Lennox G40 Watchguard LED Signal

Old 01-02-08, 07:35 AM
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Lennox G40 Watchguard LED Signal

My Lennox G40 model furnace switches to Watchguard sporadically. It is only 7 years old. It prevents the heater unit from lighting. I reset the system and it will fire up the furnace just fine.

What triggers the Watchgaurd?
What is it trying to tell me?
What should I be checking?

The system will heat the house fine whenever it want to, however, it will go to watchguard overnight. During the daytime it seems to do this less often.
Old 01-10-09, 11:50 AM
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same issue here

I have a G60DFV(X) Lennox that is doing the exact same thing. Mine is only 4 years old.

I am reading and learning about these things every minute. I have checked some basics like the primary limit switch and the flame rollout sensors, but I think my next step is to remove the flame sensor and clean it with steel wool.

I will let you know what I come up with.

there seems to be a number of things that can cause the Watchguard mode to engage...

I have a similar thread going, check here to see if anybody has more info
Old 01-10-09, 12:36 PM
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Cleaning the flame would be a good place to start. The furnace will reveal the fault code if you can catch it before it goes into safegard lockout.
Old 01-10-09, 12:46 PM
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As I understand it, the Watchguard lockout can be caused by a wide variety of problems:

A: Burners failed to ignite
B: Limit open more than 3 minutes
C: Lost flame sense 5 times in one heating cycle
D: Pressure switch opened 5 times in one heating cycle

Jg, it's rapidly becomes confusing to try to discuss different problems on the same thread. I'd like to suggest you start a new thread.

You have a good description of what is happening with your furnace on the link.

And doit---

As Skip suggested, you need to identify what is quitting before the Watchguard lockout. Before it locks out it typically identifies problems and you can probably observe how far along in the start up sequence the furnace gets before it quits.
Old 01-10-09, 07:19 PM
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thanks Skip, I will try to catch the code prior to the furnace going into Watchguard mode.

Seattle, thanks for the response. I do have my own thread going on my particular issue, I just wanted the originator of this thread to know where he/she can get more info b/c the issue sounds similar. http://forum.doityourself.com/gas-oi...ml#post1499390

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