How a Gas Log Safety Pilot Works
and how to light a gas log safety pilot.
For details about gas log burners read: Gas Log Burners and Safety Pilot Controls
How does a gas log safety pilot work?
Aside from the electronic ignition systems, the basic premise for the safety pilots used on gas logs is the same as those used for decades with wall heaters,
hot water heaters, and nameless other gas appliances.
How do you light a gas log safety pilot?
You turn the control knob to the pilot position, push the knob in, light the pilot with a match, then hold the knob down for 30 seconds or so until the pilot stays lit by itself. Once the pilot light
will stay lit on its own, you can then move the knob to the "On" position. For manually operated gas logs such as the one pictured to the right, this will turn the logs on. For remote controlled
gas logs, this will put the valve in the necessary position for the remote control to actuate the burner.
What if the pilot will not stay lit?
If you cannot get the pilot to light at all, meaning you hold the button down in the pilot position and hold a match up to the pilot and nothing happens,
then either the valve is bad or something is abstructing the gas from coming into or going through the valve. If you can get the pilot to light with a match, but it will not stay
lit on its own after holding down the knob for 30 seconds, then put the knob back into the off position, wait 5 minutes and try again. If it still will not light, then something is definately wrong and
you should have a professional check it out.
This page is not meant to be a trouble-shooting guide for gas logs, but in general, if you cannot get your safety pilot to stay lit, It could be that the pilot flame needs adjustment, the
thermocouple has gone bad and needs to be replaced, the entire valve has overheated and must be replaced, or something is abstructing the gas line. In any case, it is probably time to seek the assistance
of a professional. Any plumber or heating and air conditioning service man who deals with gas appliances with a safety pilot should be able to help you.
How does a safety pilot actually work?
Although most of us have learned how to light one of these things at some time or other, few of us have any idea as to how this ingenious little safety system actually works.
So here is a brief, but hopefully useful explanation of how gas log safety pilots work so you can decide if it is something that you want or need. You may also find this information
helpful for any other device that has a similar safety pilot.
Gas Logs that have a safety pilot have a valve body that is attached directly to the burner. This valve body that has 2 separate valves inside that control the gas:
The valve to the main burner and the valve to the pilot flame.
When the pilot is lit, the flame directly hits what is called a thermocouple (or thermopile).
The thermocouple is the ingenious device that makes the whole system work. The physical properties of the thermocouple are such that it actually generates electricity when there is a great
enough difference in temparature between the tip of the thermocouple and the base.
If the pilot flame is too hot, then the entire thermocouple gets hot and there is not enough temperature difference to create a current. If the pilot
flame is too low or not coming into direct contact with the thermocouple (or simply blown out), then there is not enough heat to generate a current.
This is why the proper adjustment of the pilot flame is necessary for gas appliances that have a safety pilot.
Now, on to how the pilot system works.
The electricity from the thermocouple is used to power an electromagnet that holds the pilot valve open, thus allowing the pilot to stay lit by itself. The amount of electricity needed
must be within a certain range of millivolts in order for this to happen. If there is not enough electricity (or no electricity) being generated,
then the electromagnet no longer functions and the pilot valve shuts. When you turn the knob to the pilot position and push it in, you are in fact manually opening the valve to the
pilot flame. Once the pilot gets the thermocouple hot enough, the electromagnet engages and keeps the valve open.
This is why you need to keep the knob depressed for about 30 seconds.
After the pilot is lit and stays lit on its own after releasing the pilot know, you can then turn the knob to the "ON" position.
With manually operated safety pilots, turning the knob to the on position
will light the logs and you can adjust the flame height using the control knob.
With remote controlled systems, turning the knob to the on position simply puts the main valve in a position to be opened and closed
buy whatever means the remote control uses. In the case of a remote controlled valve, some will have a battery operated device that opens and closes the valve to the main burner, thus turning the logs
on and off. More sophisticated systems (called variable flame remotes) will have a battery operated motor attached to the flame adjustment knob that will allow you to adjust the flame height as well.
The main burner valve is designed such that if the pilot valve is closed, no gas can flow through the main valve, even if you have it in the on position.
So as long as the pilot light is on and heating the thermocouple
properly, the system is operational and gas can then be allowed to pass through the main burner valve. If the pilot light gets turned off or blown out (or in some cases gets too hot),
then all valves are closed and no gas can pass through the system.
When the main burner is turned on, either by a remote controlled unit or by manually turning a knob, gas flows through the main valve and comes out the holes in the burner.
The flame from the safety pilot is positioned just above the first several holes in the main burner, so when gas flows out of the main burner and reaches the safety pilot, it automatically ignites.
So again, if the safety pilot is not lit (or for some reason the safety pilot gets blown out), the system automatically closes both valves so that no gas will
flow through either valve until the safety pilot is re-lit.
This prevents the system from allowing gas to flow freely into your home at any time in the event that the safety pilot blows out, or someone turns on the gas to your fireplace
without lighting it.
Answers to Recent Gas Logs Questions Posted To This Page
- Question #9475 - Posted: 4/8/2014 1:29:42 AM
Gas Logs Question
QUESTION: On a RH Peterson burner, what is the difference, or pros and cons from a G45A Burner and a G45 Triple T Burner?
Is it just the certification or is there a performance difference as well?
ANSWER: The G45A has a manual safety pilot that is factory installed and tested to meet ANSI approval. The G45 is a match-light burner with no safety pilot. If you purchase a G45 and add a safety pilot it will not be installed and tested at the factory. Otherwise, both burners are identical and both are Triple T. Many cities and states require ANSI approval, so if in doubt, it is best to purchase an ANSI approved burner.
- Question #9474 - Posted: 4/7/2014 1:30:01 AM
Gas Logs Question
QUESTION: I have a zero clearance fire place that had the chimney removed when the house was re-roofed. I never intend to burn wood in it again. It never worked very well burning wood. Ventless is an option, but what are my options for a vented log? I would not want to take the vent through the roof. Can it be vented to a side wall? What are the limitations for running vent horizontally (how long)? I live in St. Louis, MO. Firebox can handle a G10 18
ANSWER: There are no options to vent a previous wood burning fireplace out a side wall, it must be vented through the roof as it was before in order to burn any gas logs, vented or ventless. Please do not burn anything in your fireplace without having he chimney installed as it was before...it will not be safe.
- Question #9467 - Posted: 4/3/2014 7:53:00 AM
Gas Logs Question
QUESTION: I am looking at model HRG45-24-P-SS. the gas line comes into the fireplace from the left side (looking forward at the fireplace). Will this burner-log set work? When I looked at the instruction manual, the diagram shows the gas line on the right.
ANSWER: You can easily reroute the gas line to the left side using a longer flex tube or black pipe. Often times, depending on the location of your gas line, the flex tube that comes with the burner will reach the other side. If it does not, then you can purchase a longer flex tube from us or from a hardware store or home center.
- Question #9455 - Posted: 2/17/2014 9:10:47 AM
Gas Logs Question
QUESTION: Cn I just order the burner since I already have a 24 " split oak log set? My existing burner is leaking. Am looking at the G46-24 SPK.
ANSWER: Yes, if you already have Peterson logs, we can supply you with the correct burner that is matched to them. The G46-24-SPK is one of the burners that is compatible with your logs. Give us a call and we will process your order over the phone. Call: 1-800-201-1193.
- Question #9454 - Posted: 2/17/2014 9:09:00 AM
Gas Logs Question
QUESTION: Hello, Thank you for taking my question. We have install installed a ventless fire place Patterson.. The unit was complete but had no logs supplied. Bought new logs. Can any ventless log be used with the burner. Or are the logs and burner sold only in sets?
ANSWER: Warning: Do not use any logs other than those designed for the particular burner you own. The logs are in fact specific to the burner. It is critical that you get the right logs because if the flame hits the logs differently than the original design it can cause the gas to burn incompletely. Incomplete combustion of gas results in the additional byproducts of soot and carbon monoxide (lethal and odorless), which will be introduced directly into your home.
- Question #9449 - Posted: 2/1/2014 3:26:13 PM
Gas Logs Question
QUESTION: I have a Peterson 18" gas log set I'm installing myself. The installation manual shows a right hand gas supply. My fireplace has a left gas supply. Can I just disassemble the burner pan and convert it to a left gas input and put the cap on the right? Or do I need to run a lot more pipe all the way from the left side to the right side? Thanks
ANSWER: If you have a matchlight system (one without a safety pilot) then you can switch the plug and orifice from one side to the other to convert it to left gas input. If you have a safety pilot, it depends on the pilot system you have: some of them can and other cannot be reversed...it will be obvious because the pilot mechanism would be upside down when reversed. If such is the case, then either get a longer flex tube from a home center, or reroute the gas line using black pipe and elbows.
- Question #9448 - Posted: 1/30/2014 9:12:57 AM
Gas Logs Question
QUESTION: We have a "Fire-Gear" vent-less propane fireplace. It gives off a noxious odor. We had it service but to no avail. We are thinking of replacing it w Peterson brand. Will this take care of our problem?
Fire Gear is not a top quality brand like Peterson, so it is quite likely that replacing them with a better quality vent free gas log from Peterson will help reduce the odor. But it is important to be aware that ALL ventless appliances produce some odor because all of the byproducts of burning the fire are introduced into the room. Propane can be particularly worse than natural gas because the quality of the propane varies from supplier to supplier. The more impurities there are in the propane, the more potential there is for smell coming from burning a ventless gas log. Although we would love to sell you a new gas log set, we cannot guarantee that it would eliminate or reduce the odor. The only way to find out would be to install them. At least in that manner, you would know for sure whether it is the log set causing the problem, or the gas you are being supplied. Read more about what causes vent-free gas logs to produce a smell
- Question #9447 - Posted: 1/30/2014 8:46:17 AM
Gas Logs Question
QUESTION: My daughter has vented gas logs in her bedroom which is about 24x36. It is her primary heat system. Recently we noticed that the ceiling and top part of her walls were becoming covered in black soot. Why would the logs start this and is it dangerous to them. They have a 1 month old that sleeps in that room as well. I have noticed that some of the baby toys that are plastic have the black on them also. I am very nervous about this. Would it be better for them to get ventless with a heatalator?
Please stop using the gas logs immediately, it is dangerous to use them if they are producing soot. Where there is soot, there is also carbon monoxide, which as you know is a lethal odorless gas. You need to have your gas logs serviced or replaced because they are no longer burning cleanly as vent free gas logs should. Some Heating and AC companies are qualified to service ventless appliances, so use your local yellow pages to call around. Or, you can use the resource on this page to locate a professional who is qualified to service your gas logs: Locate a Gas Log Service Professional
- Question #9446 - Posted: 1/26/2014 3:14:39 PM
Gas Logs Question
QUESTION: I have a Peterson real fire vented gas log system 18inch in my fireplace for several years and am very satisfied. I would like to change just the burner to make a vent free system for more heat. Is this possible. Thanks
ANSWER: Unfortunately you cannot change just the burner in order to create a ventless gas log set. The burner and logs must be designed to work together, so you will need to buy a complete setup. The reason is that ventless gas logs must burn in a very controlled manner in order to burn cleanly. Any disruption to the way the flame burns, such as touching the logs in the wrong place, will cause the gas to burn incompletely and produce exhaust...including carbon monoxide and soot. So the flames cannot touch the logs in any manner in which the system was not designed...which means you must have the correct logs and they must be stacked exactly as described in the owners manual.