or severance of the propane hose or gas line. Sometimes, this excess flow can shut down the valve if the grill valve has been turned on before the valve on the tank has been turned on. The excess flow
senses something is wrong and limits the flow of propane.

Hopes this provides some help to analyzing your problems with low heat.

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