Gas and Oil Home Heating Furnaces - FYI: Delayed Ignition. Causes, Effects and Remedies
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Sharp Advice
11-04-01, 06:06 PM
FYI: Delayed Ignition
Causes, Effects and Remedies
POST NO REPLIES!
Posting Date: 11-04-01
"Delayed Ignition" in an appliance can be best discribed as a loud bang or explosion sound. Delayed ignition can happen to almost any gas appliance that has a firebox or heat exchanger.
Delayed ignition is a condition that happens, most often, to home heating appliances when the heater is first firing up. Heating appliances are more prone to delayed ignition because they remain unused for several months during the summer season, the fireboxes help to contain the moisture caused by ambient temperature changes and during the burning of either propane or natural gas.
Delayed ignition also happens to boilers, pool and spa heaters. These types of high btu capacity and high gas consumption heaters, having delayed ignition due to a lack of useage and other conditions, can be extremely dangerous. Always remain clear of this type of appliance when first turning it on, after any long duration time period of non useage.
Delayed ignition also happens in ovens and water heaters. These two appliances are prone to having there burners ignition ports becoming restricted or clogged from sulfur and debris of many types. Water heater debris is most often from scale and rust of the steel the tank is made from, while ovens caused by sulfur deposits and warped burner cross-over ports.
Some furnace and other heating appliance burners are made from cast iron or steel, which is highly prone to corrode. The corrosion then restricts or clogs the ports {Holes or Slots in the burners} preventing ignition to other burners across and down the line, in the secession of lighting. Lint and dust, however, are the most commonly found causes for pilot and burner port restrictions.
Sulfur deposits may also be a contributing factor to restricting a burner or pilot flame causing delayed ignition. Sulfur is a commonly found compound ingredient in natural gas. Some natural gas well sources have little sulfur while other well sources have higher amounts. Therefore, some parts of the country may be more prone to find sulfur deposits accumulated on the burners and pilots of natural gas appliances then other parts of the country.
Sulfur deposits found on pilots and burners can be identified by the white powdery substance that collects in the area of the burners ignition prots and pilot assemblies.
Clearing the effected restricted ports usually solves the "Delayed Ignition" problem. Providing they are clogged or restricted. Which is not always the case.
Some appliances use aluminum or stainless steel burners, which can also become restricted or clogged by lint, dust, minor corrosion and sulfur deposits. Usually these types of burners use slots called "RIBBONS."
The burners are called "Ribbon Burners" because the burner ports are not round holes. They are two pieces of metal joined together with corrugated edges. The upper side of these types of burners have the Ribbon corrugations. These types of burners are often found to be restricted with rust and or scale deposits from the firebox.
Older furnaces or heaters, of any type, using either propane or natural gas fuels may use burners made of iron. These types are very prone to metal rust and corrosion. Clearing out the slots or holes and removing the loose rust on the burners solves the delayed ignition problem.
Not all delayed ignition problems are caused by the above mentioned possibilities. Some delayed ignition problems occur when one or more burner orifices become clogged or restricted with excessive lint, dust or with tiny "SPIDERS."
Restrictions caused by "SPIDERS" will have the same type of "Delayed Ignition" effect. Usually the effected burner will not even display flames or have flames visibly much smaller then others. Visibly noticeable burner flame size is an ideal method of determining the effected burners.
Spiders can and often do effect pilot flames. Usually the flame appears {can be seen} but may burn yellow or be rather tiny in size, as compared to the normal size. In this case, the pilots orifice must be removed and the spider or other obstruction cleared.
The effected burner that fails to light or a burners flames which are too small, when compared with the other burners in multi-burner appliances, the effected burner will fail to light the next burner in the secession of lighting. The effected burner or burners can be the result of a spider restricting or clogging the burners orifice. This condition can also be causing the delayed ignition problem. The result will be the same. The sound of an explosion.
The closer the restricted burner is to the pilot in multi-burner appliances and the number of burners there is in total, can determine how severe the delayed ignition can be. However, the condition can happen to any appliance regardless of the number of burners.
Yellow pilot flames, causing delayed ignition, can also be caused by lint and dust restricting the pilots air intake holes. The air intake holes for pilots are usually located just behind the flame, often located in the pilot tubing assembly just behind the flame, in the locking nut that secures the pilot gas tubing to the pilot assembly housing or in the pilot assembly body itself. Clearing these air inlet holes of debris and sulfur deposits etc. usually solves the yellow flame problem.
Delayed ignition can happen to any gas appliance left unused for long periods of time. Such appliances can be found in vacant houses, recreational vehicles, vacation homes, cabins, etc.
Additionally, any appliance that has a rusted burner or firebox. Incorrectly adjusted pilot flame, incorrectly sized burner flames, incorrect gas pressure, defective pilot or burner parts, etc.
Delayed ignition can be a serious problem to any effected appliance. Delayed ignition, left uncorrected can damage the firebox, the appliance and the venting system. Uncorrected, both major and minor forms of delayed ignition can also be a hazardous condition to people and property. It must be corrected immediately.
Depending upon several factors, the type of effected appliance, the ability of a person to clearly identify the condition, poses the skills, tools, knowledge and experience to correct the condition, should not attempt to do so. The condition may need the special attention of a skilled and qualified service person.
Caution and Summation:
Any appliance left unused for extended periods of time, is located outdoors, in basements or attics, has metal or cast iron burners, is an older model appliance or is in poor working operation and or has been recently fixed, reassembled after a repair, moved and or modified, is prone to have a delayed ignition condition.
Delayed ignition conditions can cause serious flash burns and personal injury to persons, damage to the appliance and or property damage and fires.
Suggestion:
Select "Printable Version."
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Regards,
Gas Appliances Forum Moderator
Tom_Bartco
Energy Conservation Consultant & Natural Gas Appliance Diagnostics Technician.
Causes, Effects and Remedies
POST NO REPLIES!
Posting Date: 11-04-01
"Delayed Ignition" in an appliance can be best discribed as a loud bang or explosion sound. Delayed ignition can happen to almost any gas appliance that has a firebox or heat exchanger.
Delayed ignition is a condition that happens, most often, to home heating appliances when the heater is first firing up. Heating appliances are more prone to delayed ignition because they remain unused for several months during the summer season, the fireboxes help to contain the moisture caused by ambient temperature changes and during the burning of either propane or natural gas.
Delayed ignition also happens to boilers, pool and spa heaters. These types of high btu capacity and high gas consumption heaters, having delayed ignition due to a lack of useage and other conditions, can be extremely dangerous. Always remain clear of this type of appliance when first turning it on, after any long duration time period of non useage.
Delayed ignition also happens in ovens and water heaters. These two appliances are prone to having there burners ignition ports becoming restricted or clogged from sulfur and debris of many types. Water heater debris is most often from scale and rust of the steel the tank is made from, while ovens caused by sulfur deposits and warped burner cross-over ports.
Some furnace and other heating appliance burners are made from cast iron or steel, which is highly prone to corrode. The corrosion then restricts or clogs the ports {Holes or Slots in the burners} preventing ignition to other burners across and down the line, in the secession of lighting. Lint and dust, however, are the most commonly found causes for pilot and burner port restrictions.
Sulfur deposits may also be a contributing factor to restricting a burner or pilot flame causing delayed ignition. Sulfur is a commonly found compound ingredient in natural gas. Some natural gas well sources have little sulfur while other well sources have higher amounts. Therefore, some parts of the country may be more prone to find sulfur deposits accumulated on the burners and pilots of natural gas appliances then other parts of the country.
Sulfur deposits found on pilots and burners can be identified by the white powdery substance that collects in the area of the burners ignition prots and pilot assemblies.
Clearing the effected restricted ports usually solves the "Delayed Ignition" problem. Providing they are clogged or restricted. Which is not always the case.
Some appliances use aluminum or stainless steel burners, which can also become restricted or clogged by lint, dust, minor corrosion and sulfur deposits. Usually these types of burners use slots called "RIBBONS."
The burners are called "Ribbon Burners" because the burner ports are not round holes. They are two pieces of metal joined together with corrugated edges. The upper side of these types of burners have the Ribbon corrugations. These types of burners are often found to be restricted with rust and or scale deposits from the firebox.
Older furnaces or heaters, of any type, using either propane or natural gas fuels may use burners made of iron. These types are very prone to metal rust and corrosion. Clearing out the slots or holes and removing the loose rust on the burners solves the delayed ignition problem.
Not all delayed ignition problems are caused by the above mentioned possibilities. Some delayed ignition problems occur when one or more burner orifices become clogged or restricted with excessive lint, dust or with tiny "SPIDERS."
Restrictions caused by "SPIDERS" will have the same type of "Delayed Ignition" effect. Usually the effected burner will not even display flames or have flames visibly much smaller then others. Visibly noticeable burner flame size is an ideal method of determining the effected burners.
Spiders can and often do effect pilot flames. Usually the flame appears {can be seen} but may burn yellow or be rather tiny in size, as compared to the normal size. In this case, the pilots orifice must be removed and the spider or other obstruction cleared.
The effected burner that fails to light or a burners flames which are too small, when compared with the other burners in multi-burner appliances, the effected burner will fail to light the next burner in the secession of lighting. The effected burner or burners can be the result of a spider restricting or clogging the burners orifice. This condition can also be causing the delayed ignition problem. The result will be the same. The sound of an explosion.
The closer the restricted burner is to the pilot in multi-burner appliances and the number of burners there is in total, can determine how severe the delayed ignition can be. However, the condition can happen to any appliance regardless of the number of burners.
Yellow pilot flames, causing delayed ignition, can also be caused by lint and dust restricting the pilots air intake holes. The air intake holes for pilots are usually located just behind the flame, often located in the pilot tubing assembly just behind the flame, in the locking nut that secures the pilot gas tubing to the pilot assembly housing or in the pilot assembly body itself. Clearing these air inlet holes of debris and sulfur deposits etc. usually solves the yellow flame problem.
Delayed ignition can happen to any gas appliance left unused for long periods of time. Such appliances can be found in vacant houses, recreational vehicles, vacation homes, cabins, etc.
Additionally, any appliance that has a rusted burner or firebox. Incorrectly adjusted pilot flame, incorrectly sized burner flames, incorrect gas pressure, defective pilot or burner parts, etc.
Delayed ignition can be a serious problem to any effected appliance. Delayed ignition, left uncorrected can damage the firebox, the appliance and the venting system. Uncorrected, both major and minor forms of delayed ignition can also be a hazardous condition to people and property. It must be corrected immediately.
Depending upon several factors, the type of effected appliance, the ability of a person to clearly identify the condition, poses the skills, tools, knowledge and experience to correct the condition, should not attempt to do so. The condition may need the special attention of a skilled and qualified service person.
Caution and Summation:
Any appliance left unused for extended periods of time, is located outdoors, in basements or attics, has metal or cast iron burners, is an older model appliance or is in poor working operation and or has been recently fixed, reassembled after a repair, moved and or modified, is prone to have a delayed ignition condition.
Delayed ignition conditions can cause serious flash burns and personal injury to persons, damage to the appliance and or property damage and fires.
Suggestion:
Select "Printable Version."
Print and Save......:D
Regards,
Gas Appliances Forum Moderator
Tom_Bartco
Energy Conservation Consultant & Natural Gas Appliance Diagnostics Technician.