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-   -   Lennox Conservator II Won't Stay Lit (http://www.diychatroom.com/f17/lennox-conservator-ii-wont-stay-lit-92896/)

bkrinke 01-20-2011 07:39 AM

Lennox Conservator II Won't Stay Lit
 
I have a Lennox Conservator II. Last year it started having problems with the ignition. This was exacerbated by the fact that the flame will only burn for a couple minutes and then shut off. Even when you are nowhere near the desired temperature. Then it has to try to re-light itself. You could hear it trying to light but the arc of electricity would not jump across. I replaced the ignition assembly and it seemed to help for a short period of time.

Now it really struggles to light itself.

What I don't understand is why after it lights itself does it shut the flame off after only a few minutes of running and then try to re-light itself. It seems to me that until the thermostat reads the desired temperature that the flame should stay on.

Please Help!!

Brad

diyorpay 01-20-2011 07:46 AM

Besides checking flame sensor 'connection', try cleaning sensor by one of the burners with emery cloth, fine steel wool or sandpaper.

For expert techs post model # of unit, not just brochure model.

bkrinke 01-20-2011 07:59 AM

I don't intend on sounding ignorant but since I simply don't know I guess that cannot be avoided.

I assume any kind of sensor would have to have a wire back to the control box. The only wire that runs anywhere near the flames is the ignition wire.

I don't see any sensors that could be a flame sensor. There are a number of wires that run down into a lower box where the fan is located but they cannot possibly check for flames down there.

I opened the fan box and all of the wires running from the upper area down to the fan area are going into another module. Nothing goes back up.

I did find a small black box that has temperatures listed on it. They start at 80 and go up. The temp is set at 100. Could this be the issue?

Brad

terrylueders 01-20-2011 09:04 AM

Its hiding!
 
The flame sensor wire is hiding somewhere. The ignitor is usually on one side and the senor on the other side. If you look into the flame camber you should see a long metal rod that is about 1/8 inch thick. This rod will be in the flame to sense it. And, should have a wire to it. Easy to clean or replace. Keep looking.

bkrinke 01-20-2011 09:16 AM

Found it. It's on the same assembly as the ignition. They are both discolored. I will remove and sand them both!!

terrylueders 01-20-2011 09:31 AM

Important message!
 
Do not touch the ignitor or sand it or even look at it too hard. It is very touchy. That is if you have a Hot Surface Ignitor. Good Luck.

bkrinke 01-20-2011 10:11 AM

Ok. Sanded the parts. For now it is lighting itself. I still wonder, is the flame supposed to stop before the temperature reaches the desired level? This causes it to re-light numerous times during the heating process. Perhaps it is designed to do this to prevent the unit from over heating?

terrylueders 01-20-2011 11:36 AM

Yes! It is working properly. Good luck.

Marty S. 01-20-2011 05:57 PM

Quote:

Originally Posted by bkrinke (Post 574349)
Ok. Sanded the parts. For now it is lighting itself. I still wonder, is the flame supposed to stop before the temperature reaches the desired level? This causes it to re-light numerous times during the heating process. Perhaps it is designed to do this to prevent the unit from over heating?

It does that BECAUSE the unit is over heating. Just a WAG but are you dealing with an old G12? If so you need to have that thing inspected by good tech.

bkrinke 01-20-2011 06:04 PM

Quote:

Originally Posted by Marty S.
It does that BECAUSE the unit is over heating. Just a WAG but are you dealing with an old G12? If so you need to have that thing inspected by good tech.

How do I know if it is a G12? And can I stop it from over heating?

yuri 01-20-2011 06:17 PM

Should have a sticker inside beside the burners usually on the left side that has a model # like G12 or G16. Get us the complete model #. Need to do a temp rise test while it is running and compare it to the specs on that sticker. AC coil may be dirty and reducing airflow etc.

bkrinke 01-21-2011 12:09 AM

Quote:

Originally Posted by yuri
Should have a sticker inside beside the burners usually on the left side that has a model # like G12 or G16. Get us the complete model #. Need to do a temp rise test while it is running and compare it to the specs on that sticker. AC coil may be dirty and reducing airflow etc.

Ok. There is a short at the base of the ignition. I have adjusted the cord into an optimal location where it sparks continuously!! Yeah!!

But wait there's more. When I run the ignition w/o natural gas it works perfectly. As soon as even a small amount of natural gas is introduced the sparks stop. When I stop and gas and blow the residual away the sparks start right back up. Go figure.

Any ideas??!!??

G12E by the way. The part number is partially damaged and I cannot read it.


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